[PATCH] D87494: Improve LSR debug-info

[Markus Lavin via Phabricator via llvm-commits]

markus updated this revision to Diff 308665.
markus added a reviewer: reames.
markus added a comment.

Addressing the issues with use of stored SCEV after IR had been deleted (see https://reviews.llvm.org/D91711).

The new approach is to, before rewrite, compute a set of SCEV equivalent values (with potential offset) and then store these values with a `WeakVH` to detect deletion.

After rewrite, for those `llvm.dbg.value` that now reference `undef` we pick one of the remaining equivalent values (if any).

So from a black-box point of view operation should be identical to before but now without abusing the SCEV API.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87494/new/

https://reviews.llvm.org/D87494

Files:
  llvm/include/llvm/Analysis/ScalarEvolution.h
  llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
  llvm/test/DebugInfo/COFF/fpo-shrink-wrap.ll
  llvm/test/Transforms/LoopStrengthReduce/dbg-preserve-0.ll

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