[all-commits] [llvm/llvm-project] 1c4210: [RDA] Fix getUniqueReachingDef for self loops

[Sam Parker via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1c421046d742102e7016567d41a9db6a1fb61906
      https://github.com/llvm/llvm-project/commit/1c421046d742102e7016567d41a9db6a1fb61906
  Author: Sam Parker <sam.parker at arm.com>
  Date:   2020-09-16 (Wed, 16 Sep 2020)

  Changed paths:
    M llvm/lib/CodeGen/ReachingDefAnalysis.cpp
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/vctp-add-operand-liveout.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/wlstp.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/wrong-vctp-opcode-liveout.mir
    M llvm/test/CodeGen/Thumb2/LowOverheadLoops/wrong-vctp-operand-liveout.mir

  Log Message:
  -----------
  [RDA] Fix getUniqueReachingDef for self loops

We've fixed the case where this could return an instruction after the
given instruction, but also means that we can falsely return a
'unique' def when they could be one coming from the backedge of a
loop.

Differential Revision: https://reviews.llvm.org/D87751