[PATCH] D81089: Mark InstCombine as not preserving PostDomTree

[Yevgeny Rouban via Phabricator via llvm-commits]

yrouban created this revision.
yrouban added reviewers: dberlin, brzycki, mkazantsev, ebrevnov, asbirlea, spatel, nikic.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.

A fix for the bug 46098 <https://bugs.llvm.org/show_bug.cgi?id=46098> "PostDominatorTree is different than a freshly computed one!" with opt -branch-prob -instcombine -block-freq -verify-dom-info

InstCombine invalidates PostDomTree.
See the example in the new test llvm/test/Transforms/InstCombine/infinite-loop-postdom.ll
A better fix would be to improve PostDomTree to be insensitive to the order of successors in post-dom unreachable subgraphs.


https://reviews.llvm.org/D81089

Files:
  llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
  llvm/test/Other/opt-O2-pipeline.ll
  llvm/test/Other/opt-O3-pipeline.ll
  llvm/test/Other/opt-Os-pipeline.ll
  llvm/test/Other/optimization-remarks-invalidation.ll
  llvm/test/Transforms/InstCombine/infinite-loop-postdom.ll

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