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[X86] Set MaxAtomicSizeInBitsSupported. #75112

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Merged
merged 4 commits into from
Dec 12, 2023
+299 −195
Merged

[X86] Set MaxAtomicSizeInBitsSupported. #75112

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fe53c9d
[X86] Set MaxAtomicSizeInBitsSupported.
jyknight Dec 10, 2023
d9e98b3
Add test-case for oversized atomic.
jyknight Dec 11, 2023
3fb0ffd
Use -mtriple instead of -march in test.
jyknight Dec 12, 2023
6742c98
revert format workflow after test.
jyknight Dec 12, 2023
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2 changes: 1 addition & 1 deletion .github/workflows/pr-code-format.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,6 @@ jobs:
python ./code-format-tools/llvm/utils/git/code-format-helper.py \
--token ${{ secrets.GITHUB_TOKEN }} \
--issue-number $GITHUB_PR_NUMBER \
--start-rev $START_REV \
--start-rev $(git merge-base $START_REV $END_REV) \
--end-rev $END_REV \
--changed-files "$CHANGED_FILES"
10 changes: 5 additions & 5 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Expand Up @@ -142,11 +142,11 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
setLibcallName(RTLIB::POWI_F64, nullptr);
}

// If we don't have cmpxchg8b(meaing this is a 386/486), limit atomic size to
// 32 bits so the AtomicExpandPass will expand it so we don't need cmpxchg8b.
// FIXME: Should we be limiting the atomic size on other configs? Default is
// 1024.
if (!Subtarget.canUseCMPXCHG8B())
if (Subtarget.canUseCMPXCHG16B())
setMaxAtomicSizeInBitsSupported(128);
else if (Subtarget.canUseCMPXCHG8B())
setMaxAtomicSizeInBitsSupported(64);
else
setMaxAtomicSizeInBitsSupported(32);

setMaxDivRemBitWidthSupported(Subtarget.is64Bit() ? 128 : 64);
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