[PATCH] D124118: [Peephole-Opt] For one kind of test-after-add pattern, eliminates test if it's correct to do so.

[Mingming Liu via Phabricator via llvm-commits]

mingmingl updated this revision to Diff 425906.
mingmingl marked an inline comment as done.
mingmingl added a comment.

Correct the auto-format a little bit

Before

  // The reason to poison SF bit is that SF bit value could be different
  // in the `AND` and `TEST` operation
  //
  // dest_reg = AND32ri8 src_reg, #imm  # signed bit is not known without
  // peeking at #imm. extended_dest_reg = SUBREG_TO_REG 0, dest_reg, sub_32bit

After

  // The reason to poison SF bit is that SF bit value could be different
  // in the `AND` and `TEST` operation; signed bit is not known for `AND`
  // without peeking at #imm, and is known to be 0 as a result of
  // `TEST64rr`.
  // dest_reg = AND32ri8 src_reg, #imm
  // extended_dest_reg = SUBREG_TO_REG 0, dest_reg, sub_32bit
  // TEST64rr extended_dest_reg, extended_dest_reg,


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124118/new/

https://reviews.llvm.org/D124118

Files:
  llvm/lib/Target/X86/X86InstrInfo.cpp
  llvm/test/CodeGen/X86/peephole-test-after-add.mir

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