[all-commits] [llvm/llvm-project] e1472d: [GlobalISel] Implement commuting shl (add/or x, c1...

[Amara Emerson via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e1472db58ef501264547ac8c97be2bf7c481ec04
      https://github.com/llvm/llvm-project/commit/e1472db58ef501264547ac8c97be2bf7c481ec04
  Author: Amara Emerson <amara at apple.com>
  Date:   2023-05-08 (Mon, 08 May 2023)

  Changed paths:
    M llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
    M llvm/include/llvm/CodeGen/TargetLowering.h
    M llvm/include/llvm/Target/GlobalISel/Combine.td
    M llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
    A llvm/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-commute-shift.mir
    M llvm/test/CodeGen/AMDGPU/GlobalISel/add_shl.ll

  Log Message:
  -----------
  [GlobalISel] Implement commuting shl (add/or x, c1), c2 -> add/or (shl x, c2), c1 << c2

There's a target hook that's called in DAGCombiner that we stub here, I'll
implement the equivalent override for AArch64 in a subsequent patch since it's
used by different shift combine.

This change by itself has minor code size improvements on arm64 -Os CTMark:
Program                                       size.__text
                                              outputg181ppyy output8av1cxfn diff
consumer-typeset/consumer-typeset             410648.00      410648.00       0.0%
tramp3d-v4/tramp3d-v4                         364176.00      364176.00       0.0%
kimwitu++/kc                                  449216.00      449212.00      -0.0%
7zip/7zip-benchmark                           576128.00      576120.00      -0.0%
sqlite3/sqlite3                               285108.00      285100.00      -0.0%
SPASS/SPASS                                   411720.00      411688.00      -0.0%
ClamAV/clamscan                               379868.00      379764.00      -0.0%
Bullet/bullet                                 452064.00      451928.00      -0.0%
mafft/pairlocalalign                          246184.00      246108.00      -0.0%
lencod/lencod                                 428524.00      428152.00      -0.1%
                           Geomean difference                               -0.0%

Differential Revision: https://reviews.llvm.org/D150086