[PATCH] D115985: Remove unreachable blocks after jumpthreading

[Duanyang Jing via Phabricator via llvm-commits]

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In the jumpthreading main loop in runImpl, we handle unreachable blocks generated in the middle of transformation by checking pred_empty(&BB), and delete this block. But this mechanism seems insufficient: when a BB is made unreachable, it may still have a predecessor.  This is true when the bb is part of a connected component and the edge from entry block to the component is removed.

This patch adds a full clean-up of unreachable blocks after the transformation.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115985

Files:
  llvm/lib/Transforms/Scalar/JumpThreading.cpp
  llvm/test/Transforms/JumpThreading/SimplifyUnreachableBlock.ll

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