[all-commits] [llvm/llvm-project] b66553: [Peephole] rewrite INSERT_SUBREG to SUBREG_TO_REG ...

[Allen via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b6655333c25556d2d9e3a9d73f488d525176d71c
      https://github.com/llvm/llvm-project/commit/b6655333c25556d2d9e3a9d73f488d525176d71c
  Author: zhongyunde <zhongyunde at huawei.com>
  Date:   2022-09-09 (Fri, 09 Sep 2022)

  Changed paths:
    M llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
    A llvm/test/CodeGen/AArch64/peephole-insert-subreg.mir

  Log Message:
  -----------
  [Peephole] rewrite INSERT_SUBREG to SUBREG_TO_REG if upper bits zero

Restrict the 32-bit form of an instruction of integer as too many test cases
will be clobber as the register number updated.
    From %reg = INSERT_SUBREG %reg, %subreg, subidx
    To   %reg:subidx =  SUBREG_TO_REG 0, %subreg, subidx
Try to prefix the redundant mov instruction at D132325 as the SUBREG_TO_REG should not generate code.

Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D132939