[all-commits] [llvm/llvm-project] 432720: [GlobalISel] Combine sext([sz]ext) -> [sz]ext, zex...

[Dominik Montada via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 432720f1c4c6b47edfb475f8616e471d14c26974
      https://github.com/llvm/llvm-project/commit/432720f1c4c6b47edfb475f8616e471d14c26974
  Author: Dominik Montada <dominik.montada at hightec-rt.com>
  Date:   2020-04-08 (Wed, 08 Apr 2020)

  Changed paths:
    M llvm/include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
    M llvm/test/CodeGen/AMDGPU/GlobalISel/combine-ext-legalizer.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-saddo.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-ssubo.mir

  Log Message:
  -----------
  [GlobalISel] Combine sext([sz]ext) -> [sz]ext, zext(zext) -> zext

Summary:
Combine sext(zext x) to (zext x) since the sign-bit is 0
after the zero-extension.

Combine sext(sext x) to (sext x) and ext(zext x) to (zext x)
since the intermediate step is not needed.

Reviewers: arsenm, volkan, aemerson, aditya_nandakumar

Reviewed By: arsenm

Subscribers: jvesely, wdng, nhaehnle, rovka, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77210