We wanted to check if all uses of the function are direct calls, but the
code didn't account for passing the function as a parameter.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D128104
llvm.used and llvm.compiler.used are often used with inline assembly
that refers to a specific symbol so that the symbol is kept through to
the linker even though there are no references to it from LLVM IR.
This fixes the MergeFunctions pass to preserve references to these
symbols in llvm.used/llvm.compiler.used so they are not deleted from the
IR. This doesn't prevent these functions from being merged, but
guarantees that an alias or thunk with the expected symbol name is kept
in the IR.
Differential Revision: https://reviews.llvm.org/D127751
Previously if the inliner split an SCC such that an empty one remained, the MLInlineAdvisor could potentially lose track of the EdgeCount if a subsequent CGSCC pass modified the calls of a function that was initially in the SCC pre-split. Saving the seen nodes in onPassEntry resolves this.
Reviewed By: mtrofin
Differential Revision: https://reviews.llvm.org/D127693
Adding the `DW_CC_nocall` calling convention to the function debug metadata is needed when either the return values or the arguments of a function are removed as this helps in informing debugger that it may not be safe to call this function or try to interpret the return value.
This translates to setting `DW_AT_calling_convention` with `DW_CC_nocall` for appropriate DWARF DIEs.
The DWARF5 spec (section 3.3.1.1 Calling Convention Information) says:
If the `DW_AT_calling_convention` attribute is not present, or its value is the constant `DW_CC_normal`, then the subroutine may be safely called by obeying the `standard` calling conventions of the target architecture. If the value of the calling convention attribute is the constant `DW_CC_nocall`, the subroutine does not obey standard calling conventions, and it may not be safe for the debugger to call this subroutine.
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D127134
Adds option to print the contents of the Inline Advisor after each SCC Inliner pass
Reviewed By: mtrofin
Differential Revision: https://reviews.llvm.org/D127689
This patch improves the fix in D110529 to prevent from crashing on value
with byval attribute that is not added in SCCP solver.
Authored-by: sinan.lin@linux.alibaba.com
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D126355
Per the documentation in Support/InstructionCost.h, the purpose of an invalid cost is so that clients can change behavior on impossible to cost inputs. CodeMetrics was instead asserting that invalid costs never occurred.
On a target with an incomplete cost model - e.g. RISCV - this means that transformations would crash on (falsely) invalid constructs - e.g. scalable vectors. While we certainly should improve the cost model - and I plan to do so in the near future - we also shouldn't be crashing. This violates the explicitly stated purpose of an invalid InstructionCost.
I updated all of the "easy" consumers where bailouts were locally obvious. I plan to follow up with loop unroll in a following change.
Differential Revision: https://reviews.llvm.org/D127131
For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.
This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.
`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.
We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good.
Fixes: https://github.com/llvm/llvm-project/issues/54981
When determining liveness via Attributor::isAssumedDead(...) we might
end up without a liveness AA or with one pointing into another function.
Neither is helpful and we will avoid both from now on.
Clang-format InstructionSimplify and convert all "FunctionName"s to
"functionName". This patch does touch a lot of files but gets done with
the cleanup of InstructionSimplify in one commit.
This is the alternative to the less invasive clang-format only patch: D126783
Reviewed By: spatel, rengolin
Differential Revision: https://reviews.llvm.org/D126889
We can use constant to allow undef and there is no need to force
integers in the API anyway. The user can decide if a non integer
constant is fine or not.
We need to be careful replacing values as call site arguments
(IRPosition::IRP_CALL_SITE_ARGUMENT) is representing a use and not a
value. This patch replaces the interface to take a IR position instead
making it harder to misuse accidentally. It does not change our tests
right now but a follow up exposed the potential footgun.
We used to be very conservative when integer states were merged.
Instead of adding the known range (which is large due to uncertainty)
into the assumed range (which is hopefully small), we can also only
allow to merge in both at the same time into their respective
counterpart. This will ensure we keep the invariant that assumed is part
of known.
When we recreate instructions as part of simplification we need to take
care of debug metadata and replacing the value multiple times. For now,
we handle both conservatively.
Some cl::ZeroOrMore were added to avoid the `may only occur zero or one times!`
error. More were added due to cargo cult. Since the error has been removed,
cl::ZeroOrMore is unneeded.
Also remove cl::init(false) while touching the lines.
This patch introduces the abstract base class InlinePriority to serve as
the comparison function for the priority queue. A derived class, such
as SizePriority, may choose to cache the priorities for different
functions for performance reasons.
This design shields the type used for the priority away from classes
outside InlinePriority and classes derived from it. In turn,
PriorityInlineOrder no longer needs to be a template class.
Reviewed By: kazu
Differential Revision: https://reviews.llvm.org/D126300
This patch introduces the abstract base class InlinePriority to serve as
the comparison function for the priority queue. A derived class, such
as SizePriority, may choose to cache the priorities for different
functions for performance reasons.
This design shields the type used for the priority away from classes
outside InlinePriority and classes derived from it. In turn,
PriorityInlineOrder no longer needs to be a template class.
Reviewed By: kazu
Differential Revision: https://reviews.llvm.org/D126300
There are a few places where we use report_fatal_error when the input is broken.
Currently, this function always crashes LLVM with an abort signal, which
then triggers the backtrace printing code.
I think this is excessive, as wrong input shouldn't give a link to
LLVM's github issue URL and tell users to file a bug report.
We shouldn't print a stack trace either.
This patch changes report_fatal_error so it uses exit() rather than
abort() when its argument GenCrashDiag=false.
Reviewed by: nikic, MaskRay, RKSimon
Differential Revision: https://reviews.llvm.org/D126550
This patch adds !nosanitize metadata to FixedMetadataKinds.def, !nosanitize indicates that LLVM should not insert any sanitizer instrumentation.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D126294
All callers pass true.
select-unfold-freeze.ll is now a subset of select.ll so delete it.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D126501
It doesn't matter which value we use for dead args, so let's switch
to poison, so we can eventually kill undef.
Reviewed By: aeubanks, fhahn
Differential Revision: https://reviews.llvm.org/D125983
The re-apply includes fixes to clang tests that were missed in
the original commit.
Original message:
Prior to this patch we would only set to undef the unused arguments of the
external functions. The rationale was that unused arguments of internal
functions wouldn't need to be turned into undef arguments because they
should have been simply eliminated by the time we reach that code.
This is actually not true because there are plenty of cases where we can't
remove unused arguments. For instance, if the internal function is used in
an indirect call, it may not be possible to change the function signature.
Yet, for statically known call-sites we would still like to mark the unused
arguments as undef.
This patch enables the "set undef arguments" optimization on internal
functions when we encounter cases where internal functions cannot be
optimized. I.e., whenever an internal function is marked "live".
Differential Revision: https://reviews.llvm.org/D124699
It makes sense to make a non-byval promotion attempt first and then
fall back to the byval one. The non-byval ('usual') promotion is
generally better, for example it does promotion even when a structure
has more elements than 'MaxElements' but not all of them are actually
used in the function.
Differential Revision: https://reviews.llvm.org/D124514
When a PHINode has an incoming block from outside the region, it must be handled specially when assigning a global value number to each incoming value. A PHINode has multiple predecessors, and we must handle this case rather than only the single predecessor case.
Reviewer: paquette
Differential Revision: https://reviews.llvm.org/D124777
As a follow-up to D124632, I'm turning on unlimited size caps for inlining with preinlined profile. It should be safe as a preinlined profile has "bounded" inline contexts.
No noticeable size or perf delta was seen with two of our internal large services, but I think this is still a good change to be consistent with the other case.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D124793
The two fields have the same meaning. Their values come from the reader. Therefore I'm removing one.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D124788
Prior to this patch we would only set to undef the unused arguments of the
external functions. The rationale was that unused arguments of internal
functions wouldn't need to be turned into undef arguments because they
should have been simply eliminated by the time we reach that code.
This is actually not true because there are plenty of cases where we can't
remove unused arguments. For instance, if the internal function is used in
an indirect call, it may not be possible to change the function signature.
Yet, for statically known call-sites we would still like to mark the unused
arguments as undef.
This patch enables the "set undef arguments" optimization on internal
functions when we encounter cases where internal functions cannot be
optimized. I.e., whenever an internal function is marked "live".
Differential Revision: https://reviews.llvm.org/D124699
libcalls." (was 0f8c626). This reverts commit 14d9390.
The patch previously failed to recognize cases where user had defined a
function alias with an identical name as that of the library
function. Module::getFunction() would then return nullptr which is what the
sanitizer discovered.
In this updated version a new function isLibFuncEmittable() has as well been
introduced which is now used instead of TLI->has() anytime a library function
is to be emitted . It additionally also makes sure there is e.g. no function
alias with the same name in the module.
Reviewed By: Eli Friedman
Differential Revision: https://reviews.llvm.org/D123198
If there are pre-existing dead instructions, the order we visit replaced
values can cause us sometimes to not delete dead instructions.
The added test non-deterministically failed without the change.
X86 codegen uses function attribute `min-legal-vector-width` to select the proper ABI. The intention of the attribute is to reflect user's requirement when they passing or returning vector arguments. So Clang front-end will iterate the vector arguments and set `min-legal-vector-width` to the width of the maximum for both caller and callee.
It is assumed any middle end optimizations won't care of the attribute expect inlining and argument promotion.
- For inlining, we will propagate the attribute of inlined functions because the inlining functions become the newer caller.
- For argument promotion, we check the `min-legal-vector-width` of the caller and callee and refuse to promote when they don't match.
The problem comes from the optimizations' combination, as shown by https://godbolt.org/z/zo3hba8xW. The caller `foo` has two callees `bar` and `baz`. When doing argument promotion, both `foo` and `bar` has the same `min-legal-vector-width`. So the argument was promoted to vector. Then the inlining inlines `baz` to `foo` and updates `min-legal-vector-width`, which results in ABI mismatch between `foo` and `bar`.
This patch fixes the problem by expanding the concept of `min-legal-vector-width` to indicator of functions arguments. That says, any passes touch functions arguments have to set `min-legal-vector-width` to the value reflects the width of vector arguments. It makes sense to me because any arguments modifications are ABI related and should response for the ABI compatibility.
Differential Revision: https://reviews.llvm.org/D123284
We have seen that the prioirty inliner delivered on-par performance with the old inliner for probe-only CSSPGO profile, as long as without a size budget. I'm turning on the priority inliner for probe-only profile by default.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D124632
To be more clear and definitive, I'm renaming `ProfileIsCSFlat` back to `ProfileIsCS` which stands for full context-sensitive flat profiles. `ProfileIsCSNested` is now renamed to `ProfileIsPreInlined` and is extended to be applicable for CS flat profiles too. More specifically, `ProfileIsPreInlined` is for any kind of profiles (flat or nested) that contain 'ShouldBeInlined' contexts. The flag is encoded in the profile summary section for extbinary profiles and is computed on-the-fly for text profiles.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D122602
The legacy LoopUnswitch pass is only used in the legacy pass manager
pipeline, which is deprecated.
The NewPM replacement is SimpleLoopUnswitch and I think it is time to
remove the legacy LoopUnswitch code.
Fixes#31000.
Reviewed By: aeubanks, Meinersbur, asbirlea
Differential Revision: https://reviews.llvm.org/D124376
The structure ArgPart and alias OffsetAndArgPart have been moved
into the anonymous namespace. NFC.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D124617
The condition should be 'ArgParts.size() > MaxElements', so that if we
have exactly 3 elements in the 'ArgParts' vector, the promotion should
be allowed because the 'MaxElement' threshold is not exceeded yet.
The default value for 'MaxElement' has been decreased to 2 in order
to avoid an actual change in argument promoting behavior. However,
this changes byval argument transformation behavior by allowing
adding not more than 2 arguments to the function instead of 3 allowed
before.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D124178
Some loop counters ('i', 'e') and variables ('type') were named not
in accordance with the code style and clang-tidy issues warnings
about the using of such variables. This patch renames the variables
and fixes some typos in the comments within the source file.
Differential Revision: https://reviews.llvm.org/D123662
The callback is expected to create a branch to the ContinuationBB (sometimes called FiniBB in some lambdas) argument when finishing. This creates problems:
1. The InsertPoint used for CodeGenIP does not need to be the end of a block. If it is not, a naive callback will insert a branch instruction into the middle of the block.
2. The BasicBlock the CodeGenIP is pointing to may or may not have a terminator. There is an conflict where to branch to if the block already has a terminator.
3. Some API functions work only with block having a terminator. Some workarounds have been used to insert a temporary terminator that is removed again.
4. Some callbacks are sensitive to whether the BasicBlock has a terminator or not. This creates a callback ordering problem where different callback may have different behaviour depending on whether a previous callback created a terminator or not. The problem also exists for FinalizeCallbackTy where some callbacks do create branch to another "continue" block, but unlike BodyGenCallbackTy does not receive the target as argument. This is not addressed in this patch.
With this patch, the callback receives an CodeGenIP into a BasicBlock where to insert instructions. If it has to insert control flow, it can split the block at that position as needed but otherwise no separate ContinuationBB is needed. In particular, a callback can be empty without breaking the emitted IR. If the caller needs the control flow to branch to a specific target, it can insert the branch instruction itself and pass an InsertPoint before the terminator to the callback.
Certain frontends such as Clang may expect the current IRBuilder position to be at the end of a basic block. In this case its callbacks must split the block at CodeGenIP before setting the IRBuilder position such that the instructions after CodeGenIP are moved to another basic block and before returning create a new branch instruction to the split block.
Some utility functions such as `splitBB` are supporting correct splitting of BasicBlocks, independent of whether they have a terminator or not, returning/setting the InsertPoint of an IRBuilder to the end of split predecessor block, and optionally omitting creating a branch to the split successor block to be added later.
Reviewed By: kiranchandramohan
Differential Revision: https://reviews.llvm.org/D118409
Since the size of most of SCC's is 1, the PriorityInlineOrder would not change the inline
order in SCC inliner.
Reviewed By: kazu
Differential Revision: https://reviews.llvm.org/D123608
MisExpect diagnostics should not prevent compilation from succeeding, and the
assertion is insufficient to prevent division by zero in release builds.
This patch addresses that by replacing the assert with an early return.
Additionally, it disables MisExpect diagnostics when using sample profiling,
since this is the only known case where this error has manifested.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D124302
test/Transforms/InstCombine/pr39177.ll failed in a -DLLVM_USE_SANITIZER=Undefined build.
```
lib/Transforms/Utils/BuildLibCalls.cpp:1217:17: runtime error: reference binding to null pointer of type 'llvm::Function'
```
`Function &F = *M->getFunction(Name);`
This reverts commit 0f8c626723.
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
A new set of overloaded functions named getOrInsertLibFunc() are now supposed
to be used instead of getOrInsertFunction() when building a libcall from
within an LLVM optimizer(). The idea is that this new function also makes
sure that any mandatory argument attributes are added to the function
prototype (after calling getOrInsertFunction()).
inferLibFuncAttributes() is renamed to inferNonMandatoryLibFuncAttrs() as it
only adds attributes that are not necessary for correctness but merely
helping with later optimizations.
Generally, the front end is responsible for building a correct function
prototype with the needed argument attributes. If the middle end however is
the one creating the call, e.g. when replacing one libcall with another, it
then must take this responsibility.
This continues the work of properly handling argument extension if required
by the target ABI when building a lib call. getOrInsertLibFunc() now does
this for all libcalls currently built by any LLVM optimizer. It is expected
that when in the future a new optimization builds a new libcall with an
integer argument it is to be added to getOrInsertLibFunc() with the proper
handling. Note that not all targets have it in their ABI to sign/zero extend
integer arguments to the full register width, but this will be done
selectively as determined by getExtAttrForI32Param().
Review: Eli Friedman, Nikita Popov, Dávid Bolvanský
Differential Revision: https://reviews.llvm.org/D123198
This reverts commit af0285122f.
The test "libomp::loop_dispatch.c" on builder
openmp-gcc-x86_64-linux-debian fails from time-to-time.
See #54969. This patch is unrelated.
The OMPScheduleType enum stores the constants from libomp's internal sched_type in kmp.h and are used by several kmp API functions. The enum values have an internal structure, namely each scheduling algorithm (e.g.) exists in four variants: unordered, orderend, normerge unordered, and nomerge ordered.
This patch (basically a followup to D114940) splits the "ordered" and "nomerge" bits into separate flags, as was already done for the "monotonic" and "nonmonotonic", so we can apply bit flags operations on them. It also now contains all possible combinations according to kmp's sched_type. Deriving of the OMPScheduleType enum from clause parameters has been moved form MLIR's OpenMPToLLVMIRTranslation.cpp to OpenMPIRBuilder to make available for clang as well. Since the primary purpose of the flag is the binary interface to libomp, it has been made more private to LLVMFrontend. The primary interface for generating worksharing-loop using OpenMPIRBuilder code becomes `applyWorkshareLoop` which derives the OMPScheduleType automatically and calls the appropriate emitter function.
While this is mostly a NFC refactor, it still applies the following functional changes:
* The logic from OpenMPToLLVMIRTranslation to derive the OMPScheduleType also applies to clang. Most notably, it now applies the nonmonotonic flag for non-static schedules by default.
* In OpenMPToLLVMIRTranslation, the nonmonotonic default flag was previously not applied if the simd modifier was used. I assume this was a bug, since the effect was due to `loop.schedule_modifier()` returning `mlir::omp::ScheduleModifier::none` instead of `llvm::Optional::None`.
* In OpenMPToLLVMIRTranslation, the nonmonotonic default flag was set even if ordered was specified, in breach to what the comment before citing the OpenMP specification says. I assume this was an oversight.
The ordered flag with parameter was not considered in this patch. Changes will need to be made (e.g. adding/modifying function parameters) when support for it is added. The lengthy names of the enum values can be discussed, for the moment this is avoiding reusing previously existing enum value names such as `StaticChunked` to avoid confusion.
Reviewed By: peixin
Differential Revision: https://reviews.llvm.org/D123403
Using the legacy PM for the optimization pipeline was deprecated in 13.0.0.
Following recent changes to remove non-core features of the legacy
PM/optimization pipeline, remove the (Thin)LTO pipelines.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D123882
This patch renames the mergefunc-sanity to mergefunc-verify and renames the related functions to use more
inclusive language
Reviewed By: cebowleratibm
Differential Revision: https://reviews.llvm.org/D114374
When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the module slice but we should not
update those AAs. We make an exception for are call site of the SCC as
they are helpful providing information for the SCC.
Minor modifications to pointer privatization allow us to perform it even
in the CGSCC pass, similar to ArgumentPromotion.
Issue: https://github.com/llvm/llvm-project/issues/54430
For incoming values of phi nodes added to an outlined function to accommodate different exit paths in the function, when a value is a constant that is passed into the outlined function as an argument, we find the corresponding value in the first extracted function used to fill the overall outlined function. When this value is an argument, the corresponding value used will be the old value, prior to outlining. This patch maintains a mapping from these values to arguments, and uses this mapping to update the added phi node accordingly.
Reviewers: paquette
Recommit of d6eb480afb
Differential Revision: https://reviews.llvm.org/D122206
Instead of lengthy constructors we can now set the members of a
read-only struct before the Attributor is created. Should make it
clearer what is configurable and also help introducing new options in
the future. This actually added IsModulePass and avoids deduction
through the Function set size. No functional change was intended.
Legacy PM for optimization pipeline was deprecated in 13.0.0 and Clang dropped
legacy PM support in D123609. This change removes legacy PM passes for PGO so
that downstream projects won't be able to use it. It seems appropriate to start
removing such "add-on" features like instrumentations, before we remove more
stuff after 15.x is branched.
I have checked many LLVM users and only ldc[1] uses the legacy PGO pass.
[1]: https://github.com/ldc-developers/ldc/issues/3961
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D123834
Issue: https://github.com/llvm/llvm-project/issues/54430
For incoming values of phi nodes added to an outlined function to accommodate different exit paths in the function, when a value is a constant that is passed into the outlined function as an argument, we find the corresponding value in the first extracted function used to fill the overall outlined function. When this value is an argument, the corresponding value used will be the old value, prior to outlining. This patch maintains a mapping from these values to arguments, and uses this mapping to update the added phi node accordingly.
Reviewers: paquette
Differential Revision: https://reviews.llvm.org/D122206
Issue: https://github.com/llvm/llvm-project/issues/54431
PHINodes that need to be generated to accommodate a PHINode outside the region due to different output paths need to have their own numbering to determine the number of output schemes required to properly handle all the outlined regions. This numbering was previously only determined by the order and values of the incoming values, as well as the parent block of the PHINode. This adds the incoming blocks to the calculation of a hash value for these PHINodes as well, and the supporting infrastructure to give each block in a region a corresponding canonical numbering.
Reviewer: paquette
Differential Revision: https://reviews.llvm.org/D122207
The Attributor, as many other parts in LLVM, uses pointer equivalence
for `llvm::Value`s. This only works as long as `llvm::Value`s are
dynamically unique, or, to be exact, we will never end up with the same
`llvm::Value` representing two dynamic instances. We already provided a
helper to check the former, namely `AA::isDynamicallyUnique`, however we
could not check the latter. In this patch we move the logic into a
separate AA which helps with the growing complexity and use cases. We
also extend the interface to answer the second question rather than the
first. So we do not determine dynamically uniqueness but if we might end
up with the `llvm::Value` describing a different dynamic instance. Note
that the latter is very much tied to the Attributor capabilities to look
through memory, recursion, etc. so we need to update the logic as we go.
We look through loads in the "generic value traversal" and we
consequently don't need to look through them again in AAValueSimplify*.
The test changes stem from the fact that we allowed any simplified
value, incl. non-dynamically unique ones, as long as the underlying
memory was an alloca. This doesn't seem to make sense as allocas do not
protect against dynamically non-unique values. We need to make the
unique check better rather than excluding allocas. That in mind, we can
remove a lot of code by simply relying on the generic value traversal
load look through.
To soften the blow some minor adjustments have been made that allow more
simplification through the now used scheme and some tests have been
given a `norecurse` for now.
With D106397 we ensured that `AAReachability` will not answer queries for
potentially recursive functions. This was necessary as we did not treat
recursion explicitly otherwise. Now that we have
`AA::isPotentiallyReachable` we can make `AAReachability` a purely
intra-procedural AA which does not care about recursion.
`AA::isPotentiallyReachable`, however, does already deal with "going
back" the call graph and can now do so for potentially recursive
functions.
Add statistics to count overall devirtualized targets as well as the
various types of devirtualizations applied at callsites.
Differential Revision: https://reviews.llvm.org/D123152
If we ignore droppable users everything only used in llvm.assume (among
other things) is going to be deleted as dead. This is not helpful.
Instead we want to only delete things we actually don't need anymore. A
follow up will deal with loads in a smarter way.
When simplify values we might end up with an instruction from a
different scope or just one that does not dominate the use. If the
instruction can be reproduced without side-effect (incl. UB) we can
now do that. For now this is mostly used for speculatable (intrinsic)
calls but as we learn to make things like arguments or loads available
this will become more powerful.
This will also allow us to remove dead stores more easily in a follow
up.
I didn't dig into this very much because it appears to be totally valid
(especially once these properties can come from attributes instead
of only from hard-coded library functions) for TLI to not be defined,
and nothing broke when I added this check, including with all my other
patches applied.
Differential Revision: https://reviews.llvm.org/D122917
This isn't expected to reduce compilation times as 'max-iters' is set to
one by default, but it helps with recursive functions that require higher
iteration counts.
Differential Revision: https://reviews.llvm.org/D122819
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
This fixes a TODO in constantArgPropagation() to make it feature complete.
However, I do find myself in agreement with the review comments in
https://reviews.llvm.org/D106426. I don't think we should pursue
specializing such recursive functions as the code size increase becomes
linear to 'max-iters'. Compiling the modified test just with -O3 (no
function specialization) generates the same code.
Differential Revision: https://reviews.llvm.org/D122755
Inline assembly is scary but we need to support it for the OpenMP GPU
device runtime. The new assumption expresses the fact that it may not
have call semantics, that is, it will not call another function but
simply perform an operation or side-effect. This is important for
reachability in the presence of inline assembly.
Differential Revision: https://reviews.llvm.org/D109986
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
This was reusing a cast to GlobalVariable to check for an
Instruction, which means we'll try to dereference a null pointer
if it's not actually a GlobalVariable. We should be casting
MTI->getSource() instead.
I don't think this problem is really specific to opaque pointers,
but it certainly makes it a lot easier to reproduce.
Fixes https://github.com/llvm/llvm-project/issues/54572.
The current implementation of Function Specialization does not allow
specializing more than one arguments per function call, which is a
limitation I am lifting with this patch.
My main challenge was to choose the most suitable ADT for storing the
specializations. We need an associative container for binding all the
actual arguments of a specialization to the function call. We also
need a consistent iteration order across executions. Lastly we want
to be able to sort the entries by Gain and reject the least profitable
ones.
MapVector fits the bill but not quite; erasing elements is expensive
and using stable_sort messes up the indices to the underlying vector.
I am therefore using the underlying vector directly after calculating
the Gain.
Differential Revision: https://reviews.llvm.org/D119880
Probe-based profile leads to a better performance when combined with profi and ext-tsp block layout. I'm turning them on by default.
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D122442
Most intrinsics, especially "default" ones, will not call back into the
IR module. `nocallback` encodes this nicely. As it was not used before,
this patch also makes use of `nocallback` in the Attributor which
results in many more `norecurse` deductions.
Tablegen part is mechanical, test updates by script.
Differential Revision: https://reviews.llvm.org/D118680
There is potential for endless recursion if we try to determine the
underlying objects of a load, just to end up with the load as underlying
object. A proper solution will require us to pass a visited set around.
This will happen as we cleanup genericValueTraversal soon.
When --disable-sample-loader-inlining is true, skip inline transformation, but merge profiles of inlined instances to outlining versions.
Differential Revision: https://reviews.llvm.org/D121862
When outlining a phi node, if the the incoming branch is a block contained in the region and the branch from that block is not outlined, we create broken code. The fix is to recognize when that branch from the included incoming block is not contained, and ignore the region.
Reviewer: paquette
Differential Revision: https://reviews.llvm.org/D121311
Since the IROutliner is performing an optimization, it should not outline from functions explicitly marked with optnone. This adds an extra check and test to make sure this does not occur.
Reviewers: paquette
Differential Revision: https://reviews.llvm.org/D121567
With debug information enabled (-g) Clang will wrap the actual target
region into a new function which is called from the "kernel". The problem
is that the "kernel" is now basically a wrapper without all the things
we expect. More importantly, if we end up asking for an AAKernelInfo
for the "target region function" we might try to turn it into SPMD mode.
That used to cause an assertion as that function doesn't have an
appropriately named `_exec_mode` global. While the global is going away
soon we still need to make sure to properly handle this case, e.g.,
perform optimizations reliably.
Differential Revision: https://reviews.llvm.org/D122043
Generalize D99629 for ELF. A default visibility non-local symbol is preemptible
in a -shared link. `isInterposable` is an insufficient condition.
Moreover, a non-preemptible alias may be referenced in a sub constant expression
which intends to lower to a PC-relative relocation. Replacing the alias with a
preemptible aliasee may introduce a linker error.
Respect dso_preemptable and suppress optimization to fix the abose issues. With
the change, `alias = 345` will not be rewritten to use aliasee in a `-fpic`
compile.
```
int aliasee;
extern int alias __attribute__((alias("aliasee"), visibility("hidden")));
void foo() { alias = 345; } // intended to access the local copy
```
While here, refine the condition for the alias as well.
For some binary formats like COFF, `isInterposable` is a sufficient condition.
But I think canonicalization for the changed case has little advantage, so I
don't bother to add the `Triple(M.getTargetTriple()).isOSBinFormatELF()` or
`getPICLevel/getPIELevel` complexity.
For instrumentations, it's recommended not to create aliases that refer to
globals that have a weak linkage or is preemptible. However, the following is
supported and the IR needs to handle such cases.
```
int aliasee __attribute__((weak));
extern int alias __attribute__((alias("aliasee")));
```
There are other places where GlobalAlias isInterposable usage may need to be
fixed.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D107249
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Differential Revision: https://reviews.llvm.org/D115907
Failures in `InlineFunction()` are caught after D121722, but `emitInlinedIntoBasedOnCost()` should only be called when inlining is successful. This also removes an unnecessary call to `shouldInline()` which always returned `InlineCost::getAlways()`.
Reviewed By: kyulee, nikic
Differential Revision: https://reviews.llvm.org/D121946
When we build clang without asserts we should still check the result of
`InlineFunction()` to be sure there wasn't an error. Otherwise we could
incorrectly merge attributes in the next line.
This also removes a redundent call to `getCaller()`.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D121722
This patch adds initial argmemonly inference, by checking the underlying
objects of locations returned by MemoryLocation.
I think this should cover most cases, except function calls to other
argmemonly functions.
I'm not sure if there's a reason why we don't infer those yet.
Additional argmemonly can improve codegen in some cases. It also makes
it easier to come up with a C reproducer for 7662d1687b (already fixed,
but I'm trying to see if C/C++ fuzzing could help to uncover similar
issues.)
Compile-time impact:
NewPM-O3: +0.01%
NewPM-ReleaseThinLTO: +0.03%
NewPM-ReleaseLTO+g: +0.05%
https://llvm-compile-time-tracker.com/compare.php?from=067c035012fc061ad6378458774ac2df117283c6&to=fe209d4aab5b593bd62d18c0876732ddcca1614d&stat=instructions
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D121415
Update FunctionAttrs to use FunctionModRefBehavior instead
MemoryAccessKind.
This allows for adding support for inferring argmemonly and others,
see D121415.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D121460
Hardcode the function type as ParallelTask, which is the guaranteed
pointee type of this runtime function argument (if pointee types
exist). The elimination of the callee bitcast is left for InstCombine.
Differential Revision: https://reviews.llvm.org/D120885
When matching PHINodes when margining functions the IROutliner only checks that an incoming value exists in phi node in overall function. It doesn't check the length, the order, or that the incoming block also matches. In the given example, we see that both phi nodes have the same incoming values, but from different blocks.
The fix is to to enforce stricter a match of the incoming value, and the incoming block as well when matching the created phi nodes.
Reviewers: paquette
Differential Revision: https://reviews.llvm.org/D121310
2 of the 3 callsite of IRMover::move() pass empty lambda functions. Just
make this parameter llvm::unique_function.
Came about via discussion in D120781. Probably worth making this change
regardless of the resolution of D120781.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D121630
The IR Outliner is supposed to extract the outputs contained in an external phi node and place them into a phi node contained within the outlined function. However, when the output values of two outlined functions with two different output sets are contained within the same phi node, they are counted as the same exit path when first analyzed. In reality, these create two different phi nodes, creating an inconsistency, resulting in a mismatch in the expected number of output paths and a crash. This fixes that counting when analyzing the outputs by also analyzing the incoming blocks rather than just the incoming values.
Reviewer: paquette
Differential Revision: https://reviews.llvm.org/D121313
Extend -wholeprogramdevirt-check to support both the existing
trapping mode on an incorrect devirtualization, as well as a new
mode to fallback to an indirect call on a mismatch. The new mode is
The new mode is useful in cases where we want to enable
devirtualization but cannot fully guarantee whole program visibility
(e.g in the case where LTO has been disabled for a small set of objects
that could potentially override virtual methods without having a symbol
reference to anything in the base class including the vtable).
Remove !prof and !callees metadata (which are used by indirect call
promotion) from both the new direct call and the fallback indirect call
(so that we don't perform another round of promotion on the latter).
Also remove it from the direct call in the non-fallback cases, which
was an oversight, although it didn't seem to cause any issues. Add tests
for the metadata removal covering the various cases.
Differential Revision: https://reviews.llvm.org/D121419
When there are two external phi nodes for two different outlined regions, when compressing the created phi nodes between the two regions, the matching for the second phi node in the second region matches the first phi node created for the first region rather than the second phi node created for the first region. This adds an extra output path where there should not be one.
The fix is the ignore phi nodes that have already been matched for each region.
Reviewer: paquette
Differential Revision: https://reviews.llvm.org/D121312
Before we used the capture tracker to follow pointer uses, now we do it
explicitly ourselves through the Attributor API. There are multiple
benefits: For one, the boilerplate is cut down by a lot. The class,
potential copies vector, etc. is all not needed anymore. We also do
avoid explicitly looking through memory here, something that was
duplicated and should only live in the `checkForAllUses~ helper. More
importantly, as we do simplifications we need to make sure all parties
are in sync when they reason about uses. The old way did not allow us to
do this but the new one does as every use visiting AA goes through
`checkForAllUses` now..
As replacements will become more complex it is better to have a single
AA responsible for replacing a use. Before this patch AAValueSimplify*
and AAValueSimplifyReturned could both try to replace the returned
value. The latter was marginally better for the old pass manager
when a function was already carrying a `returned` attribute and when
the context of the return instruction was important. The second
shortcoming was resolved by looking for return attributes in the
AAValueSimplifyCallSiteReturned initialization. The old PM impact is
not concerning.
This is yet another step towards the removal of AAReturnedValues, the
very first AA we should now try to eliminate due to the overlapping
logic with value simplification.
When we look through memory for a store we used to allow any other use
of the memory that is reachable. This is generally OK but we need to
make sure to actually let the user look at these properly. For now,
we simply require loads (via exact reloads).
There was some ad-hoc handling of liveness and manifest to avoid
breaking CGSCC guarantees. Things always slipped through though.
This cleanup will:
1) Prevent us from manifesting any "information" outside the CGSCC.
This might be too conservative but we need to opt-in to annotation
not try to avoid some problematic ones.
2) Avoid running any liveness analysis outside the CGSCC. We did have
some AAIsDeadFunction handling to this end but we need this for all
AAIsDead classes. The reason is that AAIsDead information is only
correct if we actually manifest it, since we don't (see point 1) we
cannot actually derive/use it at all. We are currently trying to
avoid running any AA updates outside the CGSCC but that seems to
impact things quite a bit.
3) Assert, don't check, that our modifications (during cleanup) modifies
only CGSCC functions.
In an attempt to remove the memory leak we introduced a double free.
The problem was that we allowed a plain copy of the state and it was
actually used. The use was useless, so it is gone now. The copy
constructor is gone as well. The move constructor ensures the Accesses
pointers are owned by a single state, I hope.
Reported by: https://lab.llvm.org/buildbot/#/builders/16/builds/25820
Arthur Eubanks