[all-commits] [llvm/llvm-project] 1011d4: [ARM] Constrain CMPZ shift combine to a single use

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1011d4ed60d9d32d53e20cbe72e47c9eecb84f49
      https://github.com/llvm/llvm-project/commit/1011d4ed60d9d32d53e20cbe72e47c9eecb84f49
  Author: David Green <david.green at arm.com>
  Date:   2021-05-13 (Thu, 13 May 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
    M llvm/lib/Target/ARM/ARMInstrThumb2.td
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/while-loops.ll
    M llvm/test/CodeGen/Thumb2/mve-float32regloops.ll
    M llvm/test/CodeGen/Thumb2/mve-postinc-lsr.ll
    M llvm/test/CodeGen/Thumb2/mve-vldst4.ll

  Log Message:
  -----------
  [ARM] Constrain CMPZ shift combine to a single use

We currently prefer t2CMPrs over t2CMPri when the node contains a shift.
This can introduce more nodes if the shift has multiple uses though, as
value from the shift will be needed anyway, and in the case of a t2CMPri
compared with zero will more readily be removed entirely.

Differential Revision: https://reviews.llvm.org/D101688