[all-commits] [llvm/llvm-project] 31c7a2: [FPEnv] Don't transform FSUB(-0, X)->FNEG(X) in Sel...

[Cameron McInally via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 31c7a2fd5c9a5b980768bd06354517d99ac8fe87
      https://github.com/llvm/llvm-project/commit/31c7a2fd5c9a5b980768bd06354517d99ac8fe87
  Author: Cameron McInally <mcinally at cray.com>
  Date:   2020-08-03 (Mon, 03 Aug 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
    M llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
    M llvm/test/CodeGen/AMDGPU/fcanonicalize-elimination.ll
    M llvm/test/CodeGen/AMDGPU/fcanonicalize.f16.ll
    M llvm/test/CodeGen/AMDGPU/fcanonicalize.ll
    M llvm/test/CodeGen/AMDGPU/fdiv32-to-rcp-folding.ll
    M llvm/test/CodeGen/AMDGPU/fmuladd.f16.ll
    M llvm/test/CodeGen/AMDGPU/fmuladd.f32.ll
    M llvm/test/CodeGen/AMDGPU/fneg-combines.ll
    M llvm/test/CodeGen/AMDGPU/selectcc-opt.ll
    M llvm/test/CodeGen/AMDGPU/set-dx10.ll

  Log Message:
  -----------
  [FPEnv] Don't transform FSUB(-0,X)->FNEG(X) in SelectionDAGBuilder.

This patch stops unconditionally transforming FSUB(-0,X) into an FNEG(X) while building the DAG. There is also one small change to handle the new FSUB(-0,X) similarly to FNEG(X) in the AMDGPU backend.

Differential Revision: https://reviews.llvm.org/D84056