32919 Commits

Author SHA1 Message Date
Florian Hahn
f61c9b7569
[SLP] Fix infinite loop in isUndefVector.
This fixes an infinite loop if isa<T>(II->getOperand(1)) is true.
Update Base at the top of the loop, before the continue.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D144292
2023-02-19 21:42:24 +00:00
Kazu Hirata
cbde2124f1 Use APInt::popcount instead of APInt::countPopulation (NFC)
This is for consistency with the C++20-style bit manipulation
functions in <bit>.
2023-02-19 11:29:12 -08:00
Florian Hahn
7737c05696
[VPlan] Make sure properlyDominates(A, A) returns false.
At the moment, properlyDominates(A, A) can return true via
LocalComesBefore. Add an early exit to ensure it returns false if
A == B.

Note: no test has been added because the existing test suite covers this
case already with libc++ with assertions enabled.

Fixes https://github.com/llvm/llvm-project/issues/60850.
2023-02-19 18:01:16 +00:00
DianQK
1235ed9133
Revert "[SimplifyCFG] Check if the return instruction causes undefined behavior"
This reverts commit b6eed9a82e0ce530d94a194c88615d6c272e1854.
2023-02-19 21:08:29 +08:00
DianQK
b6eed9a82e
[SimplifyCFG] Check if the return instruction causes undefined behavior
This should fix https://github.com/rust-lang/rust/issues/107681.

Return undefined to a noundef return value is undefined.

Example:

```
define noundef i32 @test_ret_noundef(i1 %cond) {
entry:
  br i1 %cond, label %bb1, label %bb2
bb1:
  br label %bb2
bb2:
  %r = phi i32 [ undef, %entry ], [ 1, %bb1 ]
  ret i32 %r
}
```

Differential Revision: https://reviews.llvm.org/D144319
2023-02-19 19:42:40 +08:00
Juneyoung Lee
2ad0cc9186 [DivRemPairs] Strip division's poison generating flag
Given this transformation: X % Y -> X - (X / Y) * Y

This patch strips off the poison-generating flag of X / Y such as exact, because it may make the optimized form result poison whereas X % Y does not.

The issue was reported here: https://github.com/llvm/llvm-project/issues/60748

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D144333
2023-02-18 21:00:55 +00:00
Vitaly Buka
c23f29d6f0 Revert "[SimplifyCFG] Check if the return instruction causes undefined behavior"
Breaks bots
https://lab.llvm.org/buildbot/#/builders/236/builds/2349
https://lab.llvm.org/buildbot/#/builders/74/builds/17361
https://lab.llvm.org/buildbot/#/builders/168/builds/11972

This reverts commit 7be55b007698f6b6398cbbea69c327b5a971938a.
2023-02-18 12:21:10 -08:00
Florian Hahn
a9a1950115
Revert "[SCCP] Remove legacy SCCP pass."
This reverts commit 5356fefc19df3fbf32d180b1b10e6226e8743541.

It looks like Polly still relies on the legacy SCCP pass. Bring it back
until the best way forward is determined.
2023-02-18 18:01:37 +00:00
Florian Hahn
5356fefc19
[SCCP] Remove legacy SCCP pass.
This is part of the optimization pipeline, of which the legacy pass manager version is deprecated.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D144201
2023-02-18 17:54:30 +00:00
DianQK
7be55b0076
[SimplifyCFG] Check if the return instruction causes undefined behavior
This should fix https://github.com/rust-lang/rust/issues/107681.

Return undefined to a noundef return value is undefined.

Example:

```
define noundef i32 @test_ret_noundef(i1 %cond) {
entry:
  br i1 %cond, label %bb1, label %bb2
bb1:
  br label %bb2
bb2:
  %r = phi i32 [ undef, %entry ], [ 1, %bb1 ]
  ret i32 %r
}
```

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D144319
2023-02-18 23:31:57 +08:00
Paulo Matos
890146b192 [WebAssembly] Initial support for reference type externref in clang
This patch introduces a new type __externref_t that denotes a WebAssembly opaque
reference type. It also implements builtin __builtin_wasm_ref_null_extern(),
that returns a null value of __externref_t. This lays the ground work
for further builtins and reference types.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122215
2023-02-17 18:48:48 -08:00
Matt Arsenault
c42eda5d36 IROutliner: cast instead of dyn_cast and assert 2023-02-17 22:28:09 -04:00
Matt Arsenault
e8444078ed CodeExtractor: Fix creating addrspacecasts for lifetime markers
Also stop caring about typed pointers.
2023-02-17 22:27:29 -04:00
Jan Dupej
1ceb79e2e0 Port PlaceSafepoints pass to the new pass manager
This patch ports the PlaceSafepoints pass to the new pass manager as it is used by .NET/Mono. Compatibility with the legacy pass manager is maintained by adding PlaceSafepointsLegacyPass. This pass also depends on PlaceBackedgeSafepointsLegacyPass, which has been kept in the legacy-only variant, since it is apparently used only from PlaceSafepointsPass. It has been renamed, though, to indicate its legacy interface.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D136163
2023-02-17 09:17:49 -08:00
Sanjay Patel
4ecc6af813 [InstCombine] create a pass options container and add "use-loop-info" argument
This is a cleanup/modernization patch requested in D144045 to make loop
analysis a proper optional parameter to the pass rather than a
semi-arbitrary value inherited via the pass pipeline.

It's a bit more complicated than the recent patch I started copying from
(D143980) because InstCombine already has an option for MaxIterations
(added with D71145).

I debated just deleting that option, but it was used by a pair of existing
tests, so I put it into a struct (code largely copied from SimplifyCFG's
implementation) to make the code more flexible for future options
enhancements.

I didn't alter the pass manager invocations of InstCombine in this patch
because the patch was already getting big, but that will be a small
follow-up as noted with the TODO comment.

Differential Revision: https://reviews.llvm.org/D144199
2023-02-17 10:30:15 -05:00
Alexey Bataev
e03d254bbd [SLP]Do not reduce repeated values, use scalar red ops instead.
Metric: size..text

                                                     size..text                 results     results0    diff
SingleSource/Regression/C/gcc-c-torture/execute/GCC-C-execute-980605-1.test      445.00      461.00  3.6%
SingleSource/Benchmarks/Adobe-C++/loop_unroll.test                               428477.00   428445.00 -0.0%
External/SPEC/CFP2006/447.dealII/447.dealII.test                                 618849.00   618785.00 -0.0%

For all tests some extra code was optimized, GCC-C-execute has some more
inlining after

Differential Revision: https://reviews.llvm.org/D132261
2023-02-17 07:19:35 -08:00
Benjamin Kramer
da3623de24 [JT] Always create BPI/BFI when running in legacy PM
This is wasteful, but only affects the legacy pass manager. Otherwise
a1b78fb929fccf96acaa0212cf68fee82298e747 would crash JT when running
with that PM. There are still a few users of the legacy PM out there
that are reluctant to migrate, numba in this case.

No test as we don't test legacy PM anymore.
2023-02-17 10:13:20 +01:00
Teresa Johnson
8045ba8948 [ThinLTO/WPD] Handle function alias in vtable correctly
We were not summarizing a function alias in the vtable, leading to
incorrect WPD in some cases, and missing WPD in others.

Specifically, we would end up ignoring function aliases as they aren't
summarized, so we could incorrectly devirtualize if there was a single
other non-alias function in a compatible vtable. And if there was only
one implementation, but it was an alias, we would not be able to
identify and perform the single implementation devirtualization.

Handling the alias summary correctly also required fixing the handling
in mustBeUnreachableFunction, so that it is not incorrectly ignored.

Regular LTO is conservatively correct because it will skip
devirtualizing when any pointer within a vtable is not a function.
However, it needs additional work to be able to take advantage of
function alias within the vtable that is in fact the only
implementation. For that reason, the Regular LTO testing in the second
test case is currently disabled, and will be enabled along with a follow
on enhancement fix for Regular LTO WPD.

Differential Revision: https://reviews.llvm.org/D144209
2023-02-16 18:20:12 -08:00
Nick Desaulniers
45a291b5f6 [Dominators] check indirect branches of callbr
This will be necessary to support outputs from asm goto along indirect
edges.

Test via:
  $ pushd llvm/build; ninja IRTests; popd
  $ ./llvm/build/unittests/IR/IRTests \
    --gtest_filter=DominatorTree.CallBrDomination

Also, return nullptr in Instruction::getInsertionPointAfterDef for
CallBrInst as was recommened in
https://reviews.llvm.org/D135997#3991427.  The following phab review was
folded into this commit: https://reviews.llvm.org/D140166

Link: Link: https://discourse.llvm.org/t/rfc-syncing-asm-goto-with-outputs-with-gcc/65453/8

Reviewed By: void, efriedma, ChuanqiXu, MaskRay

Differential Revision: https://reviews.llvm.org/D135997
2023-02-16 17:58:33 -08:00
Johannes Doerfert
7495a2e51b [Attributor][FIX] Ensure we adjust types properly
When we simplify loads we need to adjust types (esp. null-values)
properly to avoid inconsinstencies down the line. Add a cast and an
error message.

Fixes: https://github.com/llvm/llvm-project/issues/60788
2023-02-16 17:45:56 -08:00
Simon Tatham
bbef38352f Revert "[LowerTypeTests] Support generating Armv6-M jump tables."
This reverts commit f6ddf7781471b71243fa3c3ae7c93073f95c7dff.

Eight buildbots reported that the two test files changed by that
commit had started failing. The buildbots in question all had in
common that they build with a very restricted `LLVM_TARGETS_TO_BUILD`,
such as only X86 or AArch64 or Hexagon. I didn't notice this before
commit because my own build has the full default set of targets, and
in that circumstance, the tests pass.

I assume the problem has something to do with the attempt to query
TargetTransformInfo: if you can't make a valid TTI for the target
triple then you can't ask it what kind of inline assembler you should
be emitting, and so `opt` without the Arm backend can't get the Arm
cases of these tests right.

I don't have time to fix this until next week, so I'll revert the
change for now to keep the buildbots happy.
2023-02-16 17:11:06 +00:00
David Green
7abe3497e7 [LSR] Improve filtered uses in NarrowSearchSpaceByPickingWinnerRegs
NarrowSearchSpaceByPickingWinnerRegs has an aggressive filtering method to
reduce the complexity of the search space down by picking a best formula with
the highest number of reuses and assuming it will yield profitable reuse. In
certain cases we can find a best formula like {X+30,+,1} and later check a
formula like {X,+,1} with the same number of Uses. On some architectures it
can be better to pick {X,+,1}, especially if an offset of 30 can be used as a
legal addressing mode, but -30 cannot. That happens under Thumb1 code, which
has fairly limited addressing modes. This patch adds a check to see if it can
pick the simpler formula, if it looks more profitable.

Differential Revision: https://reviews.llvm.org/D144014
2023-02-16 15:48:12 +00:00
Simon Tatham
f6ddf77814 [LowerTypeTests] Support generating Armv6-M jump tables.
The LowerTypeTests pass emits a jump table in the form of an
`inlineasm` IR node containing a string representation of some
assembly. It tests the target triple to see what architecture it
should be generating assembly for. But that's not good enough for
`Triple::thumb`, because the 32-bit PC-relative `b.w` branch
instruction isn't available in all supported architecture versions. In
particular, Armv6-M doesn't support that instruction (although the
similar Armv8-M Baseline does).

Most of this patch is concerned with working out whether the
compilation target is Armv6-M or not, which I'm doing by going through
all the functions in the module, retrieving a TargetTransformInfo for
each one, and querying it via a new method I've added to check its
SubtargetInfo. If any function's TTI indicates that it's targeting an
architecture supporting B.W, then we assume we're also allowed to use
B.W in the jump table.

The Armv6-M compatible jump table format requires a temporary
register, and therefore also has to use the stack in order to restore
that register.

Another consequence of this change is that jump tables on Arm/Thumb
are no longer always the same size. In particular, on an architecture
that supports Arm and Thumb-1 but not Thumb-2, the Arm and Thumb
tables are different sizes from //each other//. As a consequence,
``getJumpTableEntrySize`` can no longer base its answer on the target
triple's architecture: it has to take into account the decision that
``selectJumpTableArmEncoding`` made, which meant I had to move that
function to an earlier point in the code and store its answer in the
``LowerTypeTestsModule`` class.

Reviewed By: lenary

Differential Revision: https://reviews.llvm.org/D143576
2023-02-16 15:34:49 +00:00
Florian Hahn
a3d1de3e29
[LV] Move invalid cost remark code to separate function (NFC).
The code only needs access to INvalidCosts, ORE and TheLoop, so it can
easily be moved into a helper to make selectVectorizationFactor more
compact.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D143957
2023-02-16 11:28:19 +00:00
Evgeniy Brevnov
a1b78fb929 [JT][CT] Preserve exisiting BPI/BFI during JumpThreading
Currently, JT creates and updates local instances of BPI\BFI. As a result global ones have to be invalidated if JT made any changes.
In fact, JT doesn't use any information from BPI/BFI for the sake of the transformation itself. It only creates BPI/BFI to keep them up to date. But since it updates local copies (besides cases when it updates profile metadata) it just waste of time.

Current patch is a rework of D124439. D124439 makes one step and replaces local copies with global ones retrieved through AnalysisPassManager. Here we do one more step and don't create BPI/BFI if the only reason of creation is to keep BPI/BFI up to date. Overall logic is the following. If there is cached BPI/BFI then update it along the transformations. If there is no existing BPI/BFI, then create it only if it is required to update profile metadata.

Please note if BPI/BFI exists on exit from JT (either cached or created) it is always up to date and no reason to invalidate it.

Reviewed By: mkazantsev

Differential Revision: https://reviews.llvm.org/D136827
2023-02-16 16:08:34 +07:00
Nikita Popov
c9fad20f6a [InstCombine] Call simplifyInsertValueInst()
InstCombine is supposed to be a superset of InstSimplify, but we
were not attempting simplification of insertvalue instructions.
As the test change illustrates, we failed to remove some aggregate
construction patterns because of that.
2023-02-16 09:51:40 +01:00
Fangrui Song
f62b084e92 [LoopDeletion] Remove legacy pass
Following recent changes to remove non-core legacy passes.
2023-02-15 23:31:05 -08:00
Kazu Hirata
7e6e636fb6 Use llvm::has_single_bit<uint32_t> (NFC)
This patch replaces isPowerOf2_32 with llvm::has_single_bit<uint32_t>
where the argument is wider than uint32_t.
2023-02-15 22:17:27 -08:00
Fangrui Song
4eee77873b [LoopReroll] Remove legacy pass (unused in the pipeline)
Following recent changes to remove non-core legacy passes.
2023-02-15 16:09:32 -08:00
Fangrui Song
e7d3f43eaf [LoopFlatten] Inline an external linkage function not in llvm::. NFC 2023-02-15 15:40:34 -08:00
Fangrui Song
48bfed77cf [LoopFlatten] Remove legacy pass (unused in the pipeline)
Following recent changes to remove non-core legacy passes.
2023-02-15 15:28:16 -08:00
Fangrui Song
21ccddd2ce [LoopInterchange] Remove legacy pass (unused in the pipeline)
Following recent changes to remove non-core legacy passes.
2023-02-15 15:09:29 -08:00
Hongtao Yu
eddec9de44 [Pseudo probe] Duplicate probes in vectorized loop body.
Prevoius pseudo probes were dropped out of a vectorized loop body during loop vectorization. This can result in the samples of the loop entry is used for the loop body, which in turn can cause undercounting of the loop iteration count. The undercounting can further prevent the loop from being vectorized in the next build. I'm fixing this by explicting allowing pseudo probes to be kept in the vectorized loop body, and by claiming a probe instruction is not "uniform", the vectorizer will duplicate it by the number of vector lanes.

For one internal service, I'm seeing the change causes the size increase of the .pseudoprobe section by 0.7%, which should count around 0.2% of the whole binary size.

Reviewed By: wenlei

Differential Revision: https://reviews.llvm.org/D144066
2023-02-15 10:18:08 -08:00
Zain Jaffal
07f93d8c2c Recommit "[ConstraintElimination] Change debug output to display variable names."
This reverts commit 02ae7e72b3f00969eeb579a2b4346082827f0b35.

include Value.h in ConstraintSystem.h
2023-02-15 16:38:35 +00:00
Nikita Popov
02ae7e72b3 Revert "Recommit "[ConstraintElimination] Change debug output to display variable names.""
This reverts commit 2a2a6bfcfe8e62886542cb673ac8df349cf26499.

This causes build failures:

    /home/npopov/repos/llvm-project/llvm/lib/Analysis/ConstraintSystem.cpp: In member function ‘llvm::SmallVector<std::__cxx11::basic_string<char> > llvm::ConstraintSystem::getVarNamesList() const’:
    /home/npopov/repos/llvm-project/llvm/lib/Analysis/ConstraintSystem.cpp:118:10: error: invalid use of incomplete type ‘class llvm::Value’
      118 |     if (V->getName().empty())
          |          ^~
    In file included from /home/npopov/repos/llvm-project/llvm/lib/Analysis/ConstraintSystem.cpp:9:
    /home/npopov/repos/llvm-project/llvm/include/llvm/Analysis/ConstraintSystem.h:21:7: note: forward declaration of ‘class llvm::Value’
       21 | class Value;
          |       ^~~~~
    /home/npopov/repos/llvm-project/llvm/lib/Analysis/ConstraintSystem.cpp:119:22: error: invalid use of incomplete type ‘class llvm::Value’
      119 |       OperandName = V->getNameOrAsOperand();
          |                      ^~
    /home/npopov/repos/llvm-project/llvm/include/llvm/Analysis/ConstraintSystem.h:21:7: note: forward declaration of ‘class llvm::Value’
       21 | class Value;
          |       ^~~~~
    /home/npopov/repos/llvm-project/llvm/lib/Analysis/ConstraintSystem.cpp:121:41: error: invalid use of incomplete type ‘class llvm::Value’
      121 |       OperandName = std::string("%") + V->getName().str();
          |                                         ^~
    /home/npopov/repos/llvm-project/llvm/include/llvm/Analysis/ConstraintSystem.h:21:7: note: forward declaration of ‘class llvm::Value’
       21 | class Value;
          |       ^~~~~
2023-02-15 16:36:44 +01:00
Zain Jaffal
2a2a6bfcfe Recommit "[ConstraintElimination] Change debug output to display variable names."
This reverts commit 62d0e1a8541f93dfbf66d982f66da32676df2df7.

remove `dumpWithNames` function
2023-02-15 15:23:53 +00:00
Zain Jaffal
62d0e1a854 Revert "[ConstraintElimination] Change debug output to display variable names."
This reverts commit 869c87ad10e87db7c032c3464338ab9d50916510.

`dumpWithNames` function should be removed
2023-02-15 15:21:46 +00:00
Zain Jaffal
869c87ad10 [ConstraintElimination] Change debug output to display variable names.
Previously when constraint system outputs the rows in the system the variables used are x1,2...n making it hard to infer which ones they relate to in the IR

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D142618
2023-02-15 15:07:48 +00:00
Max Kazantsev
3600b38446 [SimpleLoopUnswitch] Canonicalize conditions for injection of invariant condition
When loop condition isn't immediately in the form supported by invariant injection
unswitching, try to canonicalize it to this form.

Differential Revision: https://reviews.llvm.org/D143175
Reviewed By: skatkov
2023-02-15 18:15:24 +07:00
Max Kazantsev
bc173f526c [SimpleLoopUnswitch] Fix overflowing frequencies case
When branch is so hot that sum of its frequencies overflows, we have an assertion
failure when trying to construct BranchProbability. Such cases are not interesting
as candidate for unswitching anyways (their branches are too hot), so reject them.
2023-02-15 17:40:53 +07:00
Matt Arsenault
458ad6900e Revert "InstCombine: Fold is.fpclass(x, fcZero) to fcmp oeq 0"
This reverts commit df78976d023a6b7fcf64bc695261b7b402fcede0.

I pushed the wrong patch
2023-02-15 05:27:26 -04:00
Matt Arsenault
df78976d02 InstCombine: Fold is.fpclass(x, fcZero) to fcmp oeq 0
This requires the denormal mode to definitively be IEEE handling.
2023-02-15 05:21:00 -04:00
Sander de Smalen
462227f115 [SROA] NFC: Look at TypeStoreSize scalable property, rather than at type directly.
Some places in the code have checks for isa<ScalableVectorType> and use
that to bail out of the code. It's also possible to look directly at the
allocated type-size and check if the size is scalable. This means it's
possible to also support other scalable types that are not vectors (i.e.
TargetExtType).

This is split out from D136861.
2023-02-15 09:01:14 +00:00
Max Kazantsev
86a63b2ae1 [Metarenamer] Use 'inst' as default name for instructions
Currently we use 'tmp', which is also a keyword for FileCheck. It leads to this
annoying warning whenever a script for auto-generation of checks is used.
It is especially annoying that it happens to every test affected by metarenamer.

Just use another prefix for metarenamed names to avoid this.

Differential Revision: https://reviews.llvm.org/D144001
Reviewed By: nikic
2023-02-15 15:35:25 +07:00
Fangrui Song
c1eb3db780 [LoopFuse] Remove legacy pass
Following recent changes to remove non-core legacy passes.
2023-02-14 23:53:39 -08:00
Craig Topper
2872987e5e [InstCombine] Fix InstCombinerImpl::foldICmpMulConstant for nsw and nuw mul with unsigned compare.
If we have both an nsw and nuw flag, we would see the nsw flag
first and only handle signed comparisons.

This patch ignores the nsw flag if the comparison isn't signed.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D143766
2023-02-14 23:43:17 -08:00
Fangrui Song
a409f3c069 [LoopVersioningLICM] Remove legacy pass
Following recent changes to remove non-core features of the legacy PM/optimization pipeline.
2023-02-14 21:40:45 -08:00
Kazu Hirata
4dfd5a3eb6 [llvm] Use std::optional instead of llvm::Optional (NFC)
This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-02-14 20:27:41 -08:00
chenglin.bi
dd31a3b3a5 [InstCombine] fold icmp of the sum of ext bool based on limited range
For the pattern `(zext i1 X) + (sext i1 Y)`, the constant range is [-1, 1].
We can simplify the pattern by logical operations. Like:

```
    (zext i1 X) + (sext i1 Y) == -1 -->  ~X & Y
    (zext i1 X) + (sext i1 Y) == 0  --> ~(X ^ Y)
    (zext i1 X) + (sext i1 Y) == 1 --> X & ~Y
```
And other predicates can the combination of these results:

```
    (zext i1 X) + (sext i1 Y)) != -1 --> X | ~Y
    (zext i1 X) + (sext i1 Y)) s> -1 --> X | ~Y
    (zext i1 X) + (sext i1 Y)) u< -1 --> X | ~Y
    (zext i1 X) + (sext i1 Y)) s> 0 --> X & ~Y
    (zext i1 X) + (sext i1 Y)) s< 0 --> ~X & Y
    (zext i1 X) + (sext i1 Y)) != 1 --> ~X | Y
    (zext i1 X) + (sext i1 Y)) s< 1 --> ~X | Y
    (zext i1 X) + (sext i1 Y)) u> 1 --> ~X & Y
```

All alive proofs:
https://alive2.llvm.org/ce/z/KmgDpF
https://alive2.llvm.org/ce/z/fLwWa9
https://alive2.llvm.org/ce/z/ZKQn2P

Fix: https://github.com/llvm/llvm-project/issues/59666

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D143373
2023-02-15 10:34:00 +08:00
Liren Peng
06f06644ef [SeparateConstOffsetFromGEP] Fix: b - a matched a - b during reuniteExts
During the SeparateConstOffsetFromGEP pass, a - b and b - a will be
considered equivalent in some instances.

An example- the IR contains:

  BB1:
      %add = add %a, 511
      br label %BB2
  BB2:
      %sub2 = sub %b,  %a
      br label %BB3
  BB3:
      %sub1 = sub %add, %b
      %gep = getelementptr float, ptr %p, %sub1

Step 1 in the SeparateConstOffsetFromGEP pass, after split constant index:

  BB1:
      %add = add %a, 511
      br label %BB2
  BB2:
      %sub2 = sub %b,  %a
      br label %BB3
  BB3:
      %sub.t = sub %a, %b
      %gep.base = getelementptr float, ptr %p, %sub.t
      %gep = getelementptr float, ptr %gep.base, 511

Step 2, after reuniteExts:

  BB1:
      br label %BB2
  BB2:
      %sub2 = sub %b,  %a
      br label %BB3
  BB3:
      %gep.base = getelementptr float, ptr %p, %sub2
      %gep = getelementptr float, ptr %gep.base, 511

Obviously, reuniteExts treated a - b and b - a as equivalent.
This patch fixes that.

Reviewed By: nikic, spatel

Differential Revision: https://reviews.llvm.org/D143542
2023-02-15 02:33:31 +00:00