From 36c4debc94e7c68c769dfda781851a0c963dd746 Mon Sep 17 00:00:00 2001 From: Owen Anderson Date: Wed, 29 Sep 2010 20:34:41 +0000 Subject: Fix PR8247: JumpThreading can cause a block to become unreachable while still having predecessor, if it is part of a self-loop. Because of this, we cannot use the Simplify* APIs, as they can assert-fail on unreachable code. Since it's not easy to determine if a given threading will cause a block to become unreachable, simply defer simplifying simplification to later InstCombine and/or DCE passes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115082 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/JumpThreading.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'lib/Transforms/Scalar/JumpThreading.cpp') diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index ce99afb1b6..43460beb3b 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -613,7 +613,7 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) { TerminatorInst *BBTerm = BB->getTerminator(); for (unsigned i = 0, e = BBTerm->getNumSuccessors(); i != e; ++i) { if (i == BestSucc) continue; - RemovePredecessorAndSimplify(BBTerm->getSuccessor(i), BB, TD); + BBTerm->getSuccessor(i)->removePredecessor(BB, true); } DEBUG(dbgs() << " In block '" << BB->getName() @@ -664,7 +664,7 @@ bool JumpThreading::ProcessBlock(BasicBlock *BB) { if (PI == PE) { unsigned ToRemove = Baseline == LazyValueInfo::True ? 1 : 0; unsigned ToKeep = Baseline == LazyValueInfo::True ? 0 : 1; - RemovePredecessorAndSimplify(CondBr->getSuccessor(ToRemove), BB, TD); + CondBr->getSuccessor(ToRemove)->removePredecessor(BB, true); BranchInst::Create(CondBr->getSuccessor(ToKeep), CondBr); CondBr->eraseFromParent(); return true; @@ -1470,7 +1470,7 @@ bool JumpThreading::ThreadEdge(BasicBlock *BB, TerminatorInst *PredTerm = PredBB->getTerminator(); for (unsigned i = 0, e = PredTerm->getNumSuccessors(); i != e; ++i) if (PredTerm->getSuccessor(i) == BB) { - RemovePredecessorAndSimplify(BB, PredBB, TD); + BB->removePredecessor(PredBB, true); PredTerm->setSuccessor(i, NewBB); } @@ -1620,7 +1620,7 @@ bool JumpThreading::DuplicateCondBranchOnPHIIntoPred(BasicBlock *BB, // PredBB no longer jumps to BB, remove entries in the PHI node for the edge // that we nuked. - RemovePredecessorAndSimplify(BB, PredBB, TD); + BB->removePredecessor(PredBB, true); // Remove the unconditional branch at the end of the PredBB block. OldPredBranch->eraseFromParent(); -- cgit v1.2.3