[AArch64] canCreateUndefOrPoisonForTargetNode - AArch64ISD::MOVI opcodes can't create undef/poison #149323
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…des can't create undef/poison Possible fix for failed fold in llvm#148191
RKSimon
commented
Jul 17, 2025
| case AArch64ISD::MOVIedit: | ||
| case AArch64ISD::MOVImsl: | ||
| case AArch64ISD::MOVIshift: | ||
| case AArch64ISD::MVNIshift: |
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In fact I think these can be put into a AArch64TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode implementation, but this should have the same effect
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That sounds OK to me, they should never be poison. Do we have a standard way of creating tests for changes like this?
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It might be that #148191 is the first case where we manage to show the problem (we need a case where the freeze needs removing quite late into lowering) - I haven't had time to investigate though.
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Possible fix for failed fold in #148191