[all-commits] [llvm/llvm-project] 608559: [AMDGPU] simplifyI24 - replace GetDemandedBits wit...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 6085593c128e91fd7db998c5441ebe120c7e4f04
      https://github.com/llvm/llvm-project/commit/6085593c128e91fd7db998c5441ebe120c7e4f04
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-02-20 (Thu, 20 Feb 2020)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    M llvm/test/CodeGen/AMDGPU/amdgpu-mul24-knownbits.ll
    M llvm/test/CodeGen/AMDGPU/lshl64-to-32.ll

  Log Message:
  -----------
  [AMDGPU] simplifyI24 - replace GetDemandedBits with SimplifyMultipleUseDemandedBits

GetDemandedBits mostly just calls SimplifyMultipleUseDemandedBits now, but it does a very blunt constant simplification that SimplifyMultipleUseDemandedBits avoids.

If we need to demand bits from constants we should handle this through ShrinkDemandedConstant/targetShrinkDemandedConstant.

@arsenm confirmed that the sign extended immediates are better for code size.

Differential Revision: https://reviews.llvm.org/D74857