[PATCH] D37902: [CodeExtractor] Fix multiple bugs under certain shape of extracted region

[Min-Yih Hsu via Phabricator via llvm-commits]

myhsu created this revision.
Herald added a subscriber: mgorny.

This revision consist of two part: exitStub bug and DomTree update problem
For the exitStub bug. If the extracted region has multiple exported data flows toward the same BB which is not included in the region, correct resotre instructions and PHI nodes won't be generated inside the exitStub. The solution is simply put the restore instructions right after the definition of output values instead of putting in exitStub.
Unittest for this bug is included

For the DomTree update problem. Currently it use GenericDominatorTree::splitBlock(GenericDominatorTree::Split underlying) to update DomTree. However, the API has several restrictions such as the NewBB can only has one successor and need to have predecessor, which is not generic enough and fails in some cases, like the first BB in the extracted region is the entry block. For the sake of not adding extra conditions for candidates of extracted region, my solution is updating the DomTree manually.


https://reviews.llvm.org/D37902

Files:
  lib/Transforms/Utils/CodeExtractor.cpp
  unittests/Transforms/Utils/CMakeLists.txt
  unittests/Transforms/Utils/CodeExtractor.cpp

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