This patch makes FoldBranchToCommonDest merge branch conditions into `select i1` rather than `and/or i1` when it is called by SimplifyCFG.
It is known that merging conditions into and/or is poison-unsafe, and this is towards making things *more* correct by removing possible miscompilations.
Currently, InstCombine simply consumes these selects into and/or of i1 (which is also unsafe), so the visible effect would be very small. The unsafe select -> and/or transformation will be removed in the future.
There has been efforts for updating optimizations to support the select form as well, and they are linked to D93065.
The safe transformation is fired when it is called by SimplifyCFG only. This is done by setting the new `PoisonSafe` argument as true.
Another place that calls FoldBranchToCommonDest is LoopSimplify. `PoisonSafe` flag is set to false in this case because enabling it has a nontrivial impact in performance because SCEV is more conservative with select form and InductiveRangeCheckElimination isn't aware of select form of and/or i1.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D95026
Hello all,
I'm trying to fix unsafe propagation of poison values in and/or conditions by using
equivalent select forms (`select i1 A, i1 B, i1 false` and `select i1 A, i1 true, i1 false`)
instead.
D93065 has links to patches for this.
This patch allows unswitch to happen if the condition is in this form as well.
`collectHomogenousInstGraphLoopInvariants` is updated to keep traversal if
Root and the visiting I matches both m_LogicalOr()/m_LogicalAnd().
Other than this, the remaining changes are almost straightforward and simply replaces
Instruction::And/Or check with match(m_LogicalOr()/m_LogicalAnd()).
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D97756
When materializing an available load value, do not explicitly
materialize the undef values from dead blocks. Doing so will
will force creation of a phi with an undef operand, even if there
is a dominating definition. The phi will be folded away on
subsequent GVN iterations, but by then we may have already
poisoned MDA cache slots.
Simply don't register these values in the first place, and let
SSAUpdater do its thing.
Add support to widen call instructions in VPlan native path by using a correct recipe when such instructions are encountered. This is already used by inner loop vectorizer.
Previously call instructions got handled by wrong recipes and resulted in unreachable instruction errors like this one: https://bugs.llvm.org/show_bug.cgi?id=48139.
Patch by Mauri Mustonen <mauri.mustonen@tuni.fi>
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D97278
It's just a wrong thing to do.
We introduce inttoptr where there were none, which results in
loosing all provenance information because we no longer have a GEP{i,},
and pessimize all future optimizations,
because we are basically not allowed to look past `inttoptr`.
(gep i8* X, -(ptrtoint Y)) *is* the canonical form.
So just drop this fold.
Noticed while reviewing D98120.
These intrinsics, not the icmp+select are the canonical form nowadays,
so we might as well directly emit them.
This should not cause any regressions, but if it does,
then then they would needed to be fixed regardless.
Note that this doesn't deal with `SCEVExpander::isHighCostExpansion()`,
but that is a pessimization, not a correctness issue.
Additionally, the non-intrinsic form has issues with undef,
see https://reviews.llvm.org/D88287#2587863
We have the `enable-loopinterchange` option in legacy pass manager but not in NPM.
Add `LoopInterchange` pass to the optimization pipeline (at the same position as before)
when `enable-loopinterchange` is turned on.
Reviewed By: aeubanks, fhahn
Differential Revision: https://reviews.llvm.org/D98116
GVN basically doesn't handle phi nodes at all. This is for a reason - we can't value number their inputs since the predecessor blocks have probably not been visited yet.
However, it also creates a significant pass ordering problem. As it stands, instcombine and simplifycfg ends up implementing CSE of phi nodes. This means that for any series of CSE opportunities intermixed with phi nodes, we end up having to alternate instcombine/simplifycfg and gvn to make progress.
This patch handles the simplest case by simply preprocessing the phi instructions in a block, and CSEing them if they are syntactically identical. This turns out to be powerful enough to handle many cases in a single invocation of GVN since blocks which use the cse'd phi results are visited after the block containing the phi. If there's a CSE opportunity in one the phi predecessors required to recognize the phi CSE opportunity, that will require a second iteration on the function. (Still within a single run of gvn though.)
Compile time wise, this could go either way. On one hand, we're potentially causing GVN to iterate over the function more. On the other, we're cutting down on iterations between two passes and potentially shrinking the IR aggressively. So, a bit unclear what to expect.
Note that this does still rely on instcombine to canonicalize block order of the phis, but that's a one time transformation independent of the values incoming to the phi.
Differential Revision: https://reviews.llvm.org/D98080
The last two operands to a gc.relocate represent indices into the associated gc.statepoint's gc bundle list. (Effectively, gc.relocates are projections from the gc.statepoints multiple return values.)
We can use this to recognize when two gc.relocates are equivalent (and can be CSEd), even when the indices are non-equal. This is particular useful when considering a chain of multiple statepoints as it lets us eliminate all duplicate gc.relocates in a single pass.
Differential Revision: https://reviews.llvm.org/D97974
(Note: Part of the reviewed change was split and landed as f352463a)
For some reason, we had been marking gc.relocates as reading memory. There's no known reason for this, and I suspect it to be a legacy of very early implementation conservatism. gc.relocate and gc.result are simply projections of the return values from the associated statepoint. Note that the LangRef has always declared them readnone.
The EarlyCSE change is simply moving the special casing from readonly to readnone handling.
As noted by the test diffs, this does allow some additional CSE when relocates are separated by stores, but since we generate gc.relocates in batches, this is unlikely to help anything in practice.
This was reviewed as part of https://reviews.llvm.org/D97974, but split at reviewer request before landing. The motivation is to enable the GVN changes in that patch.
If we have a value live over a call which is used for deopt at the call, we know that the value must be a base pointer. We can avoid potentially inserting IR to materialize a base for this value.
In it's current form, this is mostly a compile time optimization. Building the base pointer graph (and then optimizing it away again) is a relatively expensive operation. We also sometimes end up with better codegen in practice - due to failures in optimizing away the inserted base pointer propogation - but those are optimization bugs we're fixing concurrently.
The alternative to this would be to extend the base pointer inference with the ability to generally reuse multiple-base input instructions (phis and selects). That's somewhat invasive and complicated, so we're defering it a bit longer.
Differential Revision: https://reviews.llvm.org/D97885
This patch adds a new metadata node, DIArgList, which contains a list of SSA
values. This node is in many ways similar in function to the existing
ValueAsMetadata node, with the difference being that it tracks a list instead of
a single value. Internally, it uses ValueAsMetadata to track the individual
values, but there is also a reasonable amount of DIArgList-specific
value-tracking logic on top of that. Similar to ValueAsMetadata, it is a special
case in parsing and printing due to the fact that it requires a function state
(as it may reference function-local values).
This patch should not result in any immediate functional change; it allows for
DIArgLists to be parsed and printed, but debug variable intrinsics do not yet
recognize them as a valid argument (outside of parsing).
Differential Revision: https://reviews.llvm.org/D88175
There are certain loops like this below:
for (int i = 0; i < n; i++) {
a[i] = b[i] + 1;
*inv = a[i];
}
that can only be vectorised if we are able to extract the last lane of the
vectorised form of 'a[i]'. For fixed width vectors this already works since
we know at compile time what the final lane is, however for scalable vectors
this is a different story. This patch adds support for extracting the last
lane from a scalable vector using a runtime determined lane value. I have
added support to VPIteration for runtime-determined lanes that still permit
the caching of values. I did this by introducing a new class called VPLane,
which describes the lane we're dealing with and provides interfaces to get
both the compile-time known lane and the runtime determined value. Whilst
doing this work I couldn't find any explicit tests for extracting the last
lane values of fixed width vectors so I added tests for both scalable and
fixed width vectors.
Differential Revision: https://reviews.llvm.org/D95139
Initial support for using the OpenMPIRBuilder by clang to generate loops using the OpenMPIRBuilder. This initial support is intentionally limited to:
* Only the worksharing-loop directive.
* Recognizes only the nowait clause.
* No loop nests with more than one loop.
* Untested with templates, exceptions.
* Semantic checking left to the existing infrastructure.
This patch introduces a new AST node, OMPCanonicalLoop, which becomes parent of any loop that has to adheres to the restrictions as specified by the OpenMP standard. These restrictions allow OMPCanonicalLoop to provide the following additional information that depends on base language semantics:
* The distance function: How many loop iterations there will be before entering the loop nest.
* The loop variable function: Conversion from a logical iteration number to the loop variable.
These allow the OpenMPIRBuilder to act solely using logical iteration numbers without needing to be concerned with iterator semantics between calling the distance function and determining what the value of the loop variable ought to be. Any OpenMP logical should be done by the OpenMPIRBuilder such that it can be reused MLIR OpenMP dialect and thus by flang.
The distance and loop variable function are implemented using lambdas (or more exactly: CapturedStmt because lambda implementation is more interviewed with the parser). It is up to the OpenMPIRBuilder how they are called which depends on what is done with the loop. By default, these are emitted as outlined functions but we might think about emitting them inline as the OpenMPRuntime does.
For compatibility with the current OpenMP implementation, even though not necessary for the OpenMPIRBuilder, OMPCanonicalLoop can still be nested within OMPLoopDirectives' CapturedStmt. Although OMPCanonicalLoop's are not currently generated when the OpenMPIRBuilder is not enabled, these can just be skipped when not using the OpenMPIRBuilder in case we don't want to make the AST dependent on the EnableOMPBuilder setting.
Loop nests with more than one loop require support by the OpenMPIRBuilder (D93268). A simple implementation of non-rectangular loop nests would add another lambda function that returns whether a loop iteration of the rectangular overapproximation is also within its non-rectangular subset.
Reviewed By: jdenny
Differential Revision: https://reviews.llvm.org/D94973
sample loader pass.
In https://reviews.llvm.org/rG5fb65c02ca5e91e7e1a00e0efdb8edc899f3e4b9,
to prevent repeated indirect call promotion for the same indirect call
and the same target, we used zero-count value profile to indicate an
indirect call has been promoted for a certain target. We removed
PromotedInsns cache in the same patch. However, there was a problem in
that patch described below, and that problem led me to add PromotedInsns
back as a mitigation in
https://reviews.llvm.org/rG4ffad1fb489f691825d6c7d78e1626de142f26cf.
When we get value profile from metadata by calling getValueProfDataFromInst,
we need to specify the maximum possible number of values we expect to read.
We uses MaxNumPromotions in the last patch so the maximum number of value
information extracted from metadata is MaxNumPromotions. If we have many
values including zero-count values when we write the metadata, some of them
will be dropped when we read them because we only read MaxNumPromotions
values. It will allow repeated indirect call promotion again. We need to
make sure if there are values indicating promoted targets, those values need
to be saved in metadata with higher priority than other values.
The patch fixed that problem. We change to use -1 to represent the count
of a promoted target instead of 0 so it is easier to sort the values.
When we prepare to update the metadata in updateIDTMetaData, we will sort
the values in the descending count order and extract only MaxNumPromotions
values to write into metadata. Since -1 is the max uint64_t number, if we
have equal to or less than MaxNumPromotions of -1 count values, they will
all be kept in metadata. If we have more than MaxNumPromotions of -1 count
values, we will only save MaxNumPromotions such values maximally. In such
case, we have logic in place in doesHistoryAllowICP to guarantee no more
promotion in sample loader pass will happen for the indirect call, because
it has been promoted enough.
With this change, now we can remove PromotedInsns without problem.
Differential Revision: https://reviews.llvm.org/D97350
This is included from IR files, and IR doesn't/can't depend on Analysis
(because Analysis depends on IR).
Also fix the implementation - don't use non-member static in headers, as
it leads to ODR violations, inaccurate "unused function" warnings, etc.
And fix the header protection macro name (we don't generally include
"LIB" in the names, so far as I can tell).
This code assumed that FP math was only permissable if it was
fully "fast", so it hard-coded "fast" when creating new instructions.
The underlying code already allows matching recurrences/reductions
that are only "reassoc", so this change should prevent the potential
miscompile seen in the test diffs (we created "fast" ops even though
none existed in the original code).
I don't know if we need to create the temporary IRBuilder objects
used here, so that could be follow-up clean-up.
There's an open question about whether we should require "nsz" in
addition to "reassoc" here. InstCombine uses that combo for its
reassociative folds, but I think codegen is not as strict.
This enhances the auto-init remark with information about the variable
that is auto-initialized.
This is based of debug info if available, or alloca names (mostly for
development purposes).
```
auto-init.c:4:7: remark: Call to memset inserted by -ftrivial-auto-var-init. Memory operation size: 4096 bytes.Variables: var (4096 bytes). [-Rpass-missed=annotation-remarks]
int var[1024];
^
```
This allows to see things like partial initialization of a variable that
the optimizer won't be able to completely remove.
Differential Revision: https://reviews.llvm.org/D97734
explicitly emitting retainRV or claimRV calls in the IR
This reapplies ed4718eccb, which was reverted
because it was causing a miscompile. The bug that was causing the miscompile
has been fixed in 75805dce5f.
Original commit message:
Background:
This fixes a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.
https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
What this patch does to fix the problem:
- The front-end adds operand bundle "clang.arc.attachedcall" to calls,
which indicates the call is implicitly followed by a marker
instruction and an implicit retainRV/claimRV call that consumes the
call result. In addition, it emits a call to
@llvm.objc.clang.arc.noop.use, which consumes the call result, to
prevent the middle-end passes from changing the return type of the
called function. This is currently done only when the target is arm64
and the optimization level is higher than -O0.
- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
with the operand bundle in the IR and removes the inserted calls after
processing the function.
- ARC contract pass emits retainRV/claimRV calls after the call with the
operand bundle. It doesn't remove the operand bundle on the call since
the backend needs it to emit the marker instruction. The retainRV and
claimRV calls are emitted late in the pipeline to prevent optimization
passes from transforming the IR in a way that makes it harder for the
ARC middle-end passes to figure out the def-use relationship between
the call and the retainRV/claimRV calls (which is the cause of
PR31925).
- The function inliner removes an autoreleaseRV call in the callee if
nothing in the callee prevents it from being paired up with the
retainRV/claimRV call in the caller. It then inserts a release call if
claimRV is attached to the call since autoreleaseRV+claimRV is
equivalent to a release. If it cannot find an autoreleaseRV call, it
tries to transfer the operand bundle to a function call in the callee.
This is important since the ARC optimizer can remove the autoreleaseRV
returning the callee result, which makes it impossible to pair it up
with the retainRV/claimRV call in the caller. If that fails, it simply
emits a retain call in the IR if retainRV is attached to the call and
does nothing if claimRV is attached to it.
- SCCP refrains from replacing the return value of a call with a
constant value if the call has the operand bundle. This ensures the
call always has at least one user (the call to
@llvm.objc.clang.arc.noop.use).
- This patch also fixes a bug in replaceUsesOfNonProtoConstant where
multiple operand bundles of the same kind were being added to a call.
Future work:
- Use the operand bundle on x86-64.
- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls with the operand bundles.
rdar://71443534
Differential Revision: https://reviews.llvm.org/D92808
This patch updates the scope line to point to the suspend point. This
makes the first address in the function point to the first source line
in the resume function rather than the function declaration. Without
this the line table "jumps" from the beginning of the function to the
suspend point at the beginning.
rdar://73386346
Differential Revision: https://reviews.llvm.org/D97345
For logical or/and reductions we emit regular intrinsics @llvm.vector.reduce.or/and.vxi1 calls.
These intrinsics are not effective for the logical or/and reductions,
especially if the optimizer is able to emit short circuit versions of
the scalar or/and instructions and vector code gets less effective than
the scalar version.
Instead, or reduction for i1 can be represented as:
```
%val = bitcast <ReduxWidth x i1> to iReduxWidth
%res = cmp ne iReduxWidth %val, 0
```
and reduction for i1 can be represented as:
```
%val = bitcast <ReduxWidth x i1> to iReduxWidth
%res = cmp eq iReduxWidth %val, 11111
```
This improves perfromance of the vector code significantly and make it
to outperform short circuit scalar code.
Part of D57059.
Differential Revision: https://reviews.llvm.org/D97406
Similar to b3a33553ae, but this shows a TODO and a potential
miscompile is already present.
We are tracking an FP instruction that does *not* have FMF (reassoc)
properties, so calling that "Unsafe" seems opposite of the common
reading.
I also removed one getter method by rolling the null check into
the access. Further simplification may be possible.
The motivation is to clean up the interactions between FMF and
function-level attributes in these classes and their callers.
The new test shows that there is an existing bug somewhere in
the callers. We assumed that the original code was fully 'fast'
and so we produced IR with 'fast' even though it was just 'reassoc'.
We are tracking an FP instruction that does *not* have FMF (reassoc)
properties, so calling that "Unsafe" seems opposite of the common
reading.
I also removed one getter method by rolling the null check into
the access. Further simplification seems possible.
The motivation is to clean up the interactions between FMF and
function-level attributes in these classes and their callers.
Same dangling probes are redundant since they all have the same semantic that is to rely on the counts inference tool to get reasonable count for the same original block. Therefore, there's no need to keep multiple copies of them. I've seen jump threading created tons of redundant dangling probes that slowed down the compiler dramatically. Other optimization passes can also result in redundant probes though without an observed impact so far.
This change removes block-wise redundant dangling probes specifically introduced by jump threading. To support removing redundant dangling probes caused by all other passes, a final function-wise deduplication is also added.
An 18% size win of the .pseudo_probe section was seen for SPEC2017. No performance difference was observed.
Differential Revision: https://reviews.llvm.org/D97482
This change fixes a couple places where the pseudo probe intrinsic blocks optimizations because they are not naturally removable. To unblock those optimizations, the blocking pseudo probes are moved out of the original blocks and tagged dangling, instead of allowing pseudo probes to be literally removed. The reason is that when the original block is removed, we won't be able to sample it. Instead of assigning it a zero weight, moving all its pseudo probes into another block and marking them dangling should allow the counts inference a chance to assign them a more reasonable weight. We have not seen counts quality degradation from our experiments.
The optimizations being unblocked are:
1. Removing conditional probes for if-converted branches. Conditional probes are tagged dangling when their homing branch arms are folded so that they will not be over-counted.
2. Unblocking jump threading from removing empty blocks. Pseudo probe prevents jump threading from removing logically empty blocks that only has one unconditional jump instructions.
3. Unblocking SimplifyCFG and MIR tail duplicate to thread empty blocks and blocks with redundant branch checks.
Since dangling probes are logically deleted, they should not consume any samples in LTO postLink. This can be achieved by setting their distribution factors to zero when dangled.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D97481
We don't need a bool and an enum to express the three options we
currently have. This makes the interface nicer and much easier to
use optional dependencies. Also avoids mistakes where the bool is
false and enum ignored.
This is an attempt to improve handling of partial overlaps in case of unaligned begin\end.
Existing implementation just bails out if it encounters such cases. Even when it doesn't I believe existing code checking alignment constraints is not quite correct. It tries to ensure alignment of the "later" start/end offset while should be preserving relative alignment between earlier and later start/end.
The idea behind the change is simple. When start/end is not aligned as we wish instead of bailing out let's adjust it as necessary to get desired alignment.
I'll update with performance results as measured by the test-suite...it's still running...
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D93530
statepoint intrinsic can be used in invoke context,
so it should be handled in visitCallBase to cover both call and invoke.
Reviewers: reames, dantrushin
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D97833
See pr46990(https://bugs.llvm.org/show_bug.cgi?id=46990). LICM should not sink store instructions to loop exit blocks which cross coro.suspend intrinsics. This breaks semantic of coro.suspend intrinsic which return to caller directly. Also this leads to use-after-free if the coroutine is freed before control returns to the caller in multithread environment.
This patch disable promotion by check whether loop contains coro.suspend intrinsics.
This is a resubmit of D86190.
Disabling LICM for loops with coroutine suspension is a better option not only for correctness purpose but also for performance purpose.
In most cases LICM sinks memory operations. In the case of coroutine, sinking memory operation out of the loop does not improve performance since coroutien needs to get data from the frame anyway. In fact LICM would hurt coroutine performance since it adds more entries to the frame.
Differential Revision: https://reviews.llvm.org/D96928
Probably should have done this before landing, but I forgot.
Basic idea is to avoid using the SCEV predicate when it doesn't buy us anything. Also happens to set us up for handling non-add recurrences in the future if desired.
LSR goes to some lengths to schedule IV increments such that %iv and %iv.next never need to overlap. This is fairly fundamental to LSRs cost model. LSR assumes that an addrec can be represented with a single register. If %iv and %iv.next have to overlap, then that assumption does not hold.
The bug - which this patch is fixing - is that LSR only does this scheduling for IVs which it inserts, but it's cost model assumes the same for existing IVs that it reuses. It will rewrite existing IV users such that the no-overlap property holds, but will not actually reschedule said IV increment.
As you can see from the relatively lack of test updates, this doesn't actually impact codegen much. The main reason for doing it is to make a follow up patch series which improves post-increment use and scheduling easier to follow.
Differential Revision: https://reviews.llvm.org/D97219
`__llvm_prf_vnodes` and `__llvm_prf_names` are used by runtime but not
referenced via relocation in the translation unit.
With `-z start-stop-gc` (LLD 13 (D96914); GNU ld 2.37 https://sourceware.org/bugzilla/show_bug.cgi?id=27451),
the linker does not let `__start_/__stop_` references retain their sections.
Place `__llvm_prf_vnodes` and `__llvm_prf_names` in `llvm.used` to make
them retained by the linker.
This patch changes most existing `UsedVars` cases to `CompilerUsedVars`
to reflect the ideal state - if the binary format properly supports
section based GC (dead stripping), `llvm.compiler.used` should be sufficient.
`__llvm_prf_vnodes` and `__llvm_prf_names` are switched to `UsedVars`
since we want them to be unconditionally retained by both compiler and linker.
Behaviors on COFF/Mach-O are not affected.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D97649
Before we used the same argument as the entry point. The resume partial
function might want to use a different ABI for its context argument
Differential Revision: https://reviews.llvm.org/D97333
This caused miscompiles of Chromium tests for iOS due clobbering of live
registers. See discussion on the code review for details.
> Background:
>
> This fixes a longstanding problem where llvm breaks ARC's autorelease
> optimization (see the link below) by separating calls from the marker
> instructions or retainRV/claimRV calls. The backend changes are in
> https://reviews.llvm.org/D92569.
>
> https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
>
> What this patch does to fix the problem:
>
> - The front-end adds operand bundle "clang.arc.attachedcall" to calls,
> which indicates the call is implicitly followed by a marker
> instruction and an implicit retainRV/claimRV call that consumes the
> call result. In addition, it emits a call to
> @llvm.objc.clang.arc.noop.use, which consumes the call result, to
> prevent the middle-end passes from changing the return type of the
> called function. This is currently done only when the target is arm64
> and the optimization level is higher than -O0.
>
> - ARC optimizer temporarily emits retainRV/claimRV calls after the calls
> with the operand bundle in the IR and removes the inserted calls after
> processing the function.
>
> - ARC contract pass emits retainRV/claimRV calls after the call with the
> operand bundle. It doesn't remove the operand bundle on the call since
> the backend needs it to emit the marker instruction. The retainRV and
> claimRV calls are emitted late in the pipeline to prevent optimization
> passes from transforming the IR in a way that makes it harder for the
> ARC middle-end passes to figure out the def-use relationship between
> the call and the retainRV/claimRV calls (which is the cause of
> PR31925).
>
> - The function inliner removes an autoreleaseRV call in the callee if
> nothing in the callee prevents it from being paired up with the
> retainRV/claimRV call in the caller. It then inserts a release call if
> claimRV is attached to the call since autoreleaseRV+claimRV is
> equivalent to a release. If it cannot find an autoreleaseRV call, it
> tries to transfer the operand bundle to a function call in the callee.
> This is important since the ARC optimizer can remove the autoreleaseRV
> returning the callee result, which makes it impossible to pair it up
> with the retainRV/claimRV call in the caller. If that fails, it simply
> emits a retain call in the IR if retainRV is attached to the call and
> does nothing if claimRV is attached to it.
>
> - SCCP refrains from replacing the return value of a call with a
> constant value if the call has the operand bundle. This ensures the
> call always has at least one user (the call to
> @llvm.objc.clang.arc.noop.use).
>
> - This patch also fixes a bug in replaceUsesOfNonProtoConstant where
> multiple operand bundles of the same kind were being added to a call.
>
> Future work:
>
> - Use the operand bundle on x86-64.
>
> - Fix the auto upgrader to convert call+retainRV/claimRV pairs into
> calls with the operand bundles.
>
> rdar://71443534
>
> Differential Revision: https://reviews.llvm.org/D92808
This reverts commit ed4718eccb.
This is a part of https://reviews.llvm.org/D95835.
One issue is about origin load optimization: see the
comments of useCallbackLoadLabelAndOrigin
@gbalats This change may have some conflicts with your 8bit change. PTAL the change at visitLoad.
Reviewed By: morehouse, gbalats
Differential Revision: https://reviews.llvm.org/D97570
This addresses ~50 clang-tidy warnings on dfsan instrumentation pass.
It also contains some refactoring (all non-functional changes) to eliminate some variables and simplify code.
Reviewed By: stephan.yichao.zhao
Differential Revision: https://reviews.llvm.org/D97714
Even when MemorySSA-based LICM is used, an AST is still populated
for scalar promotion. As the AST has quadratic complexity, a lot
of time is spent in this step despite the existing access count
limit. This patch optimizes the identification of promotable stores.
The idea here is pretty simple: We're only interested in must-alias
mod sets of loop invariant pointers. As such, only populate the AST
with loop-invariant loads and stores (anything else is definitely
not promotable) and then discard any sets which alias with any of
the remaining, definitely non-promotable accesses.
If we promoted something, check whether this has made some other
accesses loop invariant and thus possible promotion candidates.
This is much faster in practice, because we need to perform AA
queries for O(NumPromotable^2 + NumPromotable*NumNonPromotable)
instead of O(NumTotal^2), and NumPromotable tends to be small.
Additionally, promotable accesses have loop invariant pointers,
for which AA is cheaper.
This has a signicant positive compile-time impact. We save ~1.8%
geomean on CTMark at O3, with 6% on lencod in particular and 25%
on individual files.
Conceptually, this change is NFC, but may not be so in practice,
because the AST is only an approximation, and can produce
different results depending on the order in which accesses are
added. However, there is at least no impact on the number of promotions
(licm.NumPromoted) in test-suite O3 configuration with this change.
Differential Revision: https://reviews.llvm.org/D89264
It is possible to merge reuse and reorder shuffles and reduce the total
cost of the vectorization tree/number of final instructions.
Differential Revision: https://reviews.llvm.org/D94992
`__llvm_prf_vnodes` and `__llvm_prf_names` are used by runtime but not
referenced via relocation in the translation unit.
With `-z start-stop-gc` (D96914 https://sourceware.org/bugzilla/show_bug.cgi?id=27451),
the linker no longer lets `__start_/__stop_` references retain them.
Place `__llvm_prf_vnodes` and `__llvm_prf_names` in `llvm.used` to make
them retained by the linker.
This patch changes most existing `UsedVars` cases to `CompilerUsedVars`
to reflect the ideal state - if the binary format properly supports
section based GC (dead stripping), `llvm.compiler.used` should be sufficient.
`__llvm_prf_vnodes` and `__llvm_prf_names` are switched to `UsedVars`
since we want them to be unconditionally retained by both compiler and linker.
Behaviors on other COFF/Mach-O are not affected.
Differential Revision: https://reviews.llvm.org/D97649
This seems to be more of a Clang thing rather than a generic LLVM thing,
so this moves it out of LLVM pipelines and as Clang extension hooks into
LLVM pipelines.
Move the post-inline EEInstrumentation out of the backend pipeline and
into a late pass, similar to other sanitizer passes. It doesn't fit
into the codegen pipeline.
Also fix up EntryExitInstrumentation not running at -O0 under the new
PM. PR49143
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D97608
Update the deletion order when destroying VPBasicBlocks. This ensures
recipes that depend on earlier ones in the block are removed first.
Otherwise this may cause issues when recipes have remaining users later
in the block.
This patch updates LV to generate the runtime checks just after cost
modeling, to allow a more precise estimate of the actual cost of the
checks. This information will be used in future patches to generate
larger runtime checks in cases where the checks only make up a small
fraction of the expected scalar loop execution time.
The runtime checks are created up-front in a temporary block to allow better
estimating the cost and un-linked from the existing IR. After deciding to
vectorize, the checks are moved backed. If deciding not to vectorize, the
temporary block is completely removed.
This patch is similar in spirit to D71053, but explores a different
direction: instead of delaying the decision on whether to vectorize in
the presence of runtime checks it instead optimistically creates the
runtime checks early and discards them later if decided to not
vectorize. This has the advantage that the cost-modeling decisions
can be kept together and can be done up-front and thus preserving the
general code structure. I think delaying (part) of the decision to
vectorize would also make the VPlan migration a bit harder.
One potential drawback of this patch is that we speculatively
generate IR which we might have to clean up later. However it seems like
the code required to do so is quite manageable.
Reviewed By: lebedev.ri, ebrevnov
Differential Revision: https://reviews.llvm.org/D75980
In the example based on:
https://llvm.org/PR49218
...we are crashing because poison is a subclass of undef, so we merge blocks and create:
PHI node has multiple entries for the same basic block with different incoming values!
%k3 = phi i64 [ poison, %entry ], [ %k3, %g ], [ undef, %entry ]
If both poison and undef values are incoming, we soften the poison values to undef.
Differential Revision: https://reviews.llvm.org/D97495
Many optimizers (e.g. GlobalOpt/ConstantMerge) do not respect linker semantics
for comdat and may not discard the sections as a unit.
The interconnected `__llvm_prf_{cnts,data}` sections (in comdat for ELF)
are similar to D97432: `__profd_` is not directly referenced, so
`__profd_` may be discarded while `__profc_` is retained, breaking the
interconnection. We currently conservatively add all such sections to
`llvm.used` and let the linker do GC for ELF.
In D97448, we will change GlobalObject's in the llvm.used list to use SHF_GNU_RETAIN,
causing the metadata sections to be unnecessarily retained (some `check-profile` tests check for GC).
Use `llvm.compiler.used` to retain the current GC behavior.
Differential Revision: https://reviews.llvm.org/D97585
This will allow identifying exactly how many shadow bytes were used
during compilation, for when fast8 mode is introduced.
Also, it will provide a consistent matching point for instrumentation
tests so that the exact llvm type used (i8 or i16) for the shadow can
be replaced by a pattern substitution. This is handy for tests with
multiple prefixes.
Reviewed by: stephan.yichao.zhao, morehouse
Differential Revision: https://reviews.llvm.org/D97409
This is a part of https://reviews.llvm.org/D95835.
Each customized function has two wrappers. The
first one dfsw is for the normal shadow propagation. The second one dfso is used
when origin tracking is on. It calls the first one, and does additional
origin propagation. Which one to use can be decided at instrumentation
time. This is to ensure minimal additional overhead when origin tracking
is off.
Reviewed-by: morehouse
Differential Revision: https://reviews.llvm.org/D97483
`__sancov_pcs` parallels the other metadata section(s). While some optimizers
(e.g. GlobalDCE) respect linker semantics for comdat and retain or discard the
sections as a unit, some (e.g. GlobalOpt/ConstantMerge) do not. So we have to
conservatively retain all unconditionally in the compiler.
When a comdat is used, the COFF/ELF linkers' GC semantics ensure the
associated parallel array elements are retained or discarded together,
so `llvm.compiler.used` is sufficient.
Otherwise (MachO (see rL311955/rL311959), COFF special case where comdat is not
used), we have to use `llvm.used` to conservatively make all sections retain by
the linker. This will fix the Windows problem once internal linkage
GlobalObject's in `llvm.used` are retained via `/INCLUDE:`.
Reviewed By: morehouse, vitalybuka
Differential Revision: https://reviews.llvm.org/D97432
collectBitParts uses int8_t for the bit indices, leaving a 128-bit limit.
We already test for this before calling collectBitParts, but rGb94c215592bd added truncate handling which meant we could end up processing wider integers.
Thanks to @manojgupta for the repro.
This patch modifies TryToSinkInstruction in the InstCombine pass, to prevent
redundant debug intrinsics from being produced, and also prevent the intrinsics
from being emitted in an incorrect order. It does this by ensuring that when
this pass sinks an instruction and creates clones of the debug intrinsics that
use that instruction, it inserts those debug intrinsics in their original order,
and only inserts the last debug intrinsic for each variable in the Instruction's
block.
Differential revision: https://reviews.llvm.org/D95463
DFSan at store does store shadow data; store app data; and at load does
load shadow data; load app data.
When an application data is atomic, one overtainting case is
thread A: load shadow
thread B: store shadow
thread B: store app
thread A: load app
If the application address had been used by other flows, thread A reads
previous shadow, causing overtainting.
The change is similar to MSan's solution.
1) enforce ordering of app load/store
2) load shadow after load app; store shadow before shadow app
3) do not track atomic store by reseting its shadow to be 0.
The last one is to address a case like this.
Thread A: load app
Thread B: store shadow
Thread A: load shadow
Thread B: store app
This approach eliminates overtainting as a trade-off between undertainting
flows via shadow data race.
Note that this change addresses only native atomic instructions, but
does not support builtin libcalls yet.
https://llvm.org/docs/Atomics.html#libcalls-atomic
Reviewed-by: morehouse
Differential Revision: https://reviews.llvm.org/D97310
And then push those change throughout LLVM.
Keep the old signature in Clang's CGBuilder for now -- that will be
updated in a follow-on patch (D97224).
The MLIR LLVM-IR dialect is not updated to support the new alignment
attribute, but preserves its existing behavior.
Differential Revision: https://reviews.llvm.org/D97223
This now analyzes calls to both intrinsics and functions.
For intrinsics, grab the ones we know and care about (mem* family) and
analyze the arguments.
For calls, use TLI to get more information about the libcalls, then
analyze the arguments if known.
```
auto-init.c:4:7: remark: Call to memset inserted by -ftrivial-auto-var-init. Memory operation size: 4096 bytes. [-Rpass-missed=annotation-remarks]
int var[1024];
^
```
Differential Revision: https://reviews.llvm.org/D97489
This adds support for analyzing the instruction with the !annotation
"auto-init" in order to generate a more user-friendly remark.
For now, support the store size, and whether it's atomic/volatile.
Example:
```
auto-init.c:4:7: remark: Store inserted by -ftrivial-auto-var-init.Store size: 4 bytes. [-Rpass-missed=annotation-remarks]
int var;
^
```
Differential Revision: https://reviews.llvm.org/D97412
Using the !annotation metadata, emit remarks pointing to code added by
`-ftrivial-auto-var-init` that survived the optimizer.
Example:
```
auto-init.c:4:7: remark: Initialization inserted by -ftrivial-auto-var-init. [-Rpass-missed=annotation-remarks]
int buf[1024];
^
```
The tests are testing various situations like calls/stores/other
instructions, with debug locations, and extra debug information on
purpose: more patches will come to improve the reporting to make it more
user-friendly, and these tests will show how the reporting evolves.
Differential Revision: https://reviews.llvm.org/D97405
This doesn't actually reproduce with a dbg.declare(i8* null, ...)
which produces a non-null null Value, but I have seen this show up in
crash logs. I'm suspecting that there may be another pass forcibly
setting the operand to a nullptr.
In SanitizerCoverage, the metadata sections (`__sancov_guards`,
`__sancov_cntrs`, `__sancov_bools`) are referenced by functions. After
inlining, such a `__sancov_*` section can be referenced by more than one
functions, but its sh_link still refers to the original function's section.
(Note: a SHF_LINK_ORDER section referenced by a section other than its linked-to
section violates the invariant.)
If the original function's section is discarded (e.g. LTO internalization +
`ld.lld --gc-sections`), ld.lld may report a `sh_link points to discarded section` error.
This above reasoning means that `!associated` is not appropriate to be called by
an inlinable function. Non-interposable functions are inline candidates, so we
have to drop `!associated`. A `__sancov_pcs` is not referenced by other sections
but is expected to parallel a metadata section, so we have to make sure the two
sections are retained or discarded at the same time. A section group does the
trick. (Note: we have a module ctor, so `getUniqueModuleId` guarantees to
return a non-empty string, and `GetOrCreateFunctionComdat` guarantees to return
non-null.)
For interposable functions, we could keep using `!associated`, but
LTO can change the linkage to `internal` and allow such functions to be inlinable,
so we have to drop `!associated`, too. To not interfere with section
group resolution, we need to use the `noduplicates` variant (section group flag 0).
(This allows us to get rid of the ModuleID parameter.)
In -fno-pie and -fpie code (mostly dso_local), instrumented interposable
functions have WeakAny/LinkOnceAny linkages, which are rare. So the
section group header overload should be low.
This patch does not change the object file output for COFF (where `!associated` is ignored).
Reviewed By: morehouse, rnk, vitalybuka
Differential Revision: https://reviews.llvm.org/D97430
This patch makes SampleProfileLoaderBaseImpl a template class so it
can be used in CodeGen transformation.
Noticeable changes:
* use one template parameter and use IRTraits to get other used
types an type specific functions.
* remove the temporary "inline" keywords in previous refactor
patch.
* change the template function findEquivalencesFor to a regular
function. This function has a single caller with type of
PostDominatorTree. It's simpler to use the type directly
because MachinePostDominatorTree is not a derived type of
template DominatorTreeBase.
Differential Revision: https://reviews.llvm.org/D96981
Support reassociation for min/max. With that we should be able to transform min(min(a, b), c) -> min(min(a, c), b) if min(a, c) is already available.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D88287
In the existing logic, we look at the lifetime.start marker of each alloca, and check all uses of the alloca, to see if any pair of the lifetime marker and an use of alloca crosses suspension point.
This approach is unfortunately incorrect. An use of alloca does not need to be a direct use, but can be an indirect use through alias.
Only checking direct uses can miss cases where indirect uses are crossing suspension point.
This can be demonstrated in the newly added test case 007.
In the test case, both x and y are only directly used prior to suspend, but they are captured into an alias, merged through a PHINode (so they couldn't be materialized), and used after CoroSuspend.
If we only check whether the lifetime starts cross suspension points with direct uses, we will put the allocas to the stack, and then capture their addresses in the frame.
Instead of fixing it in D96441 and D96566, this patch takes a different approach which I think is better.
We still checks the lifetime info in the same way as before, but with two differences:
1. The collection of liftime.start is moved into AllocaUseVisitor to make the logic more concentrated.
2. When looking at lifetime.start and use pairs, we not only checks the direct uses as before, but in this patch we check all uses collected by AllocaUseVisitor, which would include all indirect uses through alias. This will make the analysis more accurate without throwing away the lifetime optimization.
Differential Revision: https://reviews.llvm.org/D96922
This extends b40fde062c for the especially non-standard
powi pattern. We want to avoid being completely wrong
on the negation-of-int-min corner case, so I'm adding
an extra FMF check for 'ninf' assuming that gives us
the flexibility to handle that possibility.
https://llvm.org/PR49147
This is a follow up to 22a52dfddc and a
revert of df763188c9.
With this change, we only skip cloning distinct nodes in
MDNodeMapper::mapDistinct if RF_ReuseAndMutateDistinctMDs, dropping the
no-longer-needed local helper `cloneOrBuildODR()`. Skipping cloning in
other cases is unsound and breaks CloneModule, which is why the textual
IR for PR48841 didn't pass previously. This commit adds the test as:
Transforms/ThinLTOBitcodeWriter/cfi-debug-info-cloned-type-references-global-value.ll
Cloning less often exposed a hole in subprogram cloning in
CloneFunctionInto thanks to df763188c9a1ecb1e7e5c4d4ea53a99fbb755903's
test ThinLTO/X86/Inputs/dicompositetype-unique-alias.ll. If a function
has a subprogram attachment whose scope is a DICompositeType that
shouldn't be cloned, but it has no internal debug info pointing at that
type, that composite type was being cloned. This commit plugs that hole,
calling DebugInfoFinder::processSubprogram from CloneFunctionInto.
As hinted at in 22a52dfddcefad4f275eb8ad1cc0e200074c2d8a's commit
message, I think we need to formalize ownership of metadata a bit more
so that ValueMapper/CloneFunctionInto (and similar functions) can deal
with cloning (or not) metadata in a more generic, less fragile way.
This fixes PR48841.
Differential Revision: https://reviews.llvm.org/D96734
Putting globals in a comdat for dead-stripping changes the semantic and
can potentially cause false negative odr violations at link time.
If odr indicators are used, we keep the comdat sections, as link time
odr violations will be dectected for the odr indicator symbols.
This fixes PR 47925
This reverts the revert commit 437f0bbcd5.
It adds a new toVPRecipeResult, which forces VPRecipeOrVPValueTy to be
constructed with a VPRecipeBase *. This should address ambiguous
constructor issues for recipe sub-types that also inherit from VPValue.
Previously there was no way to control how module destructors were emitted
by `ModuleAddressSanitizerPass`. However, we want language frontends (e.g. Clang)
to be able to decide how to emit these destructors (if at all).
This patch introduces the `AsanDtorKind` enum that represents the different ways
destructors can be emitted. There are currently only two valid ways to emit destructors.
* `Global` - Use `llvm.global_dtors`. This was the previous behavior and is the default.
* `None` - Do not emit module destructors.
The `ModuleAddressSanitizerPass` and the various wrappers around it have been updated
to take the `AsanDtorKind` as an argument.
The `-asan-destructor-kind=` command line argument has been introduced to make this
easy to test from `opt`. If this argument is specified it overrides the value passed
to the `ModuleAddressSanitizerPass` constructor.
Note that `AsanDtorKind` is not `bool` because we will introduce a new way to
emit destructors in a subsequent patch.
Note that `AsanDtorKind` is given its own header file because if it is declared
in `Transforms/Instrumentation/AddressSanitizer.h` it leads to compile error
(Module is ambiguous) when trying to use it in
`clang/Basic/CodeGenOptions.def`.
rdar://71609176
Differential Revision: https://reviews.llvm.org/D96571
This is a simple patch to update SimplifyCFG's passingValueIsAlwaysUndefined to inspect more attributes.
A new function `CallBase::isPassingUndefUB` checks attributes that imply noundef.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D97244
And delete the SmallPtrSetImpl overload.
While here, decrease inline element counts from 8 to 4. See D97128 for the choice.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D97257
While here, decrease inline element counts from 8 to 4. See D97128 for the choice.
Depends on D97128 (which added a new SmallVecImpl overload for collectUsedGlobalVariables).
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D97139
Iterating on `SmallPtrSet<GlobalValue *, 8>` with more than 8 elements
is not deterministic. Use a SmallVector instead because `Used` is guaranteed to contain unique elements.
While here, decrease inline element counts from 8 to 4. The number of
`llvm.used`/`llvm.compiler.used` elements is usually 0 or 1. For full
LTO/hybrid LTO, the number may be large, so we need to be careful.
According to tejohnson's analysis https://reviews.llvm.org/D97128#2582399 , 4 is
good for a large project with WholeProgramDevirt, when available_externally
vtables are placed in the llvm.compiler.used set.
Differential Revision: https://reviews.llvm.org/D97128
The fix in 3c4c205060 caused an assert in
the case of a pure virtual base class. In that case, the vTableFuncs
list on the summary will be empty, so we were hitting the new assert
that the linkage type was not available_externally.
In the case of pure virtual, we do not want to assert, and additionally
need to set VS so that we don't treat it conservatively and quit the
analysis of the type id early.
This exposed a pre-existing issue where we were not updating the vcall
visibility on pure virtual functions when whole program visibility was
specified. We were skipping updating the visibility on any global vars
that didn't have any vTableFuncs, which meant all pure virtual were not
updated, and the later analysis would block any devirtualization of
calls that had a type id used on those pure virtual vtables (see the
handling in the other code modified in this patch). Simply remove that
check. It will mean that we may update the vcall visibility on global
vars that aren't vtables, but that setting is ignored for any global
vars that didn't have type metadata anyway.
Added a new test case that asserted without removing the assert, and
that requires the other fixes in this patch (updateVCallVisibilityInIndex
and not skipping all vtables without virtual funcs) to get a successful
devirtualization with index-only WPD. I added cases to test hybrid and
regular LTO for completeness, although those already worked without the
fixes here.
With this final fix, a clang multistage bootstrap with WPD builds and
runs all tests successfully.
Differential Revision: https://reviews.llvm.org/D97126
Under certain (currently unknown) conditions, llvm-profdata is outputting
profiles that have two consecutive entries in the MemOPSize section for the
value 0. This causes the PGOMemOPSizeOpt pass to output an invalid switch
instruction with two cases for 0. As mentioned, we’re not quite sure what’s
causing this to happen, but this patch prevents llvm-profdata from outputting a
profile that has this problem and gives an error with a request for a
reproducible.
Differential Revision: https://reviews.llvm.org/D92074
Generalize the return value of tryToCreateWidenRecipe to return either a
newly create recipe or an existing VPValue. Use this to avoid creating
unnecessary VPBlendRecipes.
Fixes PR44800.
The new intrinsic replaces the size in one specified AsyncFunctionPointer with
the size in another. This ability is necessary for functions which merely
forward to async functions such as those defined for partial applications.
Reviewed By: aschwaighofer
Differential Revision: https://reviews.llvm.org/D97229
As a followup to D95291, getOperandsScalarizationOverhead was still
using a VF as a vector factor if the arguments were scalar, and would
assert on certain matrix intrinsics with differently sized vector
arguments. This patch removes the VF arg, instead passing the Types
through directly. This should allow it to more accurately compute the
cost without having to guess at which operands will be vectorized,
something difficult with more complex intrinsics.
This adjusts one SVE test as it is now calling the wrong intrinsic vs
veccall. Without invalid InstructCosts the cost of the scalarized
intrinsic is too low. This should get fixed when the cost of
scalarization is accounted for with scalable types.
Differential Revision: https://reviews.llvm.org/D96287
getIntrinsicInstrCost takes a IntrinsicCostAttributes holding various
parameters of the intrinsic being costed. It can either be called with a
scalar intrinsic (RetTy==Scalar, VF==1), with a vector instruction
(RetTy==Vector, VF==1) or from the vectorizer with a scalar type and
vector width (RetTy==Scalar, VF>1). A RetTy==Vector, VF>1 is considered
an error. Both of the vector modes are expected to be treated the same,
but because this is confusing many backends end up getting it wrong.
Instead of trying work with those two values separately this removes the
VF parameter, widening the RetTy/ArgTys by VF used called from the
vectorizer. This keeps things simpler, but does require some other
modifications to keep things consistent.
Most backends look like this will be an improvement (or were not using
getIntrinsicInstrCost). AMDGPU needed the most changes to keep the code
from c230965ccf working. ARM removed the fix in
dfac521da1, webassembly happens to get a fixup for an SLP cost
issue and both X86 and AArch64 seem to now be using better costs from
the vectorizer.
Differential Revision: https://reviews.llvm.org/D95291
The **IsGuaranteedLoopInvariant** function is making sure to check if the
incoming pointer is guaranteed to be loop invariant, therefore I think
the case where the pointer is defined in the entry block of a function
automatically guarantees the pointer to be loop invariant, as the entry
block of a function cannot have predecessors or be part of a loop.
I implemented this small patch and tested it using
**ninja check-llvm-unit** and **ninja check-llvm**. I added a contained test
file that shows the problem and used **opt -O3 -debug** on it to make sure
the case is not currently handled (in fact the debug log is showing that
the DSE pass is bailing out when testing if the killer store is able to
clobber the dead store).
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D96979
This is a patch to explicitly mark the size parameter of allocator functions like malloc/realloc/... as noundef.
For C/C++: undef can be created from reading an uninitialized variable or padding.
Calling a function with uninitialized variable is already UB.
Calling malloc with padding value is.. something that's not expected. Padding bits may appear in a coerced aggregate, which doesn't apply to malloc's size.
Therefore, malloc's size can be marked as noundef.
For transformations that introduce malloc/realloc/..: I ran LLVM unit tests with an updated Alive2 semantics, and found no regression, so it seems okay.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D97045
__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.
The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.
Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.
Differential Revision: https://reviews.llvm.org/D96757
Pointer operand of scatter loads does not remain scalar in the tree (it
gest vectorized) and thus must not be marked as the scalar that remains
scalar in vectorized form.
Differential Revision: https://reviews.llvm.org/D96818
ICMP_NE predicates cannot be directly represented as constraint. But we
can use ICMP_UGT instead ICMP_NE for %x != 0.
See https://alive2.llvm.org/ce/z/XlLCsW
If the call is readnone, then there may not be any MemoryAccess
associated with the call. Bail out in that case.
This fixes the issue reported at
https://reviews.llvm.org/D94376#2578312.
When cloning instructions during jump threading, also clone and
adapt any declared scopes. This is primarily important when
threading loop exits, because we'll end up with two dominating
scope declarations in that case (at least after additional loop
rotation). This addresses a loose thread from
https://reviews.llvm.org/rG2556b413a7b8#975012.
Differential Revision: https://reviews.llvm.org/D97154
This patch extends VPWidenPHIRecipe to manage pairs of incoming
(VPValue, VPBasicBlock) in the VPlan native path. This is made possible
because we now directly manage defined VPValues for recipes.
By keeping both the incoming value and block in the recipe directly,
code-generation in the VPlan native path becomes independent of the
predecessor ordering when fixing up non-induction phis, which currently
can cause crashes in the VPlan native path.
This fixes PR45958.
Reviewed By: sguggill
Differential Revision: https://reviews.llvm.org/D96773
__start_/__stop_ references retain C identifier name sections such as
__llvm_prf_*. Putting these into a section group disables this logic.
The ELF section group semantics ensures that group members are retained
or discarded as a unit. When a function symbol is discarded, this allows
allows linker to discard counters, data and values associated with that
function symbol as well.
Note that `noduplicates` COMDAT is lowered to zero-flag section group in
ELF. We only set this for functions that aren't already in a COMDAT and
for those that don't have available_externally linkage since we already
use regular COMDAT groups for those.
Differential Revision: https://reviews.llvm.org/D96757
FindAvailableLoadedValue() accepts an iterator by reference. If no
available value is found, then the iterator will either be left
at a clobbering instruction or the beginning of the basic block.
This allows using FindAvailableLoadedValue() across multiple blocks.
If this functionality is not needed, as is the case in InstCombine,
then we can use a much more efficient implementation: First try
to find an available value, and only perform clobber checks if
we actually found one. As this function only looks at a very small
number of instructions (6 by default) and usually doesn't find an
available value, this saves many expensive alias analysis queries.
Currently, if there is a module that contains a strong definition of
a global variable and a module that has both a weak definition for
the same global and a reference to it, it may result in an undefined symbol error
while linking with ThinLTO.
It happens because:
* the strong definition become internal because it is read-only and can be imported;
* the weak definition gets replaced by a declaration because it's non-prevailing;
* the strong definition failed to be imported because the destination module
already contains another definition of the global yet this def is non-prevailing.
The patch adds a check to computeImportForReferencedGlobals() that allows
considering a global variable for being imported even if the module contains
a definition of it in the case this def has an interposable linkage type.
Note that currently the check is based only on the linkage type
(and this seems to be enough at the moment), but it might be worth to account
the information whether the def is prevailing or not.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D95943
Follow-up to:
D96648 / b40fde062
...for the special-case base calls.
From the earlier commit:
This is unusual in the general (non-reciprocal) case because we need
an extra instruction, but that should be better for general FP
reassociation and codegen. We conservatively check for "arcp" FMF
here as we do with existing fdiv folds, but it is not strictly
necessary to have that.
Refines the fix in 3c4c205060 to only
put globals whose defs were cloned into the split regular LTO module
on the cloned llvm*.used globals. This avoids an issue where one of the
attached values was a local that was promoted in the original module
after the module was cloned. We only need to have the values defined in
the new module on those globals.
Fixes PR49251.
Differential Revision: https://reviews.llvm.org/D97013
recognizeBSwapOrBitReverseIdiom + collectBitParts have pattern matching to bail out early if a bswap/bitreverse pattern isn't possible - we should be able to rely on this instead without any notable change in compile time.
This is part of a cleanup towards letting matchBSwapOrBitReverse /recognizeBSwapOrBitReverseIdiom use 'root' instructions that aren't ORs (FSHL/FSHRs in particular which can be prematurely created).
Differential Revision: https://reviews.llvm.org/D97056
I think we can use here same logic as for nonnull.
strlen(X) - X must be noundef => valid pointer.
for libcalls with size arg, we add noundef only if size is known and greater than 0 - so pointers must be noundef (valid ones)
Reviewed By: jdoerfert, aqjune
Differential Revision: https://reviews.llvm.org/D95122
In https://reviews.llvm.org/rG5fb65c02ca5e91e7e1a00e0efdb8edc899f3e4b9,
We use 0 count value profile to memorize which target has been promoted
and prevent repeated ICP for the same target, so we delete PromotedInsns.
However, I found the implementation in the patch has some shortcomings
to be fixed otherwise there will still be repeated ICP. So I add
PromotedInsns back temorarily. Will remove it after I get a thorough fix.
This enables use of MemorySSA instead of MemDep in MemCpyOpt. To
allow this without significant compile-time impact, the MemCpyOpt
pass is moved directly before DSE (in the cases where this was not
already the case), which allows us to reuse the existing MemorySSA
analysis.
Unlike the MemDep-based implementation, the MemorySSA-based MemCpyOpt
can also perform simple optimizations across basic blocks.
Differential Revision: https://reviews.llvm.org/D94376
Now that all state for generated instructions is managed directly in
VPTransformState, VPCallBack is no longer needed. This patch updates the
last use of `getOrCreateScalarValue` to instead manage the value
directly in VPTransformState and removes VPCallback.
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D95383
In both ADCE and BDCE (via DemandedBits) we should not remove
instructions that are not guaranteed to return. This issue was
pointed out by fhahn in the recent llvm-dev thread.
Differential Revision: https://reviews.llvm.org/D96993
This moves the willReturn() helper from CallBase to Instruction,
so that it can be used in a more generic manner. This will make
it easier to fix additional passes (ADCE and BDCE), and will give
us one place to change if additional instructions should become
non-willreturn (e.g. there has been talk about handling volatile
operations this way).
I have also included the IntrinsicInst workaround directly in
here, so that it gets applied consistently. (As such this change
is not entirely NFC -- FuncAttrs will now use this as well.)
Differential Revision: https://reviews.llvm.org/D96992
As discussed on the RFC [0], I am sharing the set of patches that
enables checking of original Debug Info metadata preservation in
optimizations. The proof-of-concept/proposal can be found at [1].
The implementation from the [1] was full of duplicated code,
so this set of patches tries to merge this approach into the existing
debugify utility.
For example, the utility pass in the original-debuginfo-check
mode could be invoked as follows:
$ opt -verify-debuginfo-preserve -pass-to-test sample.ll
Since this is very initial stage of the implementation,
there is a space for improvements such as:
- Add support for the new pass manager
- Add support for metadata other than DILocations and DISubprograms
[0] https://groups.google.com/forum/#!msg/llvm-dev/QOyF-38YPlE/G213uiuwCAAJ
[1] https://github.com/djolertrk/llvm-di-checker
Differential Revision: https://reviews.llvm.org/D82545
The test that was failing is now forced to use the old PM.
As discussed in D94834, we don't really need to do complicated analysis. It's safe to just drop the tail call attribute.
Differential Revision: https://reviews.llvm.org/D96926
Found a problem in indirect call promotion in sample loader pass. Currently
if an indirect call is promoted for a target, and if the parent function is
inlined into some other function, the indirect call can be promoted for the
same target again. That is redundent which can harm performance and can cause
excessive compile time in some extreme case.
The patch fixes the issue. If a target is promoted for an indirect call, the
patch will write ICP metadata with the target call count being set to 0.
In the later ICP in sample profile loader, if it sees a target has 0 count
for an indirect call, it knows the target has been promoted and won't do
indirect call promotion for the indirect call.
The fix brings 0.1~0.2% performance on our search benchmark.
Differential Revision: https://reviews.llvm.org/D96806
With CSSPGO all indirect call targets are counted torwards the original indirect call site in the profile, including both inlined and non-inlined targets. Therefore no need to look for callee entry counts. This also fixes the issue where callee entry count doesn't match callsite count due to the nature of CS sampling.
I'm also cleaning up the orginal code that called `findIndirectCallFunctionSamples` just to compute the sum, the return value of which was disgarded.
Reviewed By: wmi, wenlei
Differential Revision: https://reviews.llvm.org/D96990
We can always look through single-argument (LCSSA) phi nodes when
performing alias analysis. getUnderlyingObject() already does this,
but stripPointerCastsAndInvariantGroups() does not. We still look
through these phi nodes with the usual aliasPhi() logic, but
sometimes get sub-optimal results due to the restrictions on value
equivalence when looking through arbitrary phi nodes. I think it's
generally beneficial to keep the underlying object logic and the
pointer cast stripping logic in sync, insofar as it is possible.
With this patch we get marginally better results:
aa.NumMayAlias | 5010069 | 5009861
aa.NumMustAlias | 347518 | 347674
aa.NumNoAlias | 27201336 | 27201528
...
licm.NumPromoted | 1293 | 1296
I've renamed the relevant strip method to stripPointerCastsForAliasAnalysis(),
as we're past the point where we can explicitly spell out everything
that's getting stripped.
Differential Revision: https://reviews.llvm.org/D96668
This fixes https://bugs.llvm.org/show_bug.cgi?id=49185
When `NDEBUG` is not set, `LPMUpdater` checks if the added loops have the same parent loop as the current one in `addSiblingLoops`.
If multiple loop passes are executed through `LoopPassManager`, `U.ParentL` will be the same across all passes.
However, the parent loop might change after running a loop pass, resulting in assertion failures in subsequent passes.
This patch resets `U.ParentL` after running individual loop passes in `LoopPassManager`.
Reviewed By: asbirlea, ychen
Differential Revision: https://reviews.llvm.org/D96727
This patch simply implements the documented UB of the current nofree attributes as specified. It doesn't try to be fancy about inference (yet), it just implements the cases already specified and inferred.
Note: When this lands, it may expose miscompiles. If so, please revert and provide a test case. It's likely the bug is in the existing inference code and without a relatively complete test case, it will be hard to debug.
Differential Revision: https://reviews.llvm.org/D96349
As discussed on the RFC [0], I am sharing the set of patches that
enables checking of original Debug Info metadata preservation in
optimizations. The proof-of-concept/proposal can be found at [1].
The implementation from the [1] was full of duplicated code,
so this set of patches tries to merge this approach into the existing
debugify utility.
For example, the utility pass in the original-debuginfo-check
mode could be invoked as follows:
$ opt -verify-debuginfo-preserve -pass-to-test sample.ll
Since this is very initial stage of the implementation,
there is a space for improvements such as:
- Add support for the new pass manager
- Add support for metadata other than DILocations and DISubprograms
[0] https://groups.google.com/forum/#!msg/llvm-dev/QOyF-38YPlE/G213uiuwCAAJ
[1] https://github.com/djolertrk/llvm-di-checker
Differential Revision: https://reviews.llvm.org/D82545
Floating point conversions inside vectorized loops have performance
implications but are very subtle. The user could specify a floating
point constant, or call a function without realizing that it will
force a change in the vector width. An example of this behaviour is
seen in https://godbolt.org/z/M3nT6c . The vectorizer should indicate
when this happens becuase it is most likely unintended behaviour.
This patch adds a simple check for this behaviour by following floating
point stores in the original loop and checking if a floating point
conversion operation occurs.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D95539
This adds an internal option -wholeprogramdevirt-check which if enabled
will guard each devirtualization with a runtime check against the
expected target, and an invocation of a debug trap if the check fails.
This is useful for debugging WPD failures involving undefined behavior
(e.g. casting to another class type not in the inheritance chain).
Differential Revision: https://reviews.llvm.org/D95969
Apply the patch for the third time after fixing buildbot failures.
Refactor SampleProfile.cpp to use the core code in CodeGen.
The main changes are:
(1) Move SampleProfileLoaderBaseImpl class to a header file.
(2) Split SampleCoverageTracker to a head file and a cpp file.
(3) Move the common codes (common options and callsiteIsHot())
to the common cpp file.
(4) Add inline keyword to avoid duplicated symbols -- they will
be removed later when the class is changed to a template.
Differential Revision: https://reviews.llvm.org/D96455
Adds a lld test for a case that the handling added for dynamically
exported symbols in 1487747e99 already
fixes. Because isExportDynamic returns true when the symbol is
SharedKind with default visibility, it will treat as dynamically
exported and block devirtualization when the definition of a vtable
comes from a shared library. This is desireable as it is dangerous to
devirtualize in that case, since there could be hidden overrides in the
shared library. Typically that happens when the shared library header
contains available externally definitions, which applications can
override. An example is std::error_category, which is overridden in LLVM
and causing failures after a self build with WPD enabled, because
libstdc++ contains hidden overrides of the virtual base class methods.
The regular LTO case in the new test already worked, but there are
2 fixes in this patch needed for the index-only case and the hybrid
LTO case. For the index-only case, WPD should not simply ignore
available externally vtables. A follow on fix will be made to clang to
emit type metadata for those vtables, which the new test is modeling.
For the hybrid case, we need to ensure when the module is split that any
llvm.*used globals are cloned to the regular LTO split module so
available externally vtable definitions are not prematurely deleted.
Another follow on fix will add the equivalent gold test, which requires
a small fix to the plugin to treat symbols in dynamic libraries the same
way lld already is.
Differential Revision: https://reviews.llvm.org/D96721
Revert "[SampleFDO] Add missing #includes to unbreak modules build after D96455"
This reverts commit c73cbf218a.
Revert "[SampleFDO] Fix MSVC "namespace uses itself" warning (NFC)"
This reverts commit a23e6b321c.
Revert "[SampleFDO] Reapply: Refactor SampleProfile.cpp"
This reverts commit 6fd5ccff72.
Still seeing link failures when building llc (or other tools), due to
the new SampleProfileLoaderBaseImpl.h containing definitions that get
duplicated across multiple TU's.
```
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::findEquivalenceClasses(llvm::Function&)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::buildEdges(llvm::Function&)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::computeDominanceAndLoopInfo(llvm::Function&)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::getFunctionLoc(llvm::Function&)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::getBlockWeight(llvm::BasicBlock const*)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::printBlockWeight(llvm::raw_ostream&, llvm::BasicBlock const*) const' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::printBlockEquivalence(llvm::raw_ostream&, llvm::BasicBlock const*)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
duplicate symbol 'llvm::SampleProfileLoaderBaseImpl::printEdgeWeight(llvm::raw_ostream&, std::__1::pair<llvm::BasicBlock const*, llvm::BasicBlock const*>)' in:
tools/llc/CMakeFiles/llc.dir/llc.cpp.o
lib/libLLVMInstCombine.a(InstCombineVectorOps.cpp.o)
```
SROA does not correctly account for offsets in TBAA/TBAA struct metadata.
This patch creates functionality for generating new MD with the corresponding
offset and updates SROA to use this functionality.
Differential Revision: https://reviews.llvm.org/D95826
This is the preliminary patch of converting `LoopInterchange` pass to a loop-nest pass and has no intended functional change.
Changes that are not loop-nest related are split to D96650.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D96644
This adds a new flag -lsr-preferred-addressing-mode to override the target's
preferred addressing mode. It replaces flag -lsr-backedge-indexing, which is
equivalent to preindexed addressing that is one of the options that
-lsr-preferred-addressing-mode accepts.
Differential Revision: https://reviews.llvm.org/D96855
As discussed in:
https://llvm.org/PR49179
...this pattern shows up in library code.
There are several potential generalizations as noted,
but we need to be careful that we get FP special-values
right, and it's not clear how much variation we should
expect to see from this exact idiom.
This is a follow up D96600 and cleans up most calls to
getPreferredAddresingMode. I.e., we really don't need to query the same things
again and again, but get the preferred addressing mode once for each loop. So
this should be a lot friendlier for compile times, especially if we start
implementing getPreferredAddresingMode.
Differential Revision: https://reviews.llvm.org/D96772
Reapply patch after fixing buildbot failure.
Refactor SampleProfile.cpp to use the core code in CodeGen.
The main changes are:
(1) Move SampleProfileLoaderBaseImpl class to a header file.
(2) Split SampleCoverageTracker to a head file and a cpp file.
(3) Move the common codes (common options and callsiteIsHot())
to the common cpp file.
Differential Revision: https://reviews.llvm.org/D96455
This reverts commit 310b35304c.
The build is broken with -DBUILD_SHARED_LIBS=ON :
lib/ProfileData/CMakeFiles/LLVMProfileData.dir/SampleProfileLoaderBaseUtil.cpp.o: In function `llvm::sampleprofutil::callsiteIsHot(llvm::sampleprof::FunctionSamples const*, llvm::ProfileSummaryInfo*, bool)':
SampleProfileLoaderBaseUtil.cpp:(.text._ZN4llvm14sampleprofutil13callsiteIsHotEPKNS_10sampleprof15FunctionSamplesEPNS_18ProfileSummaryInfoEb+0x1a): undefined reference to `llvm::ProfileSummaryInfo::isColdCount(unsigned long) const'
SampleProfileLoaderBaseUtil.cpp:(.text._ZN4llvm14sampleprofutil13callsiteIsHotEPKNS_10sampleprof15FunctionSamplesEPNS_18ProfileSummaryInfoEb+0x28): undefined reference to `llvm::ProfileSummaryInfo::isHotCount(unsigned long) const'
...
Refactor SampleProfile.cpp to use the core code in CodeGen.
The main changes are:
(1) Move SampleProfileLoaderBaseImpl class to a header file.
(2) Split SampleCoverageTracker to a head file and a cpp file.
(3) Move the common codes (common options and callsiteIsHot())
to the common cpp file.
Differential Revision: https://reviews.llvm.org/D96455
Also don't call function to update the call graph if there are no
clones. The function will fail.
rdar://74277860
Differential Revision: https://reviews.llvm.org/D96620
This is a split patch of D96644.
Explicitly pass both `InnerLoop` and `OuterLoop` to function `processLoop` to remove the need to swap elements in loop list and allow making loop list an `ArrayRef`.
Also, fix inconsistent spellings of `OuterLoopId` and `Inner Loop Id` in debug log.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D96650
This patch enables scalable vectorization of loops with integer/fast reductions, e.g:
```
unsigned sum = 0;
for (int i = 0; i < n; ++i) {
sum += a[i];
}
```
A new TTI interface, isLegalToVectorizeReduction, has been added to prevent
reductions which are not supported for scalable types from vectorizing.
If the reduction is not supported for a given scalable VF,
computeFeasibleMaxVF will fall back to using fixed-width vectorization.
Reviewed By: david-arm, fhahn, dmgreen
Differential Revision: https://reviews.llvm.org/D95245
This patch changes costAndCollectOperands to use InstructionCost for
accumulated cost values.
isHighCostExpansion will return true if the cost has exceeded the budget.
Reviewed By: CarolineConcatto, ctetreau
Differential Revision: https://reviews.llvm.org/D92238
This patch updates codegen to use VPValues to manage the generated
scalarized instructions.
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D92285
This commit fixes how metadata is handled in CloneModule to be sound,
and improves how it's handled in CloneFunctionInto (although the latter
is still awkward when called within a module).
Ruiling Song pointed out in PR48841 that CloneModule was changed to
unsoundly use the RF_ReuseAndMutateDistinctMDs flag (renamed in
fa35c1f80f for clarity). This flag papered
over a crash caused by other various changes made to CloneFunctionInto
over the past few years that made it unsound to use cloning between
different modules.
(This commit partially addresses PR48841, fixing the repro from
preprocessed source but not textual IR. MDNodeMapper::mapDistinctNode
became unsound in df763188c9 and this
commit does not address that regression.)
RF_ReuseAndMutateDistinctMDs is designed for the IRMover to use,
avoiding unnecessary clones of all referenced metadata when linking
between modules (with IRMover, the source module is discarded after
linking). It never makes sense to use when you're not discarding the
source. This commit drops its incorrect use in CloneModule.
Sadly, the right thing to do with metadata when cloning a function is
complicated, and this patch doesn't totally fix it.
The first problem is that there are two different types of referenceable
metadata and it's not obvious what to with one of them when remapping.
- `!0 = !{!1}` is metadata's version of a constant. Programatically it's
called "uniqued" (probably a better term would be "constant") because,
like `ConstantArray`, it's stored in uniquing tables. Once it's
constructed, it's illegal to change its arguments.
- `!0 = distinct !{!1}` is a bit closer to a global variable. It's legal
to change the operands after construction.
What should be done with distinct metadata when cloning functions within
the same module?
- Should new, cloned nodes be created?
- Should all references point to the same, old nodes?
The answer depends on whether that metadata is effectively owned by a
function.
And that's the second problem. Referenceable metadata's ownership model
is not clear or explicit. Technically, it's all stored on an
LLVMContext. However, any metadata that is `distinct`, that transitively
references a `distinct` node, or that transitively references a
GlobalValue is specific to a Module and is effectively owned by it. More
specifically, some metadata is effectively owned by a specific Function
within a module.
Effectively function-local metadata was introduced somewhere around
c10d0e5ccd, which made it illegal for two
functions to share a DISubprogram attachment.
When cloning a function within a module, you need to clone the
function-local debug info and suppress cloning of global debug info (the
status quo suppresses cloning some global debug info but not all). When
cloning a function to a new/different module, you need to clone all of
the debug info.
Here's what I think we should do (eventually? soon? not this patch
though):
- Distinguish explicitly (somehow) between pure constant metadata owned
by the LLVMContext, global metadata owned by the Module, and local
metadata owned by a GlobalValue (such as a function).
- Update CloneFunctionInto to trigger cloning of all "local" metadata
(only), perhaps by adding a bit to RemapFlag. Alternatively, split
out a separate function CloneFunctionMetadataInto to prime the
metadata map that callers are updated to call ahead of time as
appropriate.
Here's the somewhat more isolated fix in this patch:
- Converted the `ModuleLevelChanges` parameter to `CloneFunctionInto` to
an enum called `CloneFunctionChangeType` that is one of
LocalChangesOnly, GlobalChanges, DifferentModule, and ClonedModule.
- The code maintaining the "functions uniquely own subprograms"
invariant is now only active in the first two cases, where a function
is being cloned within a single module. That's necessary because this
code inhibits cloning of (some) "global" metadata that's effectively
owned by the module.
- The code maintaining the "all compile units must be explicitly
referenced by !llvm.dbg.cu" invariant is now only active in the
DifferentModule case, where a function is being cloned into a new
module in isolation.
- CoroSplit.cpp's call to CloneFunctionInto in CoroCloner::create
uses LocalChangeOnly, since fa635d730f
only set `ModuleLevelChanges` to trigger cloning of local metadata.
- CloneModule drops its unsound use of RF_ReuseAndMutateDistinctMDs
and special handling of !llvm.dbg.cu.
- Fixed some outdated header docs and left a couple of FIXMEs.
Differential Revision: https://reviews.llvm.org/D96531
Loop canonicalization may end up deleting blocks from CFG. And
Scalar Evolution may still keep cached referenced to those blocks
unless updated properly.
This refactors shouldFavorPostInc() and shouldFavorBackedgeIndex() into
getPreferredAddressingMode() so that we have one interface to steer LSR in
generating the preferred addressing mode.
Differential Revision: https://reviews.llvm.org/D96600
This is unusual in the general (non-reciprocal) case because we need
an extra instruction, but that should be better for general FP
reassociation and codegen. We conservatively check for "arcp" FMF
here as we do with existing fdiv folds, but it is not strictly
necessary to have that.
This is part of solving:
https://llvm.org/PR49147
(The powi variant potentially has a different constraint.)
Differential Revision: https://reviews.llvm.org/D96648
This patch fixes pr48832 by correctly generating the mask when a poison value is involved.
Consider this CFG (which is a part of the input):
```
for.body: ; preds = %for.cond
br i1 true, label %cond.false, label %land.rhs
land.rhs: ; preds = %for.body
br i1 poison, label %cond.end, label %cond.false
cond.false: ; preds = %for.body, %land.rhs
br label %cond.end
cond.end: ; preds = %land.rhs, %cond.false
%cond = phi i32 [ 0, %cond.false ], [ 1, %land.rhs ]
```
The path for.body -> land.rhs -> cond.end should be taken when 'select i1 false, i1 poison, i1 false' holds (which means it's never taken); but VPRecipeBuilder::createEdgeMask was emitting 'and i1 false, poison' instead.
The former one successfully blocks poison propagation whereas the latter one doesn't, making the condition poison and thus causing the miscompilation.
SimplifyCFG has a similar bug (which didn't expose a real-world bug yet), and a patch for this is also ongoing (see https://reviews.llvm.org/D95026).
Reviewed By: bjope
Differential Revision: https://reviews.llvm.org/D95217
Instcombine will convert the nonnull and alignment assumption that use the boolean condtion
to an assumption that uses the operand bundles when knowledge retention is enabled.
Differential Revision: https://reviews.llvm.org/D82703
Perform DSOLocal propagation within summary list of every GV. This
avoids the repeated query of this information during function
importing.
Differential Revision: https://reviews.llvm.org/D96398
This allows for suspend point specific resume function types.
Return values from a suspend point can therefore be modelled as
arguments to the resume function. Allowing for directly passed return
types.
Differential Revision: https://reviews.llvm.org/D96136
explicitly emitting retainRV or claimRV calls in the IR
Background:
This fixes a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.
https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
What this patch does to fix the problem:
- The front-end adds operand bundle "clang.arc.attachedcall" to calls,
which indicates the call is implicitly followed by a marker
instruction and an implicit retainRV/claimRV call that consumes the
call result. In addition, it emits a call to
@llvm.objc.clang.arc.noop.use, which consumes the call result, to
prevent the middle-end passes from changing the return type of the
called function. This is currently done only when the target is arm64
and the optimization level is higher than -O0.
- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
with the operand bundle in the IR and removes the inserted calls after
processing the function.
- ARC contract pass emits retainRV/claimRV calls after the call with the
operand bundle. It doesn't remove the operand bundle on the call since
the backend needs it to emit the marker instruction. The retainRV and
claimRV calls are emitted late in the pipeline to prevent optimization
passes from transforming the IR in a way that makes it harder for the
ARC middle-end passes to figure out the def-use relationship between
the call and the retainRV/claimRV calls (which is the cause of
PR31925).
- The function inliner removes an autoreleaseRV call in the callee if
nothing in the callee prevents it from being paired up with the
retainRV/claimRV call in the caller. It then inserts a release call if
claimRV is attached to the call since autoreleaseRV+claimRV is
equivalent to a release. If it cannot find an autoreleaseRV call, it
tries to transfer the operand bundle to a function call in the callee.
This is important since the ARC optimizer can remove the autoreleaseRV
returning the callee result, which makes it impossible to pair it up
with the retainRV/claimRV call in the caller. If that fails, it simply
emits a retain call in the IR if retainRV is attached to the call and
does nothing if claimRV is attached to it.
- SCCP refrains from replacing the return value of a call with a
constant value if the call has the operand bundle. This ensures the
call always has at least one user (the call to
@llvm.objc.clang.arc.noop.use).
- This patch also fixes a bug in replaceUsesOfNonProtoConstant where
multiple operand bundles of the same kind were being added to a call.
Future work:
- Use the operand bundle on x86-64.
- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls with the operand bundles.
rdar://71443534
Differential Revision: https://reviews.llvm.org/D92808
Changes `getScalarizationOverhead` to return an invalid cost for scalable VFs
and adds some simple tests for loops containing a function for which
there is a vectorized variant available.
Reviewed By: david-arm
Differential Revision: https://reviews.llvm.org/D96356
The vector reduction intrinsics started life as experimental ops, so backend support
was lacking. As part of promoting them to 1st-class intrinsics, however, codegen
support was added/improved:
D58015
D90247
So I think it is safe to now remove this complication from IR.
Note that we still have an IR-level codegen expansion pass for these as discussed
in D95690. Removing that is another step in simplifying the logic. Also note that
x86 was already unconditionally forming reductions in IR, so there should be no
difference for x86.
I spot checked a couple of the tests here by running them through opt+llc and did
not see any asm diffs.
If we do find functional differences for other targets, it should be possible
to (at least temporarily) restore the shuffle IR with the ExpandReductions IR
pass.
Differential Revision: https://reviews.llvm.org/D96552
The individual recipes have been updated to manage their operands using
VPUser a while back. Now that the transition is done, we can instead
make VPRecipeBase a VPUser and get rid of the toVPUser helper.
This patch changes the VecDesc struct to use ElementCount
instead of an unsigned VF value, in preparation for
future work that adds support for vectorized versions of
math functions using scalable vectors. Since all I'm doing
in this patch is switching the type I believe it's a
non-functional change. I changed getWidestVF to now return
both the widest fixed-width and scalable VF values, but
currently the widest scalable value will be zero.
Differential Revision: https://reviews.llvm.org/D96011
Functions are currently processed by the sample profiler loader in a top-down order defined by the static call graph. The order is being adjusted to be a top-down order based on the input context-sensitive profile. One benefit is that the processing order of caller and callee in one SCC would follow the context order in the profile to favor more inlining. Another benefit is that the processing order of caller and callee through an indirect call (which is not on the static call graph) can be honored which in turn allows for more inlining.
The profile top-down order for SCC is also extended to support non-CS profiles.
Two switches `-mllvm -use-profile-indirect-call-edges` and `-mllvm -use-profile-top-down-order` are being introduced.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D95988
This reverts commit b7d870eae7 and the
subsequent fix "[Polly] Fix build after AssumptionCache change (D96168)"
(commit e6810cab09).
It caused indeterminism in the output, such that e.g. the
polly-x86_64-linux buildbot failed accasionally.
This will be needed in the loop-vectorizer where the minimum VF
requested may be a scalable VF. getMinimumVF now takes an additional
operand 'IsScalableVF' that indicates whether a scalable VF is required.
Reviewed By: kparzysz, rampitec
Differential Revision: https://reviews.llvm.org/D96020
This patch is NFC and changes occurrences of `unsigned Width`
and `unsigned i` to work on type ElementCount instead.
This patch is a preparatory patch with the ultimate goal of making
`computeMaxVF()` return both a max fixed VF and a max scalable VF,
so that `selectVectorizationFactor()` can pick the most cost-effective
vectorization factor.
Reviewed By: david-arm
Differential Revision: https://reviews.llvm.org/D96019
Rename the `RF_MoveDistinctMDs` flag passed into `MapValue` and
`MapMetadata` to `RF_ReuseAndMutateDistinctMDs` in order to more
precisely describe its effect and clarify the header documentation.
Found this while helping to investigate PR48841, which pointed out an
unsound use of the flag in `CloneModule()`. For now I've just added a
FIXME there, but I'm hopeful that the new (more precise) name will
prevent other similar errors.
Break SampleProfileLoader into to a base and a derived class.
Base class (SampleProfileLoaderBaseImpl) includes the common
code for IR and MachineIR (CodeGen) sample loader.
It will be templatelized in the later patch.
Inline and Probe related code will remain in the derived class of
SampleProfileLoader and stays in SampleProfile.cpp.
We need to refactor some functions:
(1) getInstWeight() to enable the code sharing -- put the core into
getInstWeightImpl().
(2) emitAnnotation() and propagateWeights() to carve out the code
specific to SampleProfileLoader.
(3) make getInstWeight() and findFunctionSamples() virtual and override
in SampleProfileLoader as they need to access the fields in the derived
class.
Differential Revision: https://reviews.llvm.org/D95832
The IR/MIR pseudo probe intrinsics don't get materialized into real machine instructions and therefore they don't incur runtime cost directly. However, they come with indirect cost by blocking certain optimizations. Some of the blocking are intentional (such as blocking code merge) for better counts quality while the others are accidental. This change unblocks perf-critical optimizations that do not affect counts quality. They include:
1. IR InstCombine, sinking load operation to shorten lifetimes.
2. MIR LiveRangeShrink, similar to #1
3. MIR TwoAddressInstructionPass, i.e, opeq transform
4. MIR function argument copy elision
5. IR stack protection. (though not perf-critical but nice to have).
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D95982
This is a special-case multiply that replicates bits of
the source operand. We need this fold to avoid regression
if we make canonicalization to `mul` more aggressive for
shl+or patterns.
I did not see a way to make Alive generalize the bit width
condition for even-number-of-bits only, but an example of
the proof is:
Name: i32
Pre: isPowerOf2(C1 - 1) && log2(C1) == C2 && (C2 * 2 == width(C2))
%m = mul nuw i32 %x, C1
%t = lshr i32 %m, C2
=>
%t = and i32 %x, C1 - 2
Name: i14
%m = mul nuw i14 %x, 129
%t = lshr i14 %m, 7
=>
%t = and i14 %x, 127
https://rise4fun.com/Alive/e52
This patch is NFC and changes occurrences of `unsigned MaxVectorSize`
to work on type ElementCount.
This patch is a preparatory patch with the ultimate goal of making
`computeMaxVF()` return both a max fixed VF and a max scalable VF,
so that `selectVectorizationFactor()` can pick the most cost-effective
vectorization factor.
Reviewed By: kmclaughlin
Differential Revision: https://reviews.llvm.org/D96018
VP blocks keep track of a condition, which is a VPValue. This patch
updates VPBlockBase to manage the value using VPUser, so
replaceAllUsesWith properly updates the condition bit as well.
This is required to enable VP2VP transformations and it helps with
simplifying some of the code required to manage condition bits.
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D95382
This was reported as PR49104. The reproducer uses varargs but the issue
is the same, we know an argument is dead but can't change the signature
for some reason. The PR49104 situation was: We are in an CG-SCC
traversal and we remove all the uses of an argument and proof it thereby
dead. However, if we do not remove the argument, via signature rewrite,
we need to ensure that the `undef` we introduce at the call site doesn't
clash with a `noundef` attribute.
Instcombine will convert the nonnull and alignment assumption that use the boolean condtion
to an assumption that uses the operand bundles when knowledge retention is enabled.
Differential Revision: https://reviews.llvm.org/D82703
This reverts commit 502a67dd7f.
This expose a failure in test-suite build on PowerPC,
revert to unblock buildbot first,
Dave will re-commit in https://reviews.llvm.org/D96287.
Thanks Dave.
This patch improves the index management during constraint building.
Previously, the code rejected constraints which used values that were not
part of Value2Index, but after combining the coefficients of the new
indices were 0 (if ShouldAdd was 0).
In those cases, no new indices need to be added. Instead of adding to
Value2Index directly, add new indices to the NewIndices map. The caller
can then check if it needs to add any new indices.
This enables checking constraints like `a + x <= a + n` to `x <= n`,
even if there is no constraint for `a` directly.
This patch updates some places where VectorLoopValueMap is accessed
directly to instead go through VPTransformState.
As we move towards managing created values exclusively in VPTransformState,
this ensures the use always can fetch the correct value.
This is in preparation for D92285, which switches to managing scalarized
values through VPValues.
In the future, the various fix* functions should be moved directly into
the VPlan codegen stage.
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D95757
As discussed in:
https://llvm.org/PR49055
We invert instcombine's add->or transform here
because it makes it easier to identify factorization
transforms like the mul in the motivating test.
This extends the logic added with:
https://reviews.llvm.org/rG70472f3https://reviews.llvm.org/rG93f3d7f
(I intentionally kept the formatting fix in this patch
to provide more context about the calling logic.)
PR49043 exposed a problem when it comes to RAUW llvm.assumes. While
D96106 would fix it for GVNSink, it seems a more general concern. To
avoid future problems this patch moves away from the vector of weak
reference model used in the assumption cache. Instead, we track the
llvm.assume calls with a callback handle which will remove itself from
the cache if the call is deleted.
Fixes PR49043.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D96168
Type tests used only by assumes were original for devirtualization, but
are meant to be kept through the first invocation of LTT so that they
can be used for additional optimization. In the regular LTO case where
the IR is analyzed we may find a resolution for the type test and end up
rewriting the associated vtable global, which can have implications on
section splitting. Simply ignore these type tests.
Fixes PR48245.
Differential Revision: https://reviews.llvm.org/D96083
Summary:
This resolves an issue posted on Bugzilla. https://bugs.llvm.org/show_bug.cgi?id=48764
In this issue, the loop had multiple exit blocks, which resulted in the
function getExitBlock to return a nullptr, which resulted in hitting the assert.
This patch ensures that loops which only have one exit block as allowed to be
unrolled and jammed.
Reviewed By: Whitney, Meinersbur, dmgreen
Differential Revision: https://reviews.llvm.org/D95806
emitting retainRV or claimRV calls in the IR
This reapplies 3fe3946d9a without the
changes made to lib/IR/AutoUpgrade.cpp, which was violating layering.
Original commit message:
Background:
This patch makes changes to the front-end and middle-end that are
needed to fix a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.
https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
What this patch does to fix the problem:
- The front-end adds operand bundle "clang.arc.rv" to calls, which
indicates the call is implicitly followed by a marker instruction and
an implicit retainRV/claimRV call that consumes the call result. In
addition, it emits a call to @llvm.objc.clang.arc.noop.use, which
consumes the call result, to prevent the middle-end passes from changing
the return type of the called function. This is currently done only when
the target is arm64 and the optimization level is higher than -O0.
- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
with the operand bundle in the IR and removes the inserted calls after
processing the function.
- ARC contract pass emits retainRV/claimRV calls after the call with the
operand bundle. It doesn't remove the operand bundle on the call since
the backend needs it to emit the marker instruction. The retainRV and
claimRV calls are emitted late in the pipeline to prevent optimization
passes from transforming the IR in a way that makes it harder for the
ARC middle-end passes to figure out the def-use relationship between
the call and the retainRV/claimRV calls (which is the cause of
PR31925).
- The function inliner removes an autoreleaseRV call in the callee if
nothing in the callee prevents it from being paired up with the
retainRV/claimRV call in the caller. It then inserts a release call if
the call is annotated with claimRV since autoreleaseRV+claimRV is
equivalent to a release. If it cannot find an autoreleaseRV call, it
tries to transfer the operand bundle to a function call in the callee.
This is important since ARC optimizer can remove the autoreleaseRV
returning the callee result, which makes it impossible to pair it up
with the retainRV/claimRV call in the caller. If that fails, it simply
emits a retain call in the IR if the implicit call is a call to
retainRV and does nothing if it's a call to claimRV.
Future work:
- Use the operand bundle on x86-64.
- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls annotated with the operand bundles.
rdar://71443534
Differential Revision: https://reviews.llvm.org/D92808
Dynamic allocas that still exist have been verified to be only used
'locally' not accross a suspend point.
rdar://73903220
Differential Revision: https://reviews.llvm.org/D96071
emitting retainRV or claimRV calls in the IR
Background:
This patch makes changes to the front-end and middle-end that are
needed to fix a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.
https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
What this patch does to fix the problem:
- The front-end adds operand bundle "clang.arc.rv" to calls, which
indicates the call is implicitly followed by a marker instruction and
an implicit retainRV/claimRV call that consumes the call result. In
addition, it emits a call to @llvm.objc.clang.arc.noop.use, which
consumes the call result, to prevent the middle-end passes from changing
the return type of the called function. This is currently done only when
the target is arm64 and the optimization level is higher than -O0.
- ARC optimizer temporarily emits retainRV/claimRV calls after the calls
with the operand bundle in the IR and removes the inserted calls after
processing the function.
- ARC contract pass emits retainRV/claimRV calls after the call with the
operand bundle. It doesn't remove the operand bundle on the call since
the backend needs it to emit the marker instruction. The retainRV and
claimRV calls are emitted late in the pipeline to prevent optimization
passes from transforming the IR in a way that makes it harder for the
ARC middle-end passes to figure out the def-use relationship between
the call and the retainRV/claimRV calls (which is the cause of
PR31925).
- The function inliner removes an autoreleaseRV call in the callee if
nothing in the callee prevents it from being paired up with the
retainRV/claimRV call in the caller. It then inserts a release call if
the call is annotated with claimRV since autoreleaseRV+claimRV is
equivalent to a release. If it cannot find an autoreleaseRV call, it
tries to transfer the operand bundle to a function call in the callee.
This is important since ARC optimizer can remove the autoreleaseRV
returning the callee result, which makes it impossible to pair it up
with the retainRV/claimRV call in the caller. If that fails, it simply
emits a retain call in the IR if the implicit call is a call to
retainRV and does nothing if it's a call to claimRV.
Future work:
- Use the operand bundle on x86-64.
- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls annotated with the operand bundles.
rdar://71443534
Differential Revision: https://reviews.llvm.org/D92808
getIntrinsicInstrCost takes a IntrinsicCostAttributes holding various
parameters of the intrinsic being costed. It can either be called with a
scalar intrinsic (RetTy==Scalar, VF==1), with a vector instruction
(RetTy==Vector, VF==1) or from the vectorizer with a scalar type and
vector width (RetTy==Scalar, VF>1). A RetTy==Vector, VF>1 is considered
an error. Both of the vector modes are expected to be treated the same,
but because this is confusing many backends end up getting it wrong.
Instead of trying work with those two values separately this removes the
VF parameter, widening the RetTy/ArgTys by VF used called from the
vectorizer. This keeps things simpler, but does require some other
modifications to keep things consistent.
Most backends look like this will be an improvement (or were not using
getIntrinsicInstrCost). AMDGPU needed the most changes to keep the code
from c230965ccf working. ARM removed the fix in
dfac521da1, webassembly happens to get a fixup for an SLP cost
issue and both X86 and AArch64 seem to now be using better costs from
the vectorizer.
Differential Revision: https://reviews.llvm.org/D95291
If we know that the scalar epilogue is required to run, modify the CFG to end the middle block with an unconditional branch to scalar preheader. This is instead of a conditional branch to either the preheader or the exit block.
The motivation to do this is to support multiple exit blocks. Specifically, the current structure forces us to identify immediate dominators and *which* exit block to branch from in the middle terminator. For the multiple exit case - where we know require scalar will hold - these questions are ill formed.
This is the last change needed to support multiple exit loops, but since the diffs are already large enough, I'm going to land this, and then enable separately. You can think of this as being NFCI-ish prep work, but the changes are a bit too involved for me to feel comfortable tagging the change that way.
Differential Revision: https://reviews.llvm.org/D94892
These attributes were all incorrect or inappropriate for LLVM to infer:
- inaccessiblememonly is generally wrong; user replacement operator new
can access memory that's visible to the caller, as can a new_handler
function.
- willreturn is generally wrong; a custom new_handler is not guaranteed
to terminate.
- noalias is inappropriate: Clang has a flag to determine whether this
attribute should be present and adds it itself when appropriate.
- noundef and nonnull on the return value should be specified by the
frontend on all 'operator new' functions if we want them, not here.
In any case, inferring attributes on functions declared 'nobuiltin' (as
these are when Clang emits them) seems questionable.
Several of the new attributes here were incorrect, and even the ones
that are generally correct were being added even to nobuiltin calls.
This reverts commit bb3f169b59.
This patch extends the condition collection logic to allow adding
conditions from pre-headers to loop headers, by allowing cases where the
target block dominates some of its predecessors.
This patch detaches SampleProfileLoader from class
SampleCoverageTracker. We plan to move SampleProfileLoader
to a template class. This would remain SampleCoverageTracker
as a class.
Also make callsiteIsHot() as a file static function.
Differential Revision: https://reviews.llvm.org/D95823
This patch updates the induction value creation to use VPValues of
recipes to map the created values. This should bring is one step closer
to being able to optimize induction recipes directly in VPlan.
Currently widenIntOrFpInduction also generates vector values for a cast
of the induction, if it exists. Make this explicit by adding the cast
instruction to the values defined by the recipe.
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D92284
This patch adds constructors to VPIteration as a cleaner way of
initialising the struct and replaces existing constructions of
the form:
{Part, Lane}
with
VPIteration(Part, Lane)
I have also added a default constructor, which is used by VPlan.cpp
when deciding whether to replicate a block or not.
This refactoring will be required in a later patch that adds more
members and functions to VPIteration.
Differential Revision: https://reviews.llvm.org/D95676
C identifier name input sections such as __llvm_prf_* are GC roots so
they cannot be discarded. In LLD, the SHF_LINK_ORDER flag overrides the
C identifier name semantics.
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object, and it
gets lowered to SHF_LINK_ORDER flag. When a function symbol is discarded
by the linker, setting up !associated metadata allows linker to discard
counters, data and values associated with that function symbol.
Note that !associated metadata is only supported by ELF, it does not have
any effect on non-ELF targets.
Differential Revision: https://reviews.llvm.org/D76802
Sample re-annotation is required in LTO time to achieve a reasonable post-inline profile quality. However, we have seen that such LTO-time re-annotation degrades profile quality. This is mainly caused by preLTO code duplication that is done by passes such as loop unrolling, jump threading, indirect call promotion etc, where samples corresponding to a source location are aggregated multiple times due to the duplicates. In this change we are introducing a concept of distribution factor for pseudo probes so that samples can be distributed for duplicated probes scaled by a factor. We hope that optimizations duplicating code well-maintain the branch frequency information (BFI) based on which probe distribution factors are calculated. Distribution factors are updated at the end of preLTO pipeline to reflect an estimated portion of the real execution count.
This change also introduces a pseudo probe verifier that can be run after each IR passes to detect duplicated pseudo probes.
A saturated distribution factor stands for 1.0. A pesudo probe will carry a factor with the value ranged from 0.0 to 1.0. A 64-bit integral distribution factor field that represents [0.0, 1.0] is associated to each block probe. Unfortunately this cannot be done for callsite probes due to the size limitation of a 32-bit Dwarf discriminator. A 7-bit distribution factor is used instead.
Changes are also needed to the sample profile inliner to deal with prorated callsite counts. Call sites duplicated by PreLTO passes, when later on inlined in LTO time, should have the callees’s probe prorated based on the Prelink-computed distribution factors. The distribution factors should also be taken into account when computing hotness for inline candidates. Also, Indirect call promotion results in multiple callisites. The original samples should be distributed across them. This is fixed by adjusting the callisites' distribution factors.
Reviewed By: wmi
Differential Revision: https://reviews.llvm.org/D93264
Inlining sometimes maps different instructions to be inlined onto the same instruction.
We must ensure to only remap the noalias scopes once. Otherwise the scope might disappear (at best).
This patch ensures that we only replace scopes for which the mapping is known.
This approach is preferred over tracking which instructions we already handled in a SmallPtrSet,
as that one will need more memory.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D95862
Refactoring SampleProfileLoader::inlineHotFunctions to use helpers from CSSPGO inlining and reduce similar code in the inlining loop, plus minor cleanup for AFDO path.
This is resubmit of D95024, with build break and overtighten assertion fixed.
Test Plan:
This is a yet another hint that we will eventually need InstCombineInverter,
which would consistently sink inversions, but but for that we'll need
to consistently hoist inversions where possible, so let's do that here.
Example of a proof: https://alive2.llvm.org/ce/z/78SbDq
See https://bugs.llvm.org/show_bug.cgi?id=48995
This patch updates IRBuilder::CreateMaskedGather/Scatter to work
with ScalableVectorType and adds isLegalMaskedGather/Scatter functions
to AArch64TargetTransformInfo. In addition I've fixed up
isLegalMaskedLoad/Store to return true for supported scalar types,
since this is what the vectorizer asks for.
In LoopVectorize.cpp I've changed
LoopVectorizationCostModel::getInterleaveGroupCost to return an invalid
cost for scalable vectors, since currently this relies upon using shuffle
vector for reversing vectors. In addition, in
LoopVectorizationCostModel::setCostBasedWideningDecision I have assumed
that the cost of scalarising memory ops is infinitely expensive.
I have added some simple masked load/store and gather/scatter tests,
including cases where we use gathers and scatters for conditional invariant
loads and stores.
Differential Revision: https://reviews.llvm.org/D95350
Refactoring SampleProfileLoader::inlineHotFunctions to use helpers from CSSPGO inlining and reduce similar code in the inlining loop, plus minor cleanup for AFDO path.
Test Plan:
Differential Revision: https://reviews.llvm.org/D95024
This change implemented call site prioritized BFS profile guided inlining for sample profile loader. The new inlining strategy maximize the benefit of context-sensitive profile as mentioned in the follow up discussion of CSSPGO RFC. The change will not affect today's AutoFDO as it's opt-in. CSSPGO now defaults to the new FDO inliner, but can fall back to today's replay inliner using a switch (`-sample-profile-prioritized-inline=0`).
Motivation
With baseline AutoFDO, the inliner in sample profile loader only replays previous inlining, and the use of profile is only for pruning previous inlining that turned out to be cold. Due to the nature of replay, the FDO inliner is simple with hotness being the only decision factor. It has the following limitations that we're improving now for CSSPGO.
- It doesn't take inline candidate size into account. Since it's doing replay, the size growth is bounded by previous CGSCC inlining. With context-sensitive profile, FDO inliner is no longer limited by previous inlining, so we need to take size into account to avoid significant size bloat.
- The way it looks at hotness is not accurate. It uses total samples in an inlinee as proxy for hotness, while what really matters for an inline decision is the call site count. This is an unfortunate fall back because call site count and callee entry count are not reliable due to dwarf based correlation, especially for inlinees. Now paired with pseudo-probe, we have accurate call site count and callee's entry count, so we can use that to gauge hotness more accurately.
- It treats all call sites from a block as hot as long as there's one call site considered hot. This is normally true, but since total samples is used as hotness proxy, this transitiveness within block magnifies the inacurate hotness heuristic. With pseduo-probe and the change above, this is no longer an issue for CSSPGO.
New FDO Inliner
Putting all the requirement for CSSPGO together, we need a top-down call site prioritized BFS inliner. Here're reasons why each component is needed.
- Top-down: We need a top-down inliner to better leverage context-sensitive profile, so inlining is driven by accurate context profile, and post-inline is also accurate. This is already implemented in https://reviews.llvm.org/D70655.
- Size Cap: For top-down inliner, taking function size into account for inline decision alone isn't sufficient to control size growth. We also need to explicitly cap size growth because with top-down inlining, we can grow inliner size significantly with large number of smaller inlinees even if each individually passes the cost/size check.
- Prioritize call sites: With size cap, inlining order also becomes important, because if we stop inlining due to size budget limit, we'd want to use budget towards the most beneficial call sites.
- BFS inline: Same as call site prioritization, if we stop inlining due to size budget limit, we want a balanced inline tree, rather than going deep on one call path.
Note that the new inliner avoids repeatedly evaluating same set of call site, so it should help with compile time too. For this reason, we could transition today's FDO inliner to use a queue with equal priority to avoid wasted reevaluation of same call site (TODO).
Speculative indirect call promotion and inlining is also supported now with CSSPGO just like baseline AutoFDO.
Tunings and knobs
I created tuning knobs for size growth/cap control, and for hot threshold separate from CGSCC inliner. The default values are selected based on initial tuning with CSSPGO.
Results
Evaluated with an internal LLVM fork couple months ago, plus another change to adjust hot-threshold cutoff for context profile (will send up after this one), the new inliner show ~1% geomean perf win on spec2006 with CSSPGO, while reducing code size too. The measurement was done using train-train setup, MonoLTO w/ new pass manager and pseudo-probe. Note that this is just a starting point - we hope that the new inliner will open up more opportunity with CSSPGO, but it will certainly take more time and effort to make it fully calibrated and ready for bigger workloads (we're working on it).
Differential Revision: https://reviews.llvm.org/D94001
Extend applyLoopGuards() to take into account conditions/assumes proving some
value %v to be divisible by D by rewriting %v to (%v / D) * D. This lets the
loop unroller and the loop vectorizer identify more loops as not requiring
remainder loops.
Differential Revision: https://reviews.llvm.org/D95521
C identifier name input sections such as __llvm_prf_* are GC roots so
they cannot be discarded. In LLD, the SHF_LINK_ORDER flag overrides the
C identifier name semantics.
The !associated metadata may be attached to a global object declaration
with a single argument that references another global object, and it
gets lowered to SHF_LINK_ORDER flag. When a function symbol is discarded
by the linker, setting up !associated metadata allows linker to discard
counters, data and values associated with that function symbol.
Note that !associated metadata is only supported by ELF, it does not have
any effect on non-ELF targets.
Differential Revision: https://reviews.llvm.org/D76802
Fixing up a couple places where `getCallSiteIdentifier` is needed to support pseudo-probe-based callsites.
Also fixing an issue in the extbinary profile reader where the metadata section is not fully scanned based on the number of profiles loaded only for the current module.
Reviewed By: wmi, wenlei
Differential Revision: https://reviews.llvm.org/D95791
This is another step (see D95452) towards correcting fast-math-flags
bugs in vector reductions.
There are multiple bugs visible in the test diffs, and this is still
not working as it should. We still use function attributes (rather
than FMF) to drive part of the logic, but we are not checking for
the correct FP function attributes.
Note that FMF may not be propagated optimally on selects (example
in https://llvm.org/PR35607 ). That's why I'm proposing to union the
FMF of a fcmp+select pair and avoid regressions on existing vectorizer
tests.
Differential Revision: https://reviews.llvm.org/D95690
A == B map to A >= B && A <= B
(https://alive2.llvm.org/ce/z/_dwxKn).
This extends the constraint construction to return a list of
constraints, which can be used to properly de-compose nested AND & OR.
If the incoming block to a phi node is an EH pad, then we will
materialize into an EH pad, which is not supposed to happen. To fix
this, I added a check to see if incoming block of a phi node is an EH
pad before using it as the insertion point.
Differential Revision: https://reviews.llvm.org/D95019
The constant trunc/ext may not be the optimal pre-condition,
but I think that handles the common cases.
Example of Alive2 proof:
https://alive2.llvm.org/ce/z/sREeLC
This is another step towards canonicalizing to the intrinsics.
Narrowing was identified as source of potential regression for
abs(), so we need to handle this for min/max - see:
https://llvm.org/PR48816
If this is not enough, we could process intrinsics in
the trunc-driven matching in canEvaluateTruncated().
Instead of using ConstraintSystem::negate when adding new constraints,
flip the condition in IR.
The main advantage is that EQ predicates can be represented by 2
constraints, which makes negating based on the constraint tricky. The IR
condition can easily negated.
D90687 introduced a crash:
llvm::LoopVectorizationCostModel::computeMaxVF(llvm::ElementCount, unsigned int):
Assertion `WideningDecisions.empty() && Uniforms.empty() && Scalars.empty() &&
"No decisions should have been taken at this point"' failed.
when compiling the following C code:
typedef struct {
char a;
} b;
b *c;
int d, e;
int f() {
int g = 0;
for (; d; d++) {
e = 0;
for (; e < c[d].a; e++)
g++;
}
return g;
}
with:
clang -Os -target hexagon -mhvx -fvectorize -mv67 testcase.c -S -o -
This occurred since prior to D90687 computeFeasibleMaxVF would only be
called in computeMaxVF when a scalar epilogue was allowed, but now it's
always called. This causes the assert above since computeFeasibleMaxVF
collects all viable VFs larger than the default MaxVF, and for each VF
calculates the register usage which results in analysis being done the
assert above guards against. This can occur in computeFeasibleMaxVF if
TTI.shouldMaximizeVectorBandwidth and this target hook is implemented in
the hexagon backend to always return true.
Reported by @iajbar.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D94869
If we determine that the invariant path through the loop has no effects,
we can directly branch to the exit block, instead to unswitching first.
Besides avoiding some extra work (unswitching first, then deleting the
loop again) this allows to be more aggressive than regular unswitching
with respect to cost-modeling. This approach should always be be
desirable.
This is similar in spirit to D93734, just that it uses the previously
added checks for loop-unswitching.
I tried to add the required no-op checks from scratch, as we only check
a subset of the loop. There is potential to unify the checks with
LoopDeletion, at the cost of adding a predicate whether a block should
be considered.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D95468
The reduction of a sanitizer build failure when enabling the dominance check (D95335) showed that loop peeling also needs to take care of scope duplication, just like loop unrolling (D92887).
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D95544
This patch fixes updating MemorySSA if the header contains memory
defs that do not clobber a duplicated instruction. We need to find the
first defining access outside the loop body and use that as defining
access of the duplicated instruction.
This fixes a crash caused by bee486851c.
This patch emits "instr_prof_hash_mismatch" function annotation metadata if
there is a hash mismatch while applying instrumented profiles.
During the PGO optimized build using instrumented profiles, if the CFG of
the function has changed since generating the profile, a hash mismatch is
encountered. This patch emits this information as annotation metadata. We
plan to use this with Propeller which is done at the machine IR level.
Propeller is usually applied on top of PGO and a hash mismatch during
PGO could be used to detect source drift.
Differential Revision: https://reviews.llvm.org/D95495
splitCodeGen does not need to take ownership of the module, as it
currently clones the original module for each split operation.
There is an ~4 year old fixme to change that, but until this is
addressed, the function can just take a reference to the module.
This makes the transition of LTOCodeGenerator to use LTOBackend a bit
easier, because under some circumstances, LTOCodeGenerator needs to
write the original module back after codegen.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D95222
GCC warning:
```
/llvm-project/llvm/lib/Transforms/Scalar/ScalarizeMaskedMemIntrin.cpp: In function ‘void scalarizeMaskedStore(llvm::CallInst*, llvm::DomTreeUpdater*, bool&)’:
/llvm-project/llvm/lib/Transforms/Scalar/ScalarizeMaskedMemIntrin.cpp:295:15: warning: variable ‘IfBlock’ set but not used [-Wunused-but-set-variable]
295 | BasicBlock *IfBlock = CI->getParent();
| ^~~~~~~
/llvm-project/llvm/lib/Transforms/Scalar/ScalarizeMaskedMemIntrin.cpp: In function ‘void scalarizeMaskedScatter(llvm::CallInst*, llvm::DomTreeUpdater*, bool&)’:
/llvm-project/llvm/lib/Transforms/Scalar/ScalarizeMaskedMemIntrin.cpp:555:15: warning: variable ‘IfBlock’ set but not used [-Wunused-but-set-variable]
555 | BasicBlock *IfBlock = CI->getParent();
| ^~~~~~~
```
This de-pessimizes the arguably more usual case of no masked mem intrinsics,
and gets rid of one more Dominator Tree recalculation.
As per llvm/test/CodeGen/X86/opt-pipeline.ll,
there's one more Dominator Tree recalculation left, we could get rid of.
and fix a few edge cases that show up in the Swift compiler but
weren't caught by the existing tests. Most notably the old code wasn't
salvaging load operations correctly. The patch also gets rid of the
LoadFromFramePtr argument and replaces it with a more generalized
mechanism.
SimplifyCFG is an utility pass, and the fact that it does not
preserve DomTree's, forces it's users to somehow workaround that,
likely by not preserving DomTrees's themselves.
Indeed, simplifycfg pass didn't know how to preserve dominator tree,
it took me just under a month (starting with e113317958)
do rectify that, now it fully knows how to,
there's likely some problems with that still,
but i've dealt with everything i can spot so far.
I think we now can flip the switch.
Note that this is functionally an NFC change,
since this doesn't change the users to pass in the DomTree,
that is a separate question.
Reviewed By: kuhar, nikic
Differential Revision: https://reviews.llvm.org/D94827
This change brings up support of context-sensitive profiles in the format of extended binary. Existing sample profile reader/writer/merger code is being tweaked to reflect the fact of bracketed input contexts, like (`[...]`). The paired brackets are also needed in extbinary profiles because we don't yet have an otherwise good way to tell calling contexts apart from regular function names since the context delimiter `@` can somehow serve as a part of the C++ mangled names.
Reviewed By: wmi, wenlei
Differential Revision: https://reviews.llvm.org/D95547
Identify dynamically exported symbols (--export-dynamic[-symbol=],
--dynamic-list=, or definitions needed to preempt shared objects) and
prevent their LTO visibility from being upgraded.
This helps avoid use of whole program devirtualization when there may
be overrides in dynamic libraries.
Differential Revision: https://reviews.llvm.org/D91583
I am trying to untangle the fast-math-flags propagation logic
in the vectorizers (see a6f022127 for SLP).
The loop vectorizer has a mix of checking FP function attributes,
IR-level FMF, and just wrong assumptions.
I am trying to avoid regressions while fixing this, and I think
the IR-level logic is good enough for that, but it's hard to say
for sure. This would be the 1st step in the clean-up.
The existing test that I changed to include 'fast' actually shows
a miscompile: the function only had the equivalent of nnan, but we
created new instructions that had fast (all FMF set). This is
similar to the example in https://llvm.org/PR35538
Differential Revision: https://reviews.llvm.org/D95452
Imported functions and variable get the visibility from the module supplying the
definition. However, non-imported definitions do not get the visibility from
(ELF) the most constraining visibility among all modules (Mach-O) the visibility
of the prevailing definition.
This patch
* adds visibility bits to GlobalValueSummary::GVFlags
* computes the result visibility and propagates it to all definitions
Protected/hidden can imply dso_local which can enable some optimizations (this
is stronger than GVFlags::DSOLocal because the implied dso_local can be
leveraged for ELF -shared while default visibility dso_local has to be cleared
for ELF -shared).
Note: we don't have summaries for declarations, so for ELF if a declaration has
the most constraining visibility, the result visibility may not be that one.
Differential Revision: https://reviews.llvm.org/D92900
This gives the user control over which expander to use, which in turn
allows the user to decide what to do with the expanded instructions.
Used in D75980.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D94295
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.
Differential Revision: https://reviews.llvm.org/D94820
This patch improves the availability for variables stored in the
coroutine frame by emitting an alloca to hold the pointer to the frame
object and rewriting dbg.declare intrinsics to point inside the frame
object using salvaged DIExpressions. Finally, a new alloca is created
in the funclet to hold the FramePtr pointer to ensure that it is
available throughout the entire function at -O0.
This path also effectively reverts D90772. The testcase updates
highlight nicely how every removed CHECK for a dbg.value is preceded
by a new CHECK for a dbg.declare.
Thanks to JunMa, Yifeng, and Bruno for their thoughtful reviews!
Differential Revision: https://reviews.llvm.org/D93497
rdar://71866936
As it looks like NewPM generally is using SimpleLoopUnswitch
instead of LoopUnswitch, this patch also use SimpleLoopUnswitch
in the ExtraVectorizerPasses sequence (compared with LegacyPM
which use the LoopUnswitch pass).
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D95457
This change implements support for applying profile instrumentation
only to selected files or functions. The implementation uses the
sanitizer special case list format to select which files and functions
to instrument, and relies on the new noprofile IR attribute to exclude
functions from instrumentation.
Differential Revision: https://reviews.llvm.org/D94820
The switch must set the predicate correctly; anything else
should lead to unreachable/assert.
I'm trying to fix FMF propagation here and the callers,
so this is a preliminary cleanup.
This patch adds additional checks to avoid partial unswitching
in cases where it won't be profitable, e.g. because the path directly
exits the loop anyways.
Loop peeling removes conditions from loop bodies that become invariant
after a small number of iterations. When triggered, this leads to fewer
compares and possibly PHIs in loop bodies, enabling further
optimizations. The current cost-model of loop peeling should be quite
conservative/safe, i.e. only peel if a condition in the loop becomes
known after peeling.
For example, see PR47671, where loop peeling enables vectorization by
removing a PHI the vectorizer does not understand. Granted, the
loop-vectorizer could also be taught about constant PHIs, but loop
peeling is likely to enable other optimizations as well.
This has an impact on quite a few benchmarks from
MultiSource/SPEC2000/SPEC2006 on X86 with -O3 -flto, for example
Same hash: 186 (filtered out)
Remaining: 51
Metric: loop-vectorize.LoopsVectorized
Program base patch diff
test-suite...ve-susan/automotive-susan.test 8.00 9.00 12.5%
test-suite...nal/skidmarks10/skidmarks.test 35.00 31.00 -11.4%
test-suite...lications/sqlite3/sqlite3.test 41.00 43.00 4.9%
test-suite...s/ASC_Sequoia/AMGmk/AMGmk.test 25.00 26.00 4.0%
test-suite...006/450.soplex/450.soplex.test 88.00 89.00 1.1%
test-suite...TimberWolfMC/timberwolfmc.test 120.00 119.00 -0.8%
test-suite.../CINT2006/403.gcc/403.gcc.test 215.00 216.00 0.5%
test-suite...006/447.dealII/447.dealII.test 957.00 958.00 0.1%
test-suite...ternal/HMMER/hmmcalibrate.test 75.00 75.00 0.0%
Same hash: 186 (filtered out)
Remaining: 51
Metric: loop-vectorize.LoopsAnalyzed
Program base patch diff
test-suite...ks/Prolangs-C/agrep/agrep.test 440.00 434.00 -1.4%
test-suite...nal/skidmarks10/skidmarks.test 312.00 308.00 -1.3%
test-suite...marks/7zip/7zip-benchmark.test 6399.00 6323.00 -1.2%
test-suite...lications/minisat/minisat.test 134.00 135.00 0.7%
test-suite...rks/FreeBench/pifft/pifft.test 295.00 297.00 0.7%
test-suite...TimberWolfMC/timberwolfmc.test 1879.00 1869.00 -0.5%
test-suite...pplications/treecc/treecc.test 689.00 691.00 0.3%
test-suite...T2000/300.twolf/300.twolf.test 1593.00 1597.00 0.3%
test-suite.../Benchmarks/Bullet/bullet.test 1394.00 1392.00 -0.1%
test-suite...ications/JM/ldecod/ldecod.test 1431.00 1429.00 -0.1%
test-suite...6/464.h264ref/464.h264ref.test 2229.00 2230.00 0.0%
test-suite...lications/sqlite3/sqlite3.test 2590.00 2589.00 -0.0%
test-suite...ications/JM/lencod/lencod.test 2732.00 2733.00 0.0%
test-suite...006/453.povray/453.povray.test 3395.00 3394.00 -0.0%
Note the -11% regression in number of loops vectorized for skidmarks. I
suspect this corresponds to the fact that those loops are gone now (see
the reduction in number of loops analyzed by LV).
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D88471
This patch fixes llvm-link crash when materializing global variable
with appending linkage and initializer that depends on another
global with appending linkage.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D95329
This change leverages the work done in D83743 to replay in the SampleProfile inliner to also be used in the CGSCC inliner. NOTE: currently restricted to non-ML advisors only.
The added switch `-cgscc-inline-replay=<remarks file>` will replay the inlining decisions in that file where the remarks file is generated via `-Rpass=inline`. The aim here is to make it easier to analyze changes that would modify inlining heuristics to be separated from this behavior. Doing so allows easier examination of assembly and runtime behavior compared to the baseline rather than trying to dig through the large churn caused by inlining.
In LTO compilation, since inlining is done twice you can separately specify replay by passing the flag to the FE (`-cgscc-inline-replay=`) and to the linker (`-Wl,cgscc-inline-replay=`) with the remarks generated from their respective places.
Testing on mysqld by comparing the inline decisions between base (generates remarks.txt) and diff (replay using identical input/tools with remarks.txt) and examining the inlining sites with `diff` shows 14,000 mismatches out of 247,341 for a ~94% replay accuracy. I believe this gap can be narrowed further though for the general case we may never achieve full accuracy. For my personal use, this is close enough to be representative: I set the baseline as the one generated by the replay on identical input/toolset and compare that to my modified input/toolset using the same replay.
Testing:
ninja check-llvm
newly added test correctly replays CGSCC inlining decisions
Reviewed By: mtrofin, wenlei
Differential Revision: https://reviews.llvm.org/D94334
When LSR converts a branch on the pre-inc IV into a branch on the
post-inc IV, the nowrap flags on the addition may no longer be valid.
Previously, a poison result of the addition might have been ignored,
in which case the program was well defined. After branching on the
post-inc IV, we might be branching on poison, which is undefined behavior.
Fix this by discarding nowrap flags which are not present on the SCEV
expression. Nowrap flags on the SCEV expression are proven by SCEV
to always hold, independently of how the expression will be used.
This is essentially the same fix we applied to IndVars LFTR, which
also performs this kind of pre-inc to post-inc conversion.
I believe a similar problem can also exist for getelementptr inbounds,
but I was not able to come up with a problematic test case. The
inbounds case would have to be addressed in a differently anyway
(as SCEV does not track this property).
Fixes https://bugs.llvm.org/show_bug.cgi?id=46943.
Differential Revision: https://reviews.llvm.org/D95286
or claimRV calls in the IR
Background:
This patch makes changes to the front-end and middle-end that are
needed to fix a longstanding problem where llvm breaks ARC's autorelease
optimization (see the link below) by separating calls from the marker
instructions or retainRV/claimRV calls. The backend changes are in
https://reviews.llvm.org/D92569.
https://clang.llvm.org/docs/AutomaticReferenceCounting.html#arc-runtime-objc-autoreleasereturnvalue
What this patch does to fix the problem:
- The front-end annotates calls with attribute "clang.arc.rv"="retain"
or "clang.arc.rv"="claim", which indicates the call is implicitly
followed by a marker instruction and a retainRV/claimRV call that
consumes the call result. This is currently done only when the target
is arm64 and the optimization level is higher than -O0.
- ARC optimizer temporarily emits retainRV/claimRV calls after the
annotated calls in the IR and removes the inserted calls after
processing the function.
- ARC contract pass emits retainRV/claimRV calls after the annotated
calls. It doesn't remove the attribute on the call since the backend
needs it to emit the marker instruction. The retainRV/claimRV calls
are emitted late in the pipeline to prevent optimization passes from
transforming the IR in a way that makes it harder for the ARC
middle-end passes to figure out the def-use relationship between the
call and the retainRV/claimRV calls (which is the cause of PR31925).
- The function inliner removes the autoreleaseRV call in the callee that
returns the result if nothing in the callee prevents it from being
paired up with the calls annotated with "clang.arc.rv"="retain/claim"
in the caller. If the call is annotated with "claim", a release call
is inserted since autoreleaseRV+claimRV is equivalent to a release. If
it cannot find an autoreleaseRV call, it tries to transfer the
attributes to a function call in the callee. This is important since
ARC optimizer can remove the autoreleaseRV call returning the callee
result, which makes it impossible to pair it up with the retainRV or
claimRV call in the caller. If that fails, it simply emits a retain
call in the IR if the call is annotated with "retain" and does nothing
if it's annotated with "claim".
- This patch teaches dead argument elimination pass not to change the
return type of a function if any of the calls to the function are
annotated with attribute "clang.arc.rv". This is necessary since the
pass can incorrectly determine nothing in the IR uses the function
return, which can happen since the front-end no longer explicitly
emits retainRV/claimRV calls in the IR, and change its return type to
'void'.
Future work:
- Use the attribute on x86-64.
- Fix the auto upgrader to convert call+retainRV/claimRV pairs into
calls annotated with the attributes.
rdar://71443534
Differential Revision: https://reviews.llvm.org/D92808
Now that VPRecipeBase inherits from VPDef, we can always use the new
VPValue for replacement, if the recipe defines one. Given the recipes
that are supported at the moment, all new recipes must have either 0 or
1 defined values.
Fixes an infinite loop encountered in GVN.
GVN will delay PRE if it encounters critical edges, attempt to split
them later via calls to SplitCriticalEdge(), then restart.
The caller of GVN::splitCriticalEdges() assumed a return value of true
meant that critical edges were split, that the IR had changed, and that
PRE should be re-attempted, upon which we loop infinitely.
This was exposed after D88438, by compiling the Linux kernel for s390,
but the test case is reproducible on x86.
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1261
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D94996
turning off SampleFDO silently.
Currently sample loader pass turns off SampleFDO optimization silently when
it sees error in reading the profile. This behavior will defeat the tests
which could have caught those bad/incompatible profile problems. This patch
change the behavior to report error.
Differential Revision: https://reviews.llvm.org/D95269
We can sink extends after min/max if they match and would
not change the sign-interpreted compare. The only combo
that doesn't work is zext+smin/smax because the zexts
could change a negative number into positive:
https://alive2.llvm.org/ce/z/D6sz6J
Sext+umax/umin works:
define i32 @src(i8 %x, i8 %y) {
%0:
%sx = sext i8 %x to i32
%sy = sext i8 %y to i32
%m = umax i32 %sx, %sy
ret i32 %m
}
=>
define i32 @tgt(i8 %x, i8 %y) {
%0:
%m = umax i8 %x, %y
%r = sext i8 %m to i32
ret i32 %r
}
Transformation seems to be correct!
In the cloning infrastructure, only track an MDNode mapping,
without explicitly storing the Metadata mapping, same as is done
during inlining. This makes things slightly simpler.
a6f0221276 enabled intersection of FMF on reduction instructions,
so it is safe to ease the check here.
There is still some room to improve here - it looks like we
have nearly duplicate flags propagation logic inside of the
LoopUtils helper but it is limited targets that do not form
reduction intrinsics (they form the shuffle expansion).
A @llvm.experimental.noalias.scope.decl is only useful if there is !alias.scope and !noalias metadata that uses the declared scope.
When that is not the case for at least one of the two, the intrinsic call can as well be removed.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D95141
Similar to D92887, LoopRotation also needs duplicate the noalias scopes when rotating a `@llvm.experimental.noalias.scope.decl` across a block boundary.
This is based on the version from the Full Restrict paches (D68511).
The problem it fixes also showed up in Transforms/Coroutines/ex5.ll after D93040 (when enabling strict checking with -verify-noalias-scope-decl-dom).
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D94306
This is a fix for https://bugs.llvm.org/show_bug.cgi?id=39282. Compared to D90104, this version is based on part of the full restrict patched (D68484) and uses the `@llvm.experimental.noalias.scope.decl` intrinsic to track the location where !noalias and !alias.scope scopes have been introduced. This allows us to only duplicate the scopes that are really needed.
Notes:
- it also includes changes and tests from D90104
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D92887
Add an intrinsic type class to represent the
llvm.experimental.noalias.scope.decl intrinsic, to make code
working with it a bit nicer by hiding the metadata extraction
from view.
Some utilities used by InstCombine, like SimplifyLibCalls, may add new
instructions and replace the uses of a call, but return nullptr because
the inserted call produces multiple results.
Previously, the replaced library calls would get removed by
InstCombine's deleter, but after
292077072e this may not happen, if the
willreturn attribute is missing.
As a work-around, update replaceInstUsesWith to set MadeIRChange, if it
replaces any uses. This catches the cases where it is used as replacer
by utilities used by InstCombine and seems useful in general; updating
uses will modify the IR.
This fixes an expensive-check failure when replacing
@__sinpif/@__cospifi with @__sincospif_sret.
As shown in the test diffs, we could miscompile by
propagating flags that did not exist in the original
code.
The flags required for fmin/fmax reductions will be
fixed in a follow-up patch.
With the addition of the `willreturn` attribute, functions that may
not return (e.g. due to an infinite loop) are well defined, if they are
not marked as `willreturn`.
This patch updates `wouldInstructionBeTriviallyDead` to not consider
calls that may not return as dead.
This patch still provides an escape hatch for intrinsics, which are
still assumed as willreturn unconditionally. It will be removed once
all intrinsics definitions have been reviewed and updated.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D94106
If i change it to AssertingVH instead, a number of existing tests fail,
which means we don't consistently remove from the set when deleting blocks,
which means newly-created blocks may happen to appear in that set
if they happen to occupy the same memory chunk as did some block
that was in the set originally.
There are many places where we delete blocks,
and while we could probably consistently delete from LoopHeaders
when deleting a block in transforms located in SimplifyCFG.cpp itself,
transforms located elsewhere (Local.cpp/BasicBlockUtils.cpp) also may
delete blocks, and it doesn't seem good to teach them to deal with it.
Since we at most only ever delete from LoopHeaders,
let's just delegate to WeakVH to do that automatically.
But to be honest, personally, i'm not sure that the idea
behind LoopHeaders is sound.
Insert a llvm.experimental.noalias.scope.decl intrinsic that identifies where a noalias argument was inlined.
This patch includes some refactorings from D90104.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D93040
This builds on the restricted after initial revert form of D93906, and adds back support for breaking backedges of inner loops. It turns out the original invalidation logic wasn't quite right, specifically around the handling of LCSSA.
When breaking the backedge of an inner loop, we can cause blocks which were in the outer loop only because they were also included in a sub-loop to be removed from both loops. This results in the exit block set for our original parent loop changing, and thus a need for new LCSSA phi nodes.
This case happens when the inner loop has an exit block which is also an exit block of the parent, and there's a block in the child which reaches an exit to said block without also reaching an exit to the parent loop.
(I'm describing this in terms of the immediate parent, but the problem is general for any transitive parent in the nest.)
The approach implemented here involves a potentially expensive LCSSA rebuild. Perf testing during review didn't show anything concerning, but we may end up needing to revert this if anyone encounters a practical compile time issue.
Differential Revision: https://reviews.llvm.org/D94378
Similar to binary operators like fadd/fmul/fsub, propagate shape info
through unary operators (fneg is the only one?).
Differential Revision: https://reviews.llvm.org/D95252
I have previously tried doing that in
b33fbbaa34 / d38205144f,
but eventually it was pointed out that the approach taken there
was just broken wrt how the uses of bonus instructions are updated
to account for the fact that they should now use either bonus instruction
or the cloned bonus instruction. In particluar, all that manual handling
of PHI nodes in successors was just wrong.
But, the fix is actually much much simpler than my initial approach:
just tell SSAUpdate about both instances of bonus instruction,
and let it deal with all the PHI handling.
Alive2 confirms that the reproducers from the original bugs (@pr48450*)
are now handled correctly.
This effectively reverts commit 59560e8589,
effectively relanding b33fbbaa34.
NewBonusInst just took name from BonusInst, so BonusInst has no name,
so BonusInst.getName() makes no sense.
So we need to ask NewBonusInst for the name.
This is to support the memory routines vec_malloc, vec_calloc, vec_realloc, and vec_free. These routines manage memory that is 16-byte aligned. And they are only available on AIX.
Differential Revision: https://reviews.llvm.org/D94710
If the call result is unused, we should let it get DCEd rather
than replacing it. Also, don't try to replace an existing sincos
with another one (unless it's as part of combining sin and cos).
This avoids an infinite combine loop if the calls are not DCEd
as expected, which can happen with D94106 and lack of willreturn
annotation in hand-crafted IR.
In the motivating cases from https://llvm.org/PR48816 ,
we have a trailing trunc. But that is not required to
reduce the abs width:
https://alive2.llvm.org/ce/z/ECaz-p
...as long as we clear the int-min-is-poison bit (nsw).
We have some existing tests that are affected, and I'm
not sure what the overall implications are, but in general
we favor narrowing operations over preserving nsw/nuw.
If that causes problems, we could restrict this transform
based on type (shouldChangeType() and/or vector vs. scalar).
Differential Revision: https://reviews.llvm.org/D95235
The existing code did not deal with atomic loads correctly. Such loads
are represented as MemoryDefs. Bail out on any MemoryAccess that is not
a MemoryUse.
Because we were not looking for the llvm.coro.id.async intrinsic in the
early coro pass which triggers follow-up passes we relied on the
llvm.coro.end intrinsic being present. This might not be the case in
functions that end in unreachable code.
Differential Revision: https://reviews.llvm.org/D95144
Iff we know we can get rid of the inversions in the new pattern,
we can thus get rid of the inversion in the old pattern,
this decreasing instruction count.
Note that we could position this transformation as just hoisting
of the `not` (still, iff y is freely negatible), but the test changes
show a number of regressions, so let's not do that.
Iff we know we can get rid of the inversions in the new pattern,
we can thus get rid of the inversion in the old pattern,
this decreasing instruction count.
I'm intentionally structuring it this way, so that the actual fold only
does the fold, and no legality/correctness checks, all of which must be
done by the caller. This allows for the fold code to be more compact
and more easily grokable.
Hoist the successor updating out of the code that deals with branch
weight updating, and hoist the 'has weights' check from the latter,
making code more consistent and easier to follow.
While we already ignore uncond branches, we could still potentially
end up with a conditional branches with identical destinations
due to the visitation order, or because we were called as an utility.
But if we have such a disguised uncond branch,
we still probably shouldn't deal with it here.
The case where BB ends with an unconditional branch,
and has a single predecessor w/ conditional branch
to BB and a single successor of BB is exactly the pattern
SpeculativelyExecuteBB() transform deals with.
(and in this case they both allow speculating only a single instruction)
Well, or FoldTwoEntryPHINode(), if the final block
has only those two predecessors.
Here, in FoldBranchToCommonDest(), only a weird subset of that
transform is supported, and it's glued on the side in a weird way.
In particular, it took me a bit to understand that the Cond
isn't actually a branch condition in that case, but just the value
we allow to speculate (otherwise it reads as a miscompile to me).
Additionally, this only supports for the speculated instruction
to be an ICmp.
So let's just unclutter FoldBranchToCommonDest(), and leave
this transform up to SpeculativelyExecuteBB(). As far as i can tell,
this shouldn't really impact optimization potential, but if it does,
improving SpeculativelyExecuteBB() will be more beneficial anyways.
Notably, this only affects a single test,
but EarlyCSE should have run beforehand in the pipeline,
and then FoldTwoEntryPHINode() would have caught it.
This reverts commit rL158392 / commit d33f4efbfd.
Walking the use list of a Constant (particularly, ConstantData)
is not scalable, since a given constant may be used by many
instructinos in many functions in many modules.
Differential Revision: https://reviews.llvm.org/D94713
I have removed an unnecessary assert in LoopVectorizationCostModel::getInstructionCost
that prevented a cost being calculated for select instructions when using
scalable vectors. In addition, I have changed AArch64TTIImpl::getCmpSelInstrCost
to only do special cost calculations for fixed width vectors and fall
back to the base version for scalable vectors.
I have added a simple cost model test for cmps and selects:
test/Analysis/CostModel/sve-cmpsel.ll
and some simple tests that show we vectorize loops with cmp and select:
test/Transforms/LoopVectorize/AArch64/sve-basic-vec.ll
Differential Revision: https://reviews.llvm.org/D95039
This adds cost modelling for the inloop vectorization added in
745bf6cf44. Up until now they have been modelled as the original
underlying instruction, usually an add. This happens to works OK for MVE
with instructions that are reducing into the same type as they are
working on. But MVE's instructions can perform the equivalent of an
extended MLA as a single instruction:
%sa = sext <16 x i8> A to <16 x i32>
%sb = sext <16 x i8> B to <16 x i32>
%m = mul <16 x i32> %sa, %sb
%r = vecreduce.add(%m)
->
R = VMLADAV A, B
There are other instructions for performing add reductions of
v4i32/v8i16/v16i8 into i32 (VADDV), for doing the same with v4i32->i64
(VADDLV) and for performing a v4i32/v8i16 MLA into an i64 (VMLALDAV).
The i64 are particularly interesting as there are no native i64 add/mul
instructions, leading to the i64 add and mul naturally getting very
high costs.
Also worth mentioning, under NEON there is the concept of a sdot/udot
instruction which performs a partial reduction from a v16i8 to a v4i32.
They extend and mul/sum the first four elements from the inputs into the
first element of the output, repeating for each of the four output
lanes. They could possibly be represented in the same way as above in
llvm, so long as a vecreduce.add could perform a partial reduction. The
vectorizer would then produce a combination of in and outer loop
reductions to efficiently use the sdot and udot instructions. Although
this patch does not do that yet, it does suggest that separating the
input reduction type from the produced result type is a useful concept
to model. It also shows that a MLA reduction as a single instruction is
fairly common.
This patch attempt to improve the costmodelling of in-loop reductions
by:
- Adding some pattern matching in the loop vectorizer cost model to
match extended reduction patterns that are optionally extended and/or
MLA patterns. This marks the cost of the reduction instruction correctly
and the sext/zext/mul leading up to it as free, which is otherwise
difficult to tell and may get a very high cost. (In the long run this
can hopefully be replaced by vplan producing a single node and costing
it correctly, but that is not yet something that vplan can do).
- getExtendedAddReductionCost is added to query the cost of these
extended reduction patterns.
- Expanded the ARM costs to account for these expanded sizes, which is a
fairly simple change in itself.
- Some minor alterations to allow inloop reduction larger than the highest
vector width and i64 MVE reductions.
- An extra InLoopReductionImmediateChains map was added to the vectorizer
for it to efficiently detect which instructions are reductions in the
cost model.
- The tests have some updates to show what I believe is optimal
vectorization and where we are now.
Put together this can greatly improve performance for reduction loop
under MVE.
Differential Revision: https://reviews.llvm.org/D93476
In LoopInterchange, `findInnerReductionPhi()` looks for reduction
variables, which cannot be constants. Update it to return early in that
case.
This also addresses a blocker for removing use-lists from ConstantData,
whose users could be spread across arbitrary modules in the same
LLVMContext.
Differential Revision: https://reviews.llvm.org/D94712
This is NFC-intended and removes the "OperationData"
class which had become nothing more than a recurrence
(reduction) type.
I adjusted the matching logic to distinguish
instructions from non-instructions - that's all that
the "IsLeafValue" member was keeping track of.
If a function doesn't contain loops and does not call non-willreturn
functions, then it is willreturn. Loops are detected by checking
for backedges in the function. We don't attempt to handle finite
loops at this point.
Differential Revision: https://reviews.llvm.org/D94633
In https://llvm.org/PR48810 , we are crashing while trying to
propagate attributes from mempcpy (returns void*) to memcpy
(returns nothing - void).
We can avoid the crash by removing known incompatible
attributes for the void return type.
I'm not sure if this goes far enough (should we just drop all
attributes since this isn't the same function?). We also need
to audit other transforms in LibCallSimplifier to make sure
there are no other cases that have the same problem.
Differential Revision: https://reviews.llvm.org/D95088
This patch applies the idea from D93734 to LoopUnswitch.
It adds support for unswitching on conditions that are only
invariant along certain paths through a loop.
In particular, it targets conditions in the loop header that
depend on values loaded from memory. If either path from
the true or false successor through the loop does not modify
memory, perform partial loop unswitching.
That is, duplicate the instructions feeding the condition in the pre-header.
Then unswitch on the duplicated condition. The condition is now known
in the unswitched version for the 'invariant' path through the original loop.
On caveat of this approach is that one of the loops created can be partially
unswitched again. To avoid this behavior, `llvm.loop.unswitch.partial.disable`
metadata is added to the unswitched loops, to avoid subsequent partial
unswitching.
If that's the approach to go, I can move the code handling the metadata kind
into separate functions.
This increases the cases we unswitch quite a bit in SPEC2006/SPEC2000 &
MultiSource. It also allows us to eliminate a dead loop in SPEC2017's omnetpp
```
Tests: 236
Same hash: 170 (filtered out)
Remaining: 66
Metric: loop-unswitch.NumBranches
Program base patch diff
test-suite...000/255.vortex/255.vortex.test 2.00 23.00 1050.0%
test-suite...T2006/401.bzip2/401.bzip2.test 7.00 55.00 685.7%
test-suite :: External/Nurbs/nurbs.test 5.00 26.00 420.0%
test-suite...s-C/unix-smail/unix-smail.test 1.00 3.00 200.0%
test-suite.../Prolangs-C++/ocean/ocean.test 1.00 3.00 200.0%
test-suite...tions/lambda-0.1.3/lambda.test 1.00 3.00 200.0%
test-suite...yApps-C++/PENNANT/PENNANT.test 2.00 5.00 150.0%
test-suite...marks/Ptrdist/yacr2/yacr2.test 1.00 2.00 100.0%
test-suite...lications/viterbi/viterbi.test 1.00 2.00 100.0%
test-suite...plications/d/make_dparser.test 12.00 24.00 100.0%
test-suite...CFP2006/433.milc/433.milc.test 14.00 27.00 92.9%
test-suite.../Applications/lemon/lemon.test 7.00 12.00 71.4%
test-suite...ce/Applications/Burg/burg.test 6.00 10.00 66.7%
test-suite...T2006/473.astar/473.astar.test 16.00 26.00 62.5%
test-suite...marks/7zip/7zip-benchmark.test 78.00 121.00 55.1%
```
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D93764
This reverts commit d97f776be5.
The original problem was due to build failures in shared lib builds. D95079
moved ImportedFunctionsInliningStatistics under Analysis, unblocking
this.
This is related to D94982. We want to call these APIs from the Analysis
component, so we can't leave them under Transforms.
Differential Revision: https://reviews.llvm.org/D95079
Branch/assume conditions in PredicateInfo are currently handled in
a rather ad-hoc manner, with some arbitrary limitations. For example,
an `and` of two `icmp`s will be handled, but an `and` of an `icmp`
and some other condition will not. That also includes the case where
more than two conditions and and'ed together.
This patch makes the handling more general by looking through and/ors
up to a limit and considering all kinds of conditions (though operands
will only be taken for cmps of course).
Differential Revision: https://reviews.llvm.org/D94447
When using 2 InlinePass instances in the same CGSCC - one for other
mandatory inlinings, the other for the heuristic-driven ones - the order
in which the ImportedFunctionStats would be output-ed would depend on
the destruction order of the inline passes, which is not deterministic.
This patch moves the ImportedFunctionStats responsibility to the
InlineAdvisor to address this problem.
Differential Revision: https://reviews.llvm.org/D94982
We were able to remove almost all of the state from
OperationData, so these don't make sense as members
of that class - just pass the RecurKind in as a param.
More streamlining is possible, but I'm trying to avoid
logic/typo bugs while fixing this. Eventually, we should
not need the `OperationData` class.
We were able to remove almost all of the state from
OperationData, so these don't make sense as members
of that class - just pass the RecurKind in as a param.
Loop peeling assumes that the loop's latch is a conditional branch. Add
a check to canPeel that explicitly checks for this, and testcases that
otherwise fail an assertion when trying to peel a loop whose back-edge
is a switch case or the non-unwind edge of an invoke.
Reviewed By: skatkov, fhahn
Differential Revision: https://reviews.llvm.org/D94995
Summary: This is to address bug48712.
The solution in this patch is that when we want to merge two variable a
into the storage frame of variable b only if the alignment of a is
multiple of b.
There may be other strategies. But now I think they are hard to handle
and benefit little. Or we can implement them in the future.
Test-plan: check-llvm
Reviewers: jmorse, lxfind, junparser
Differential Revision: https://reviews.llvm.org/D94891
Currently LLVM is relying on ValueTracking's `isKnownNonZero` to attach `nonnull`, which can return true when the value is poison.
To make the semantics of `nonnull` consistent with the behavior of `isKnownNonZero`, this makes the semantics of `nonnull` to accept poison, and return poison if the input pointer isn't null.
This makes many transformations like below legal:
```
%p = gep inbounds %x, 1 ; % p is non-null pointer or poison
call void @f(%p) ; instcombine converts this to call void @f(nonnull %p)
```
Instead, this semantics makes propagation of `nonnull` to caller illegal.
The reason is that, passing poison to `nonnull` does not immediately raise UB anymore, so such program is still well defined, if the callee does not use the argument.
Having `noundef` attribute there re-allows this.
```
define void @f(i8* %p) { ; functionattr cannot mark %p nonnull here anymore
call void @g(i8* nonnull %p) ; .. because @g never raises UB if it never uses %p.
ret void
}
```
Another attribute that needs to be updated is `align`. This patch updates the semantics of align to accept poison as well.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D90529
separate sections.
For ThinLTO, all the function profiles without context has been annotated to
outline functions if possible in prelink phase. In postlink phase, profile
annotation in postlink phase is only meaningful for function profile with
context. If the profile is large, it is better to split the profile into two
parts, one with context and one without, so the profile reading in postlink
phase only has to read the part with context. To have the profile splitting,
we extend the ExtBinary format to support different section arrangement. It
will be flexible to add other section layout in the future without the need
to create new class inheriting from ExtBinary class.
Differential Revision: https://reviews.llvm.org/D94435
The pass has dependency on 'TargetTransformInfoWrapperPass', but the
corresponding call to INITIALIZE_PASS_DEPENDENCY was missing.
Differential Revision: https://reviews.llvm.org/D94916
Relative to the original change, this adds a check that the
instruction on which we're replacing operands is safe to speculatively
execute, because that's what we're effectively doing. We're executing
the instruction with the replaced operand, which is fine if it's pure,
but not fine if can cause side-effects or UB (aka is not speculatable).
Additionally, we cannot (generally) replace operands in phi nodes,
as these may refer to a different loop iteration. This is also covered
by the speculation check.
-----
InstCombine already performs a fold where X == Y ? f(X) : Z is
transformed to X == Y ? f(Y) : Z if f(Y) simplifies. However,
if f(X) only has one use, then we can always directly replace the
use inside the instruction. To actually be profitable, limit it to
the case where Y is a non-expr constant.
This could be further extended to replace uses further up a one-use
instruction chain, but for now this only looks one level up.
Among other things, this also subsumes D94860.
Differential Revision: https://reviews.llvm.org/D94862
Just like llvm.assume, there are a lot of cases where we can just ignore llvm.experimental.noalias.scope.decl.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D93042
This caused a miscompile in Chromium, see comments on the codereview for
discussion and pointer to a reproducer.
> InstCombine already performs a fold where X == Y ? f(X) : Z is
> transformed to X == Y ? f(Y) : Z if f(Y) simplifies. However,
> if f(X) only has one use, then we can always directly replace the
> use inside the instruction. To actually be profitable, limit it to
> the case where Y is a non-expr constant.
>
> This could be further extended to replace uses further up a one-use
> instruction chain, but for now this only looks one level up.
>
> Among other things, this also subsumes D94860.
>
> Differential Revision: https://reviews.llvm.org/D94862
This also reverts the follow-up
a003f26539cf4db744655e76c41f4c4a8913f116:
> [llvm] Prevent infinite loop in InstCombine of select statements
>
> This fixes an issue where the RHS and LHS the comparison operation
> creating the predicate were swapped back and forth forever.
>
> Differential Revision: https://reviews.llvm.org/D94934
D84108 exposed a bad interaction between inlining and loop-rotation
during regular LTO, which is causing notable regressions in at least
CINT2006/473.astar.
The problem boils down to: we now rotate a loop just before the vectorizer
which requires duplicating a function call in the preheader when compiling
the individual files ('prepare for LTO'). But this then prevents further
inlining of the function during LTO.
This patch tries to resolve this issue by making LoopRotate more
conservative with respect to rotating loops that have inline-able calls
during the 'prepare for LTO' stage.
I think this change intuitively improves the current situation in
general. Loop-rotate tries hard to avoid creating headers that are 'too
big'. At the moment, it assumes all inlining already happened and the
cost of duplicating a call is equal to just doing the call. But with LTO,
inlining also happens during full LTO and it is possible that a previously
duplicated call is actually a huge function which gets inlined
during LTO.
From the perspective of LV, not much should change overall. Most loops
calling user-provided functions won't get vectorized to start with
(unless we can infer that the function does not touch memory, has no
other side effects). If we do not inline the 'inline-able' call during
the LTO stage, we merely delayed loop-rotation & vectorization. If we
inline during LTO, chances should be very high that the inlined code is
itself vectorizable or the user call was not vectorizable to start with.
There could of course be scenarios where we inline a sufficiently large
function with code not profitable to vectorize, which would have be
vectorized earlier (by scalarzing the call). But even in that case,
there probably is no big performance impact, because it should be mostly
down to the cost-model to reject vectorization in that case. And then
the version with scalarized calls should also not be beneficial. In a way,
LV should have strictly more information after inlining and make more
accurate decisions (barring cost-model issues).
There is of course plenty of room for things to go wrong unexpectedly,
so we need to keep a close look at actual performance and address any
follow-up issues.
I took a look at the impact on statistics for
MultiSource/SPEC2000/SPEC2006. There are a few benchmarks with fewer
loops rotated, but no change to the number of loops vectorized.
Reviewed By: sanwou01
Differential Revision: https://reviews.llvm.org/D94232
This fixes an issue where the RHS and LHS the comparison operation
creating the predicate were swapped back and forth forever.
Differential Revision: https://reviews.llvm.org/D94934
A previous patch has already changed getInstructionCost to return
an InstructionCost type. This patch changes the other various
getXXXCost functions to return an InstructionCost too. This is a
non-functional change - I've added a few asserts that the costs
are valid in places where we're selecting between vector call
and intrinsic costs. However, since we don't yet return invalid
costs from any of the TTI implementations these asserts should
not fire.
See this patch for the introduction of the type: https://reviews.llvm.org/D91174
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2020-November/146408.html
Differential Revision: https://reviews.llvm.org/D94065
This patch teaches SimplifyCFG::SimplifyBranchOnICmpChain to understand select form of
(x == C1 || x == C2 || ...) / (x != C1 && x != C2 && ...) and optimize them into switch if possible.
D93065 has more context about the transition, including links to the list of optimizations being updated.
Differential Revision: https://reviews.llvm.org/D93943
After much refactoring over the last 2 weeks to the reduction
matching code, I think this change is finally ready.
We effectively broke fmax/fmin vector reduction optimization
when we started canonicalizing to intrinsics in instcombine,
so this should restore that functionality for SLP.
There are still FMF problems here as noted in the code comments,
but we should be avoiding miscompiles on those for fmax/fmin by
restricting to full 'fast' ops (negative tests are included).
Fixing FMF propagation is a planned follow-up.
Differential Revision: https://reviews.llvm.org/D94913
This patch adds the default value of 1 to drop_begin.
In the llvm codebase, 70% of calls to drop_begin have 1 as the second
argument. The interface similar to with std::next should improve
readability.
This patch converts a couple of calls to drop_begin as examples.
Differential Revision: https://reviews.llvm.org/D94858
This is to address https://bugs.llvm.org/show_bug.cgi?id=48626.
When there are musttail calls that use parameters aliasing the newly created coroutine frame, the existing implementation will fatal.
We simply cannot perform CoroElide in such cases. In theory a precise analysis can be done to check whether the parameters of the musttail call
actually alias the frame, but it's very hard to do it before the transformation happens. Also in most cases the existence of musttail call is
generated due to symmetric transfers, and in those cases alias analysis won't be able to tell that they don't alias anyway.
Differential Revision: https://reviews.llvm.org/D94834
This will avoid confusion once we start matching
min/max intrinsics. All of these hacks to accomodate
cmp+sel idioms should disappear once we canonicalize
to min/max intrinsics.
The icmp opcode is now hard-coded in the cost model call.
This will make it easier to eventually remove all opcode
queries for min/max patterns as we transition to intrinsics.
This patch marks some library functions as willreturn. On the first pass, I
excluded most functions that interact with streams/the filesystem.
Along with willreturn, it also adds nounwind to a set of math functions.
There probably are a few additional attributes we can add for those, but
that should be done separately.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D94684
This patch changes these functions:
vectorizeLoadInsert
isExtractExtractCheap
foldExtractedCmps
scalarizeBinopOrCmp
getShuffleExtract
foldBitcastShuf
to use the class InstructionCost when calling TTI.get<something>Cost().
This patch is part of a series of patches to use InstructionCost instead of
unsigned/int for the cost model functions.
See this thread for context:
http://lists.llvm.org/pipermail/llvm-dev/2020-November/146408.html
See this patch for the introduction of the type:
https://reviews.llvm.org/D91174
ps.:This patch adds the test || !NewCost.isValid(), because we want to
return false when:
!NewCost.isValid && !OldCost.isValid()->the cost to transform it expensive
and
!NewCost.isValid() && OldCost.isValid()
Therefore for simplication we only add test for !NewCost.isValid()
Differential Revision: https://reviews.llvm.org/D94069
InstCombine already performs a fold where X == Y ? f(X) : Z is
transformed to X == Y ? f(Y) : Z if f(Y) simplifies. However,
if f(X) only has one use, then we can always directly replace the
use inside the instruction. To actually be profitable, limit it to
the case where Y is a non-expr constant.
This could be further extended to replace uses further up a one-use
instruction chain, but for now this only looks one level up.
Among other things, this also subsumes D94860.
Differential Revision: https://reviews.llvm.org/D94862
When removing catchpad's from catchswitch, if that removes a successor,
we need to record that in DomTreeUpdater.
This fixes PostDomTree preservation failure in an existing test.
This appears to be the single issue that i see in my current test coverage.
This is NFC-intended and another step towards supporting
intrinsics as reduction candidates.
The remaining bits of the OperationData class do not make
much sense as-is, so I will try to improve that, but I'm
trying to take minimal steps because it's still not clear
how this was intended to work.
This is another NFC-intended patch to allow matching
intrinsics (example: maxnum) as candidates for reductions.
It's possible that the loop/if logic can be reduced now,
but it's still difficult to understand how this all works.
Expanding from D94808 - we ensure the same InlineAdvisor is used by both
InlinerPass instances. The notion of mandatory inlining is moved into
the core InlineAdvisor: advisors anyway have to handle that case, so
this change also factors out that a bit better.
Differential Revision: https://reviews.llvm.org/D94825
To get into this block we had: !A || B || C
and we checked C in the first 'if' clause
leaving !A || B. But the 2nd 'if' is checking:
A && !B --> !(!A || B)
DestBB might or might not already be a successor of SelectBB,
and it wasn't we need to ensure that we record the fact in DomTree.
The testcase used to crash in lazy domtree updater mode + non-per-function
domtree validity checks disabled.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
This is not nice, but it's the best transient solution possible,
and is better than just duplicating the whole function.
The problem is, this function is widely used,
and it is not at all obvious that all the users
could be painlessly switched to operate on DomTreeUpdater,
and somehow i don't feel like porting all those users first.
This function is one of last three that not operate on DomTreeUpdater.
Even though not all it's users operate on DomTreeUpdater,
it itself internally operates on DomTreeUpdater,
so it must mean everything is fine with that,
so just do that globally.
Summary:
Set the default for the option enabling memory ssa use in the loop sink
pass to true for the new pass manager.
Author: Jamie Schmeiser <schmeise@ca.ibm.com>
Reviewed By: asbirlea (Alina Sbirlea)
Differential Revision: https://reviews.llvm.org/D92486
Juneyoung Lee