[PATCH] D70564: [GlobalISel] LegalizationArtifactCombiner: Fix a bug in tryCombineMerges

[Volkan Keles via Phabricator via llvm-commits]

volkan created this revision.
volkan added reviewers: qcolombet, aditya_nandakumar, aemerson, paquette, arsenm, Petar.Avramovic.
Herald added subscribers: atanasyan, jrtc27, rovka, wdng, sdardis.
Herald added a project: LLVM.
volkan added a comment.

@Petar.Avramovic Could you take a look at the failing Mips tests?


When combining G_UNMERGE_VALUES, we were replacing the destination registers
with the source register of the matching G_MERGE_VALUES. However, this is not
legal if the registers have constraints such as assigned register banks.

This patch adds a simple logic to check if the constraints match. If so,
replace the register. Othwerwise, build a COPY instruction to avoid
losing the register constraints.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D70564

Files:
  llvm/include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
  llvm/test/CodeGen/AArch64/GlobalISel/artifact-combine-merge-with-constraints.mir
  llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/long_ambiguous_chain_s64.ll
  llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/phi.ll
  llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/select.ll
  llvm/test/CodeGen/Mips/GlobalISel/llvm-ir/store.ll
  llvm/test/CodeGen/Mips/GlobalISel/regbankselect/long_ambiguous_chain_s32.mir
  llvm/test/CodeGen/Mips/GlobalISel/regbankselect/long_ambiguous_chain_s64.mir
  llvm/test/CodeGen/Mips/GlobalISel/regbankselect/phi.mir
  llvm/test/CodeGen/Mips/GlobalISel/regbankselect/select.mir
  llvm/test/CodeGen/Mips/GlobalISel/regbankselect/store.mir

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