[PATCH] D70318: Recover debug intrinsics when killing duplicate or empty basic blocks

[Stephen Tozer via Phabricator via llvm-commits]

StephenTozer created this revision.
StephenTozer added reviewers: probinson, aprantl, vsk, markus, djtodoro.
StephenTozer added a project: debug-info.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

Fixes the bug: https://bugs.llvm.org/show_bug.cgi?id=39339

When basic blocks are killed, either due to being empty or to being an if.then or if.else block whose complement contains identical instructions, the debug intrinsics in that block are lost. This fix attempts to recover those intrinsics by either hoisting or sinking them if possible, or replacing them in the above block with Undef values to prevent debug info from falling out-of-date.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D70318

Files:
  llvm/include/llvm/IR/DebugInfoMetadata.h
  llvm/lib/CodeGen/LiveDebugValues.cpp
  llvm/lib/IR/DebugInfoMetadata.cpp
  llvm/lib/Transforms/Utils/Local.cpp
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  llvm/test/Transforms/SimplifyCFG/hoist-dbgvalue-else.ll
  llvm/test/Transforms/SimplifyCFG/hoist-dbgvalue-empty.ll

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