[all-commits] [llvm/llvm-project] 97203c: [GISel] Add new GISel combiners for G_MUL

[proaditya via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 97203cfd6bae0388f9dd22ddca592737324a2c72
      https://github.com/llvm/llvm-project/commit/97203cfd6bae0388f9dd22ddca592737324a2c72
  Author: Aditya Nandakumar <aditya_nandakumar at apple.com>
  Date:   2020-09-15 (Tue, 15 Sep 2020)

  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
    A llvm/test/CodeGen/AArch64/GlobalISel/combine-mul.mir

  Log Message:
  -----------
  [GISel] Add new GISel combiners for G_MUL

https://reviews.llvm.org/D87668

Patch adds two new GICombinerRules, one for G_MUL(X, 1) and another for G_MUL(X, -1).
G_MUL(X, 1) is an identity combine, and G_MUL(X, -1) gets replaced with G_SUB(0, X).
Patch additionally adds new combiner tests for the AArch64 target to test these
new combiner rules, as well as updates AMDGPU GISel tests.

Patch by mkitzan