[all-commits] [llvm/llvm-project] 822059: [PowerPC] [Peephole] fold frame offset by using in...

[chen zheng via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 822059147bf2870d88321824d41c92abb1f671d1
      https://github.com/llvm/llvm-project/commit/822059147bf2870d88321824d41c92abb1f671d1
  Author: czhengsz <czhengsz at cn.ibm.com>
  Date:   2019-10-25 (Fri, 25 Oct 2019)

  Changed paths:
    M llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
    M llvm/lib/Target/PowerPC/PPCInstrInfo.h
    M llvm/lib/Target/PowerPC/PPCPreEmitPeephole.cpp
    M llvm/lib/Target/PowerPC/PPCRegisterInfo.h
    M llvm/test/CodeGen/PowerPC/fold-frame-offset-using-rr.mir

  Log Message:
  -----------
  [PowerPC] [Peephole] fold frame offset by using index form to save add.

renamable $x6 = ADDI8 $x1, -80      ;;; 0 is replaced with -80
renamable $x6 = ADD8 killed renamable $x6, renamable $x5
STW killed renamable $r3, 4, killed renamable $x6 :: (store 4 into %ir.14, !tbaa !2)

After PEI there is a peephole opt opportunity to combine above -80 in ADDI8 with 4 in the STW to eliminate unnecessary ADD8.

Expected result:
renamable $x6 = ADDI8 $x1, -76
STWX killed renamable $r3, renamable $x5, killed renamable $x6 :: (store 4 into %ir.6, !tbaa !2)

Reviewed by: stefanp

Differential Revision: https://reviews.llvm.org/D66329