[all-commits] [llvm/llvm-project] 53125e: [DebugInfo] Handle joins PHI+Def values in InstrRe...

[Stephen Tozer via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 53125e7d916306582bee0c828d38d1ef6d6061dc
      https://github.com/llvm/llvm-project/commit/53125e7d916306582bee0c828d38d1ef6d6061dc
  Author: Stephen Tozer <stephen.tozer at sony.com>
  Date:   2022-08-22 (Mon, 22 Aug 2022)

  Changed paths:
    M llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
    A llvm/test/DebugInfo/MIR/X86/instr-ref-join-def-vphi.mir
    M llvm/unittests/CodeGen/InstrRefLDVTest.cpp

  Log Message:
  -----------
  [DebugInfo] Handle joins PHI+Def values in InstrRef LiveDebugValues

In the InstrRefBasedImpl for LiveDebugValues, we attempt to propagate
debug values through basic blocks in part by checking to see whether all
a variable's incoming debug values to a BB "agree", i.e. whether their
properties match and they refer to the same underlying value.

Prior to this patch, the check for agreement between incoming values
relied on exact equality, which meant that a VPHI and a Def DbgValue
that referred to the same underlying value would be seen as disagreeing.
This patch changes this behaviour to treat them as referring to the same
value, allowing the shared value to propagate into the BB.

Differential Revision: https://reviews.llvm.org/D125953