[PATCH] D75173: [Transform][MemCpyOpt] Add missing DebugLoc to %tmpbitcast

[Vedant Kumar via Phabricator via llvm-commits]

vsk added a comment.

@Pierre-vh you can run `opt` with `-debug-pass=Structure` to see what it's doing. In this case, it's stripping out all the debug metadata right before printing module IR:

  ModulePass Manager
    FunctionPass Manager
      [snip ...]
      Attach debug info to a function
      Phi Values Analysis
      Memory Dependence Analysis
      MemCpy Optimization
      Check debug info from -debugify-function
      Attach debug info to a function
      Module Verifier
      Check debug info from -debugify-function
    Print Module IR

So that's why the 'CHECK' line doesn't match !dbg, it got stripped out. If you change your RUN line to do `opt -instcombine -debugify -memcpyopt -check-debugify`, opt will produce IR you can write a positive test against.

As for reducing the test, you can try to find a simpler way to trigger this code path in MemCpyOpt. llvm/test/Transforms/MemCpyOpt/memcpy.ll has lots of tidy examples, perhaps running one of those examples through -debugify-each would hit the same bug.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D75173/new/

https://reviews.llvm.org/D75173