[all-commits] [llvm/llvm-project] d7e03d: [AMDGPU] Implement widening multiplies with v_mad_...

[Jay Foad via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: d7e03df719464354b20a845b7853be57da863924
      https://github.com/llvm/llvm-project/commit/d7e03df719464354b20a845b7853be57da863924
  Author: Jay Foad <jay.foad at amd.com>
  Date:   2021-11-24 (Wed, 24 Nov 2021)

  Changed paths:
    M llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.h
    M llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    M llvm/lib/Target/AMDGPU/AMDGPUISelLowering.h
    M llvm/lib/Target/AMDGPU/SIISelLowering.cpp
    M llvm/lib/Target/AMDGPU/SIISelLowering.h
    M llvm/test/CodeGen/AMDGPU/atomic_optimizations_global_pointer.ll
    M llvm/test/CodeGen/AMDGPU/atomic_optimizations_local_pointer.ll
    M llvm/test/CodeGen/AMDGPU/bypass-div.ll
    M llvm/test/CodeGen/AMDGPU/llvm.mulo.ll
    M llvm/test/CodeGen/AMDGPU/mad_64_32.ll
    M llvm/test/CodeGen/AMDGPU/mul.ll
    M llvm/test/CodeGen/AMDGPU/mul_int24.ll
    M llvm/test/CodeGen/AMDGPU/mul_uint24-amdgcn.ll
    M llvm/test/CodeGen/AMDGPU/udiv.ll
    M llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll
    M llvm/test/CodeGen/AMDGPU/wwm-reserved.ll

  Log Message:
  -----------
  [AMDGPU] Implement widening multiplies with v_mad_i64_i32/v_mad_u64_u32

Select SelectionDAG ops smul_lohi/umul_lohi to
v_mad_i64_i32/v_mad_u64_u32 respectively, with an addend of 0.
v_mul_lo, v_mul_hi and v_mad_i64/u64 are all quarter-rate instructions
so it is better to use one instruction than two.

Further improvements are possible to make better use of the addend
operand, but this is already a strict improvement over what we have
now.

Differential Revision: https://reviews.llvm.org/D113986