[all-commits] [llvm/llvm-project] 3daf7d: [GlobalISel] Allow prelegalizer combiners to have ...

[Amara Emerson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3daf7ddaef0a4ddd99d7299ab7c5882329e99700
      https://github.com/llvm/llvm-project/commit/3daf7ddaef0a4ddd99d7299ab7c5882329e99700
  Author: Amara Emerson <amara at apple.com>
  Date:   2022-10-03 (Mon, 03 Oct 2022)

  Changed paths:
    M llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
    M llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
    M llvm/lib/Target/AArch64/GISel/AArch64O0PreLegalizerCombiner.cpp
    M llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerCombiner.cpp
    M llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
    M llvm/lib/Target/AArch64/GISel/AArch64PreLegalizerCombiner.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUPostLegalizerCombiner.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp
    M llvm/lib/Target/AMDGPU/AMDGPURegBankCombiner.cpp
    M llvm/lib/Target/Mips/MipsPostLegalizerCombiner.cpp
    M llvm/lib/Target/Mips/MipsPreLegalizerCombiner.cpp

  Log Message:
  -----------
  [GlobalISel] Allow prelegalizer combiners to have access to LegalizerInfo.

Before, the isPreLegalize() query in CombinerHelper only checked for the
presence of a LegalizerInfo object. This is problematic when we want to have
a combine actually check for legality in a pre-legalizer combine pass, since
if we pass a LegalizerInfo object to the constructor it causes the combines to
think that we're running *post* legalizer, which isn't true.

This change fixes it to instead check an explicit bool that passes to signal
whether the pass will be run before or after legalization.

Doing so exposed a bug in the extending loads combine, which tried to check for
legality of candidate extending loads if LegalizerInfo was present. Since we
only ran it pre-legalizer and therefore with a null LegalizerInfo, it never
actually ran. Also fixes the legality checks to keep the tests passing.

Differential Revision: https://reviews.llvm.org/D135044