[PATCH] D121310: [IROutliner] IR Outliner can mix up order of incoming values when compressing phi nodes if contain the same values

[Andrew Litteken via Phabricator via llvm-commits]

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Github issue: https://github.com/llvm/llvm-project/issues/54211

Example: https://godbolt.org/z/KrKPojnqE

When matching PHINodes when margining functions the IROutliner only checks that an incoming value exists in phi node in overall function. It doesn't check the length, the order, or that the incoming block also matches. In the given example, we see that both phi nodes have the same incoming values, but from different blocks.

The fix is to to enforce stricter a match of the incoming value, and the incoming block as well when matching the created phi nodes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D121310

Files:
  llvm/include/llvm/Transforms/IPO/IROutliner.h
  llvm/lib/Transforms/IPO/IROutliner.cpp
  llvm/test/Transforms/IROutliner/different-order-phi-merges.ll

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