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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137175 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
NAKAMURA Takumi 2011-08-09 23:13:05 +00:00
parent 8fc9b3db53
commit 77c714027c

View File

@ -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<PHINode>(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<PHINode>(II);
if (!PN)
break;
int i;
while ((i = PN->getBasicBlockIndex(this)) >= 0)
PN->setIncomingBlock(i, New);