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Merged
merged 1 commit into from
Nov 20, 2023
Merged

feat: fix big endian shuffle vector miscompile #68673

merged 1 commit into from
Nov 20, 2023

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hstk30-hw
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fix #65884

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github-actions bot commented Oct 10, 2023 •
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✅ With the latest revision this PR passed the C/C++ code formatter.

davemgreen
davemgreen reviewed Oct 10, 2023
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@hstk30-hw hstk30-hw force-pushed the fix_be_shuffle_vector_miscompile branch 3 times, most recently from b0d9595 to ec74c1e Compare October 12, 2023 08:36
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Also - AArch64ISD::NVCAST == ISD::BITCAST under LE, so it can be used in both cases.

@hstk30-hw hstk30-hw force-pushed the fix_be_shuffle_vector_miscompile branch from ec74c1e to 7f20eab Compare October 12, 2023 12:53
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It looks like there might be a few failing tests, possibly that need updating?

It is possible that there are a number of places where bitcast is being used incorrectly under BE.

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Yes，I need time to check it. Some tests are hard to check manually, it seem generates automatilly for be.

@hstk30-hw hstk30-hw force-pushed the fix_be_shuffle_vector_miscompile branch 4 times, most recently from 5162649 to 98bf8f8 Compare November 6, 2023 08:41
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Also - AArch64ISD::NVCAST == ISD::BITCAST under LE, so it can be used in both cases.

Replace ISD::BITCAST to AArch64ISD::NVCAST simply will let this commit: 62fc58a not work.

Check it plz. @davemgreen

@hstk30-hw hstk30-hw requested a review from davemgreen November 8, 2023 01:20
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hstk30-hw commented Nov 13, 2023 •
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Ping ... @davemgreen

@hstk30-hw hstk30-hw closed this Nov 16, 2023
@hstk30-hw hstk30-hw reopened this Nov 16, 2023
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Ping @nikic @ostannard @efriedma-quic

davemgreen
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Hi - sorry about the delay it took a while to look through the details. There might be a way to convert NVCAST to BITCAST under LE and adjust all the needed patterns to handle either, but it doesn't look simple and this seems like a good fix for now. It checked out OK in all the tests I tried. There are some comments about adjusting the new test case below, but otherwise this looks OK to me.

@hstk30-hw hstk30-hw force-pushed the fix_be_shuffle_vector_miscompile branch from 98bf8f8 to 0206a97 Compare November 19, 2023 14:52
davemgreen
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Thanks. LGTM

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"hstk30-hw [email protected]"
Merge it for me, plz.

@davemgreen davemgreen merged commit abcbca2 into llvm:main Nov 20, 2023
sr-tream pushed a commit to sr-tream/llvm-project that referenced this pull request Nov 20, 2023
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[AArch64] Fix big endian shuffle vector miscompile (llvm#68673)
25fa5b3 
Fixes llvm#65884
zahiraam pushed a commit to zahiraam/llvm-project that referenced this pull request Nov 20, 2023
@hstk30-hw @zahiraam
[AArch64] Fix big endian shuffle vector miscompile (llvm#68673)
67a9c37 
Fixes llvm#65884
@ostannard ostannard mentioned this pull request Dec 5, 2024
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[AArch64] neon big endian miscompiled
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