[PATCH] D31032: [LoadCombine] Avoid analysing dead basic blocks

[Kenneth Hilmersson via Phabricator via llvm-commits]

KennethH created this revision.
Herald added subscribers: mzolotukhin, jholewinski.

Added an IsAlive flag to BasicBlockPass::runOnBasicBlock
which tells if the BB is alive or dead.
Dead basic blocks may be forming a loop, for which SSA form is
fulfilled, but with a circular def-use chain. LoadCombine could
enter an infinite loop when analysing such dead code. This patch
solves the problem by simply avoiding to analyse dead basic blocks
in LoadCombine.


https://reviews.llvm.org/D31032

Files:
  include/llvm/Pass.h
  lib/IR/IRPrintingPasses.cpp
  lib/IR/LegacyPassManager.cpp
  lib/Target/NVPTX/NVPTXLowerAlloca.cpp
  lib/Transforms/Scalar/DCE.cpp
  lib/Transforms/Scalar/LoadCombine.cpp
  lib/Transforms/Vectorize/BBVectorize.cpp
  test/Transforms/LoadCombine/deadcode.ll
  tools/bugpoint-passes/TestPasses.cpp
  tools/opt/PassPrinters.cpp
  unittests/IR/LegacyPassManagerTest.cpp

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