Refactored __tgt_target_data_begin_mapper_<issue|wait> to receive the handle as an input/output argument.
This given the compiler warning of returning the handle as copy.
Differential Revision: https://reviews.llvm.org/D88029
https://bugs.llvm.org/show_bug.cgi?id=45932
assert(OutlinedFunctionCost >= Cloner.OutlinedRegionCost && "Outlined function cost should be no less than the outlined region") getting triggered in computeBBInlineCost.
Intrinsics like "assume" are considered regular function calls while computing costs.
This patch enables computeBBInlineCost to queries TTI for intrinsic call cost.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D87132
This patch is a first draft of a new pass that adds a more flexible way
to eliminate compares based on more complex constraints collected from
dominating conditions.
In particular, it aims at simplifying conditions of the forms below
using a forward propagation approach, rather than instcomine-style
ad-hoc backwards walking of def-use chains.
if (x < y)
if (y < z)
if (x < z) <- simplify
or
if (x + 2 < y)
if (x + 1 < y) <- simplify assuming no wraps
The general approach is to collect conditions and blocks, sort them by
dominance and then iterate over the sorted list. Conditions are turned
into a linear inequality and add it to a system containing the linear
inequalities that hold on entry to the block. For blocks, we check each
compare against the system and see if it is implied by the constraints
in the system.
We also keep a stack of processed conditions and remove conditions from
the stack and the constraint system once they go out-of-scope (= do not
dominate the current block any longer).
Currently there still are the least the following areas for improvements
* Currently large unsigned constants cannot be added to the system
(coefficients must be represented as integers)
* The way constraints are managed currently is not very optimized.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D84547
The argument promotion pass currently fails to copy function annotations
over to the modified function after promoting arguments.
This patch copies the original function annotation to the new function.
Reviewed By: fhann
Differential Revision: https://reviews.llvm.org/D86630
This patch enables inserting freeze when JumpThreading converts a select to
a conditional branch when it is run in LTO.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D85534
This commit cleans up the ::initialize method of various AAs in the
following ways:
- If an associated function is required, give up on declarations.
This was discovered as a real problem when lots of llvm.dbg.XXX
call sites were assumed `noreturn` until proven otherwise. That
does not make any sense and caused huge regressions and missed
deductions.
- Require more associated declarations for function interface AAs.
- Use the IRAttribute::initialize to determine if function interface
AAs can be used in IPO, don't replicate the checks (especially
isFunctionIPOAmendable) all over the place. Arguably the function
declaration check should be moved to some central place to.
If we have a callback, call site arguments were already associated with
the callback callee. Now we also associate the function with the
callback callee, thus we know ensure that the following holds true (if
all return nonnull):
`getAssociatedArgument()->getParent() == getAssociatedFunction()`
To test this an early exit from
`AAMemoryBehaviorCallSiteArgument::initialize``
is included as well. Without the change to getAssociatedFunction() this
kind of early exit for declarations would cause callback call site
arguments to miss out.
As we handle callback calls we need to disambiguate the call site
argument number from the callee argument number. While always equal in
non-callback calls, a callback comes with a partial parameter-argument
mapping so there is no implicit correspondence. Here we split
`IRPosition::getArgNo()` into two public functions, `getCallSiteArgNo()`
and `getCalleeArgNo()`. Usages are adjusted to pick the right one for
their purpose. This fixed some problems that would have been exposed as
we more aggressively optimize callbacks.
While operand bundles carry unpredictable semantics, we know some of
them and can therefore "ignore" them. In this case we allow to look at
the declaration of `llvm.assume` when asked for the attributes at a call
site. The assume operand bundles we have do not invalidate the
declaration attributes.
We cannot test this in isolation because the llvm.assume attributes are
determined by the parser. However, a follow up patch will provide test
coverage.
In `MultiSource/Benchmarks/tramp3d-v4/tramp3d-v4.cpp` we initialized
attributes until stack frame ~35k caused space to run out. The initial
size 1024 is pretty much random.
The CloneFunctionInto has implicit requirements with regards to the
linkage and visibility of the function. We now update these after we did
the CloneFunctionInto on the copy with the same linkage and visibility
as the original.
Deleting or replacing anything is certainly a modification. This caused
a later assertion in IPSCCP when compiling 400.perlbench with the new PM.
I'm not sure how to test this.
This was reverted in 503deec218
because it caused gigantic increase (3x) in branch mispredictions
in certain benchmarks on certain CPU's,
see https://reviews.llvm.org/D84108#2227365.
It has since been investigated and here are the results:
https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20200907/827578.html
> It's an amazingly severe regression, but it's also all due to branch
> mispredicts (about 3x without this). The code layout looks ok so there's
> probably something else to deal with. I'm not sure there's anything we can
> reasonably do so we'll just have to take the hit for now and wait for
> another code reorganization to make the branch predictor a bit more happy :)
>
> Thanks for giving us some time to investigate and feel free to recommit
> whenever you'd like.
>
> -eric
So let's just reland this.
Original commit message:
I've been looking at missed vectorizations in one codebase.
One particular thing that stands out is that some of the loops
reach vectorizer in a rather mangled form, with weird PHI's,
and some of the loops aren't even in a rotated form.
After taking a more detailed look, that happened because
the loop's headers were too big by then. It is evident that
SimplifyCFG's common code hoisting transform is at fault there,
because the pattern it handles is precisely the unrotated
loop basic block structure.
Surprizingly, `SimplifyCFGOpt::HoistThenElseCodeToIf()` is enabled
by default, and is always run, unlike it's friend, common code sinking
transform, `SinkCommonCodeFromPredecessors()`, which is not enabled
by default and is only run once very late in the pipeline.
I'm proposing to harmonize this, and disable common code hoisting
until //late// in pipeline. Definition of //late// may vary,
here currently i've picked the same one as for code sinking,
but i suppose we could enable it as soon as right after
loop rotation happens.
Experimentation shows that this does indeed unsurprizingly help,
more loops got rotated, although other issues remain elsewhere.
Now, this undoubtedly seriously shakes phase ordering.
This will undoubtedly be a mixed bag in terms of both compile- and
run- time performance, codesize. Since we no longer aggressively
hoist+deduplicate common code, we don't pay the price of said hoisting
(which wasn't big). That may allow more loops to be rotated,
so we pay that price. That, in turn, that may enable all the transforms
that require canonical (rotated) loop form, including but not limited to
vectorization, so we pay that too. And in general, no deduplication means
more [duplicate] instructions going through the optimizations. But there's still
late hoisting, some of them will be caught late.
As per benchmarks i've run {F12360204}, this is mostly within the noise,
there are some small improvements, some small regressions.
One big regression i saw i fixed in rG8d487668d09fb0e4e54f36207f07c1480ffabbfd, but i'm sure
this will expose many more pre-existing missed optimizations, as usual :S
llvm-compile-time-tracker.com thoughts on this:
http://llvm-compile-time-tracker.com/compare.php?from=e40315d2b4ed1e38962a8f33ff151693ed4ada63&to=c8289c0ecbf235da9fb0e3bc052e3c0d6bff5cf9&stat=instructions
* this does regress compile-time by +0.5% geomean (unsurprizingly)
* size impact varies; for ThinLTO it's actually an improvement
The largest fallout appears to be in GVN's load partial redundancy
elimination, it spends *much* more time in
`MemoryDependenceResults::getNonLocalPointerDependency()`.
Non-local `MemoryDependenceResults` is widely-known to be, uh, costly.
There does not appear to be a proper solution to this issue,
other than silencing the compile-time performance regression
by tuning cut-off thresholds in `MemoryDependenceResults`,
at the cost of potentially regressing run-time performance.
D84609 attempts to move in that direction, but the path is unclear
and is going to take some time.
If we look at stats before/after diffs, some excerpts:
* RawSpeed (the target) {F12360200}
* -14 (-73.68%) loops not rotated due to the header size (yay)
* -272 (-0.67%) `"Number of live out of a loop variables"` - good for vectorizer
* -3937 (-64.19%) common instructions hoisted
* +561 (+0.06%) x86 asm instructions
* -2 basic blocks
* +2418 (+0.11%) IR instructions
* vanilla test-suite + RawSpeed + darktable {F12360201}
* -36396 (-65.29%) common instructions hoisted
* +1676 (+0.02%) x86 asm instructions
* +662 (+0.06%) basic blocks
* +4395 (+0.04%) IR instructions
It is likely to be sub-optimal for when optimizing for code size,
so one might want to change tune pipeline by enabling sinking/hoisting
when optimizing for size.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D84108
This reverts commit 503deec218.
When checking call sites, give special handling to indirect call, as the
callee may be unknown and can lead to nullptr dereference later. Assume
conservatively that the ICV always changes in such case.
Reviewed By: sstefan1
Differential Revision: https://reviews.llvm.org/D87104
As far as I am aware, the placement of MergedLoadStoreMotion in the
pipeline is not heavily tuned currently. It seems to not matter much if
we do it after DSE in the LTO pipeline (no binary changes for -O3 -flto
on MultiSource/SPEC2000/SPEC2006). Moving it after DSE however has a
major benefit: MemorySSA is constructed by LICM and is consumed by DSE,
so if MergedLoadStoreMotion happens after DSE, we do not need to
preserve MemorySSA in it.
If there are any concerns with this move, I can also update
MergedLoadStoreMotion to preserve MemorySSA.
This patch together with D86651 (preserve MemSSA in MemCpyOpt) and
D86534 (preserve MemSSA in GVN) are the remaining patches to bring down
compile-time for DSE + MemorySSA to the levels outlined in
http://lists.llvm.org/pipermail/llvm-dev/2020-August/144417.html
Once they land, we should be able to start with flipping the switch on
enabling DSE + MmeorySSA.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D86967
When marking a global variable constant, and simplifying users using
CleanupConstantGlobalUsers(), the pass could incorrectly return false if
there were still some uses left, and no further optimizations was done.
This was caught using the check introduced by D80916.
This fixes PR46749.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D85837
This patch makes it possible for AAUB to use information from AANoUndef.
This is the next patch of D86983
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86984
When the associated value is undef, we immediately forced to indicate a pessimistic fixpoint so far.
This patch changes the initialization to check the attribute given in IR at first and to indicate an optimistic fixpoint when it is given.
This change will enable us to catch , for example, the following case in AAUB.
```
call void @foo(i32 noundef undef)
```
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86983
getValuesInOffloadArrays goes through the offload arrays in __tgt_target_data_begin_mapper getting the values stored in them before the call is issued.
call void @__tgt_target_data_begin_mapper(arg0, arg1,
i8** %offload_baseptrs, i8** %offload_ptrs, i64* %offload_sizes,
...)
Diferential Revision: https://reviews.llvm.org/D86300
The problem with module slice has been addressed in D86319
Introduce two new AAs. AAICVTrackerFunctionReturned which checks if a
function can have a unique ICV value after it is finished, and
AAICVCallSiteReturned which checks AAICVTrackerFunctionReturned for a
call site. This enables us to check the value of a call and if it
changes the ICV. This also changes the approach in
`getReplacementValues()` to a worklist-based approach so we can explore
all relevant BBs.
Differential Revision: https://reviews.llvm.org/D85544
Summary:
The module slice describes which functions we can analyze and transform
while working on an SCC as part of the Attributor-CGSCC pass. So far we
simply restricted it to the SCC.
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D86319
This is the next patch of D86842
When we check `noundef` attribute violation at callsites, we do not have to require `nonnull` in the following two cases.
1. An argument is known to be simplified to undef
2. An argument is known to be dead
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86845
Even though `noundef` IR attribute might be attached to non-void type values, AANoUndef is mistakenly identified for pointer type values only.
This patch fixes that.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86737
This patch fixes AANoUndef manifestation.
We should not manifest noundef for positions that will be changed to undef.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86835
There's a special case in hasAttribute for None when pImpl is null. If pImpl is not null we dispatch to pImpl->hasAttribute which will always return false for Attribute::None.
So if we just want to check for None its sufficient to just check that pImpl is null. Which can even be done inline.
This patch adds a helper for that case which I hope will speed up our getSubtargetImpl implementations.
Differential Revision: https://reviews.llvm.org/D86744
Even if noundef is deduced for a position, we should not manifest it when the position is dead.
This is because the associated values with dead positions are replaced with undef values by AAIsDead.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86565
If we query an AA with `Attributor::getAAFor` in `AbstractAttribute::manifest`, the AA may be updated.
This patch makes use of the phase flag in Attributor, and handle `getAAFor` behavior according to the flag.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86635
Add a new flag that indicates which stage in the process we are in.
This flag is introduced for handling behavior of `getAAFor` according to the stage. (discussed in D86635)
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86678
Currently, an undef value is reduced to 0 when it is added to a set of potential values.
This patch introduces a flag for under values. By this, for example, we can merge two states `{undef}`, `{1}` to `{1}` (because we can reduce the undef to 1).
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85592
and indirect call promotion candidate.
Profile remapping is a feature to match a function in the module with its
profile in sample profile if the function name and the name in profile look
different but are equivalent using given remapping rules. This is a useful
feature to keep the performance stable by specifying some remapping rules
when sampleFDO targets are going through some large scale function signature
change.
However, currently profile remapping support is only valid for outline
function profile in SampleFDO. It cannot match a callee with an inline
instance profile if they have different but equivalent names. We found
that without the support for inline instance profile, remapping is less
effective for some large scale change.
To add that support, before any remapping lookup happens, all the names
in the profile will be inserted into remapper and the Key to the name
mapping will be recorded in a map called NameMap in the remapper. During
name lookup, a Key will be returned for the given name and it will be used
to extract an equivalent name in the profile from NameMap. So with the help
of the NameMap, we can translate any given name to an equivalent name in
the profile if it exists. Whenever we try to match a name in the module to
a name in the profile, we will try the match with the original name first,
and if it doesn't match, we will use the equivalent name got from remapper
to try the match for another time. In this way, the patch can enhance the
profile remapping support for searching inline instance and searching
indirect call promotion candidate.
In a planned large scale change of int64 type (long long) to int64_t (long),
we found the performance of a google internal benchmark degraded by 2% if
nothing was done. If existing profile remapping was enabled, the performance
degradation dropped to 1.2%. If the profile remapping with the current patch
was enabled, the performance degradation further dropped to 0.14% (Note the
experiment was done before searching indirect call promotion candidate was
added. We hope with the remapping support of searching indirect call promotion
candidate, the degradation can drop to 0% in the end. It will be evaluated
post commit).
Differential Revision: https://reviews.llvm.org/D86332
This patch produces an edge-based interface in AAIsDead.
By this, we can query a set of basic blocks that are directly reachable from a given basic block.
This is specifically useful for implementation of AAReachability.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85547
This reverts commit 2e43acfed8.
LLVMCoroutines (the library which contains Coroutines.h) depends on LLVMipo (the
library which contains SampleProfile.cpp). It is inappropriate for
SampleProfile.cpp to depent on Coroutines.h (circular dependency).
The test inverted dependencies as well:
llvm/test/Transforms/Coroutines/coro-inline.ll uses -sample-profile.
summary:
When callee coroutine function is inlined into caller coroutine
function before coro-split pass, llvm will emits "coroutine should
have exactly one defining @llvm.coro.begin". It seems that coro-early
pass can not handle this quiet well.
So we believe that unsplited coroutine function should not be inlined.
This patch fix such issue by not inlining function if it has attribute
"coroutine.presplit" (it means the function has not been splited) to
fix this issue
TestPlan: check-llvm
Reviewed By: wenlei
Differential Revision: https://reviews.llvm.org/D85812
As disscussed in post-commit review starting with
https://reviews.llvm.org/D84108#2227365
while this appears to be mostly a win overall, especially code-size-wise,
this appears to shake //certain// code pattens in a way that is extremely
unfavorable for performance (+30% runtime regression)
on certain CPU's (i personally can't reproduce).
So until the behaviour is better understood, and a path forward is mapped,
let's back this out for now.
This reverts commit 1d51dc38d8.
- Adds a command line option to seed only selected functions.
- Makes seed allow listing exclusive to assertions enabled builds.
Reviewed By: sstefan1
Differential Revision: https://reviews.llvm.org/D86129
Hamilton Tobon Mosquera