[all-commits] [llvm/llvm-project] 8dda51: [DebugInfo][InstrRef] Avoid dropping fragment info...

[Jeremy Morse via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8dda516b83255f96b3918f73bb64282655c4cc75
      https://github.com/llvm/llvm-project/commit/8dda516b83255f96b3918f73bb64282655c4cc75
  Author: Jeremy Morse <jeremy.morse at sony.com>
  Date:   2021-11-30 (Tue, 30 Nov 2021)

  Changed paths:
    M llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
    M llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h
    A llvm/test/DebugInfo/MIR/InstrRef/out-of-scope-blocks.mir
    M llvm/unittests/CodeGen/InstrRefLDVTest.cpp

  Log Message:
  -----------
  [DebugInfo][InstrRef] Avoid dropping fragment info during PHI elimination

InstrRefBasedLDV used to crash on the added test -- the exit block is not
in scope for the variable being propagated, but is still considered because
it contains an assignment. The failure-mode was vlocJoin ignoring
assign-only blocks and not updating DIExpressions, but pickVPHILoc would
still find a variable location for it. That led to DBG_VALUEs created with
the wrong fragment information.

Fix this by removing a filter inherited from VarLocBasedLDV: vlocJoin will
now consider assign-only blocks and will update their expressions.

Differential Revision: https://reviews.llvm.org/D114727