[all-commits] [llvm/llvm-project] 892497: [GlobalISel] Simplify G_ICMP to true/false when th...

[Jessica Paquette via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 892497c806306a4b7185ead16d60b0ebcca0a304
      https://github.com/llvm/llvm-project/commit/892497c806306a4b7185ead16d60b0ebcca0a304
  Author: Jessica Paquette <jpaquette at apple.com>
  Date:   2021-05-18 (Tue, 18 May 2021)

  Changed paths:
    M llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
    M llvm/include/llvm/Target/GlobalISel/Combine.td
    M llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
    M llvm/lib/Target/AArch64/AArch64Combine.td
    A llvm/test/CodeGen/AArch64/GlobalISel/prelegalizer-combiner-icmp-to-true-false-known-bits.mir
    M llvm/test/CodeGen/AArch64/fold-global-offsets.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/cvt_f32_ubyte.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/fshl.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/fshr.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/saddsat.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/sdiv.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/srem.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/ssubsat.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/udiv.i64.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/urem.i64.ll

  Log Message:
  -----------
  [GlobalISel] Simplify G_ICMP to true/false when the result is known

Use existing KnownBits helpers from KnownBits.h to simplify G_ICMPs.

E.g.

x == x -> true
x != x -> false
load(x) > 1 -> true (when the load is known to be greater than 1)

And so on.

Differential Revision: https://reviews.llvm.org/D102542