From 604b5388205c4d80a45bd97283f35e6991a711dc Mon Sep 17 00:00:00 2001 From: NAKAMURA Takumi Date: Tue, 9 Aug 2011 23:13:05 +0000 Subject: [PATCH] VMCore/BasicBlock.cpp: Don't assume BasicBlock::iterator might end with a non-PHInode Instruction in successors. Frontends(eg. clang) might pass incomplete form of IR, to step off the way beyond iterator end. In the case I had met, it took infinite loop due to meeting bogus PHInode. Thanks to Jay Foad and John McCall. llvm-svn: 137175 --- lib/VMCore/BasicBlock.cpp | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp index df6d1f4ce4d..5fab1d39ae8 100644 --- a/lib/VMCore/BasicBlock.cpp +++ b/lib/VMCore/BasicBlock.cpp @@ -336,8 +336,12 @@ void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) { return; for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) { BasicBlock *Succ = TI->getSuccessor(i); - for (iterator II = Succ->begin(); PHINode *PN = dyn_cast(II); - ++II) { + // N.B. Succ might not be a complete BasicBlock, so don't assume + // that it ends with a non-phi instruction. + for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) { + PHINode *PN = dyn_cast(II); + if (!PN) + break; int i; while ((i = PN->getBasicBlockIndex(this)) >= 0) PN->setIncomingBlock(i, New);