[all-commits] [llvm/llvm-project] a70bbb: [AMDGPU] Simplify 64-bit division/remainder expansion

[Jay Foad via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a70bbb5f7af051a704a985402ff11a38a5f78984
      https://github.com/llvm/llvm-project/commit/a70bbb5f7af051a704a985402ff11a38a5f78984
  Author: Jay Foad <jay.foad at amd.com>
  Date:   2021-11-12 (Fri, 12 Nov 2021)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    M llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-sdiv.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-srem.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-udiv.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/legalize-urem.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/sdiv.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/sdivrem.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/srem.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/udiv.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/udivrem.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/urem.i64.ll
    M llvm/test/CodeGen/AMDGPU/amdgpu-codegenprepare-idiv.ll
    M llvm/test/CodeGen/AMDGPU/bypass-div.ll
    M llvm/test/CodeGen/AMDGPU/carryout-selection.ll
    M llvm/test/CodeGen/AMDGPU/sdiv64.ll
    M llvm/test/CodeGen/AMDGPU/srem64.ll
    M llvm/test/CodeGen/AMDGPU/udiv64.ll
    M llvm/test/CodeGen/AMDGPU/urem64.ll
    M llvm/test/CodeGen/AMDGPU/wave32.ll

  Log Message:
  -----------
  [AMDGPU] Simplify 64-bit division/remainder expansion

The old expansion open-coded a 64-bit addition in a strange way, by
adding the high parts *without* carry-in from the low part, and then
adding the carry back in later on. Fixing this saves a couple of
instructions and makes the code much easier to understand.

Differential Revision: https://reviews.llvm.org/D113679