[all-commits] [llvm/llvm-project] f2334a: [AMDGPU] Fix crash in SILoadStoreOptimizer

[Stanislav Mekhanoshin via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f2334a7ef255ffe906d864d7ba078aba54646abb
      https://github.com/llvm/llvm-project/commit/f2334a7ef255ffe906d864d7ba078aba54646abb
  Author: Stanislav Mekhanoshin <Stanislav.Mekhanoshin at amd.com>
  Date:   2020-04-02 (Thu, 02 Apr 2020)

  Changed paths:
    M llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp
    A llvm/test/CodeGen/AMDGPU/merge-out-of-order-ldst.ll
    A llvm/test/CodeGen/AMDGPU/merge-out-of-order-ldst.mir

  Log Message:
  -----------
  [AMDGPU] Fix crash in SILoadStoreOptimizer

SILoadStoreOptimizer::checkAndPrepareMerge() expects base and
paired instruction to come in order and scans MBB from base to
the paired instruction. An original order can be changed if
there were a dependent instruction in between and base instruction
was moved.

Fixed by bailing the optimization. In theory it might be possible
still to perform a merge by swapping instructions, but on practice
it bails anyway because it finds dependency on that same instruction
which has resulted in the base move.

Differential Revision: https://reviews.llvm.org/D77245