[all-commits] [llvm/llvm-project] db464a: [GISel] Add new GISel combiners for G_SELECT

[proaditya via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: db464a3dbf0e8fed363a7b2b9a5b320514ca60f8
      https://github.com/llvm/llvm-project/commit/db464a3dbf0e8fed363a7b2b9a5b320514ca60f8
  Author: Aditya Nandakumar <aditya_nandakumar at apple.com>
  Date:   2020-08-27 (Thu, 27 Aug 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-select.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/postlegalizercombiner-select.mir

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

https://reviews.llvm.org/D83833

Patch adds two new GICombinerRules for G_SELECT. The rules include:
combining selects with undef comparisons into their first selectee value,
and to combine away selects with constant comparisons. Patch additionally
adds a new combiner test for the AArch64 target to test these new G_SELECT
combiner rules and the existing select_same_val combiner rule.

Patch by  mkitzan