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[Clang][CodeGen] Use poison instead of undef for extra argument in __builtin_amdgcn_mov_dpp [NFC]
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Authored by ManuelJBrito on Nov 27 2022, 3:55 AM.

Details

Summary

Use poison instead of undef when emitting llvm.amdgcn.update.dpp for __builtin_amdgcn_mov_dpp.

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ManuelJBrito created this revision.Nov 27 2022, 3:55 AM
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ManuelJBrito requested review of this revision.Nov 27 2022, 3:55 AM
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Couldn't find documentation for this intrinsic, can you shed a light on whether or not this change is OK?

ManuelJBrito edited reviewers, added: arsenm; removed: yaxunl.Dec 6 2022, 3:51 AM

Is this change OK? It seems to me that here undef is just a placeholder. Was hoping that some AMDGPU folks could review it.

arsenm accepted this revision.Dec 6 2022, 4:23 AM

I think this is OK. It’s use of uninitialized value, those uninitialized values just happen to come from inactive lanes.

This revision is now accepted and ready to land.Dec 6 2022, 4:23 AM
This revision was landed with ongoing or failed builds.Dec 6 2022, 4:41 AM
This revision was automatically updated to reflect the committed changes.

Thanks for the review arsenm!