[all-commits] [llvm/llvm-project] 31f02a: [ARM] Use mov operand if the mov cannot be moved w...

[Sam Tebbs via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 31f02ac60aa8e89c04617e82fa2b1140e33e824d
      https://github.com/llvm/llvm-project/commit/31f02ac60aa8e89c04617e82fa2b1140e33e824d
  Author: Sam Tebbs <samuel.tebbs at arm.com>
  Date:   2020-08-18 (Tue, 18 Aug 2020)

  Changed paths:
    M llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
    A llvm/test/CodeGen/Thumb2/LowOverheadLoops/mov-after-dlstp.mir
    A llvm/test/CodeGen/Thumb2/LowOverheadLoops/mov-operand.ll

  Log Message:
  -----------
  [ARM] Use mov operand if the mov cannot be moved while tail predicating

There are some cases where the instruction that sets up the iteration
count for a tail predicated loop cannot be moved before the dlstp,
stopping tail predication entirely. This patch checks if the mov operand
can be used and if so, uses that instead.

Differential Revision: https://reviews.llvm.org/D86087