[all-commits] [llvm/llvm-project] 9d9a11: [ARM] Check for LSTP side-effects.

[Sam Parker via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 9d9a11c7be037cbbfb5239b72dbeb48dd2601bbc
      https://github.com/llvm/llvm-project/commit/9d9a11c7be037cbbfb5239b72dbeb48dd2601bbc
  Author: Sam Parker <sam.parker at arm.com>
  Date:   2020-09-24 (Thu, 24 Sep 2020)

  Changed paths:
    M llvm/lib/Target/ARM/ARMLowOverheadLoops.cpp
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/iv-two-vcmp.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/lstp-insertion-position.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/mov-after-dlstp.mir
    M llvm/test/CodeGen/Thumb2/mve-gather-scatter-tailpred.ll

  Log Message:
  -----------
  [ARM] Check for LSTP side-effects.

If the LSTP instruction is inserted with an element count low enough
to immediately predicate some lanes as false, this can have some
unintended effects on any proceeding MVE instructions in the
preheader.

Differential Revision: https://reviews.llvm.org/D88209