[all-commits] [llvm/llvm-project] 1b2fe7: [DAGCombiner] Tighten reasscociation of visitFMA

[Qiu Chaofan via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1b2fe71ecf6bd647a244fc64c231e31dfe1faaa2
      https://github.com/llvm/llvm-project/commit/1b2fe71ecf6bd647a244fc64c231e31dfe1faaa2
  Author: Qiu Chaofan <qiucofan at cn.ibm.com>
  Date:   2020-10-20 (Tue, 20 Oct 2020)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/test/CodeGen/PowerPC/fma-combine.ll
    M llvm/test/CodeGen/X86/fma-scalar-combine.ll

  Log Message:
  -----------
  [DAGCombiner] Tighten reasscociation of visitFMA

>From LangRef, FMF contract should not enable reassociating to form
arbitrary contractions. So it should not help rearrange nodes like
(fma (fmul x, c1), c2, y) into (fma x, c1*c2, y).

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D89527