From df32aac51b611633301e4a2eb5824c9afa7bd674 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 14 Aug 2006 21:38:05 +0000 Subject: [PATCH] Handle single-entry PHI nodes correctly. This fixes PR877 and Transforms/CondProp/2006-08-14-SingleEntryPhiCrash.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29673 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/CondPropagate.cpp | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/lib/Transforms/Scalar/CondPropagate.cpp b/lib/Transforms/Scalar/CondPropagate.cpp index 101acef6dcb..49c87fd02f0 100644 --- a/lib/Transforms/Scalar/CondPropagate.cpp +++ b/lib/Transforms/Scalar/CondPropagate.cpp @@ -87,8 +87,18 @@ void CondProp::SimplifyBlock(BasicBlock *BB) { // If this block ends with an unconditional branch and the only successor has // only this block as a predecessor, merge the two blocks together. if (BranchInst *BI = dyn_cast(BB->getTerminator())) - if (BI->isUnconditional() && BI->getSuccessor(0)->getSinglePredecessor()) { + if (BI->isUnconditional() && BI->getSuccessor(0)->getSinglePredecessor() && + BB != BI->getSuccessor(0)) { BasicBlock *Succ = BI->getSuccessor(0); + + // If Succ has any PHI nodes, they are all single-entry PHI's. + while (PHINode *PN = dyn_cast(Succ->begin())) { + assert(PN->getNumIncomingValues() == 1 && + "PHI doesn't match parent block"); + PN->replaceAllUsesWith(PN->getIncomingValue(0)); + PN->eraseFromParent(); + } + // Remove BI. BI->eraseFromParent(); -- 2.34.1