[all-commits] [llvm/llvm-project] fd6f8b: [AMDGPU] [GlobalIsel] Combine Fmul with Select int...

[Vikash Gupta via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: fd6f8b3ce33cc2cbe378f8f1b391f3f40fa7bd54
      https://github.com/llvm/llvm-project/commit/fd6f8b3ce33cc2cbe378f8f1b391f3f40fa7bd54
  Author: Vikash Gupta <Vikash.Gupta at amd.com>
  Date:   2025-01-06 (Mon, 06 Jan 2025)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPUCombine.td
    M llvm/lib/Target/AMDGPU/AMDGPUCombinerHelper.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUCombinerHelper.h
    M llvm/lib/Target/AMDGPU/AMDGPUPostLegalizerCombiner.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUPreLegalizerCombiner.cpp
    M llvm/test/CodeGen/AMDGPU/GlobalISel/fpow.ll
    M llvm/test/CodeGen/AMDGPU/GlobalISel/llvm.powi.ll
    M llvm/test/CodeGen/AMDGPU/dagcombine-fmul-sel.ll
    M llvm/test/CodeGen/AMDGPU/fdiv_flags.f32.ll
    M llvm/test/CodeGen/AMDGPU/fmul-to-ldexp.ll
    M llvm/test/CodeGen/AMDGPU/fsqrt.f32.ll
    M llvm/test/CodeGen/AMDGPU/llvm.exp2.ll
    M llvm/test/CodeGen/AMDGPU/llvm.log.ll
    M llvm/test/CodeGen/AMDGPU/llvm.log10.ll
    M llvm/test/CodeGen/AMDGPU/llvm.log2.ll
    M llvm/test/CodeGen/AMDGPU/pseudo-scalar-transcendental.ll

  Log Message:
  -----------
  [AMDGPU] [GlobalIsel] Combine Fmul with Select into ldexp instruction. (#120104)

This combine pattern perform the below transformation.

fmul x, select(y, A, B)      -> fldexp (x, select i32 (y, a, b))
fmul x, select(y, -A, -B)   -> fldexp ((fneg x), select i32 (y, a, b))

where, A=2^a & B=2^b ; a and b are integers.

It is a follow-up PR to implement the above combine for globalIsel, as
the corresponding DAG combine has been done for SelectionDAG Isel
(#111109)



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