[PATCH] D90774: [AArch64][GlobalISel] Fold G_XOR x, -1 into G_SELECT and select CSINV

[Jessica Paquette via Phabricator via llvm-commits]

paquette created this revision.
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When we see

  xor = G_XOR xor_lhs, -1
  select = G_SELECT cc, tval, xor

Fold this into

  select = CSINV tval, xor_lhs, cc

Update select-select.mir to reflect the changes.

For now, only handle the case where the G_XOR is the false-value for the G_SELECT. It may make more sense to handle the true-value case in post-legalizer lowering.


https://reviews.llvm.org/D90774

Files:
  llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/select-select.mir

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