[PATCH] D102038: [AArch64][GlobalISel] Create a new minimal combiner pass just for -O0.

[Amara Emerson via Phabricator via llvm-commits]

aemerson created this revision.
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We never bothered to have a separate set of combines for -O0 in the prelegalizer before. This results in some minor performance hits for a mode where performance isn't a concern (although not regressing code size significantly is still preferable).

Through experiments, I've arrived at a set of combines that gets the most code size improvement at -O0, while reducing the amount of time spent in the combiner by around 25% give or take.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D102038

Files:
  llvm/include/llvm/Target/GlobalISel/Combine.td
  llvm/lib/Target/AArch64/AArch64.h
  llvm/lib/Target/AArch64/AArch64Combine.td
  llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
  llvm/lib/Target/AArch64/CMakeLists.txt
  llvm/lib/Target/AArch64/GISel/AArch64O0PreLegalizerCombiner.cpp
  llvm/lib/Target/AArch64/GISel/AArch64PreLegalizerCombiner.cpp
  llvm/test/CodeGen/AArch64/O0-pipeline.ll
  llvm/test/CodeGen/AArch64/combine-loads.ll

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