Fix a subtle iterator invalidation bug in a recursive algorithm.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40776 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-08-03 11:03:26 +00:00
parent 1af002d362
commit 4b55c3b0f1

View File

@ -726,19 +726,21 @@ Value *GVN::GetValueForBlock(BasicBlock *BB, LoadInst* orig,
bool top_level) {
// If we have already computed this value, return the previously computed val.
Value *&V = Phis[BB];
Value *V = Phis[BB];
if (V && ! top_level) return V;
BasicBlock* singlePred = BB->getSinglePredecessor();
if (singlePred)
return V = GetValueForBlock(singlePred, orig, Phis);
if (singlePred) {
V = GetValueForBlock(singlePred, orig, Phis);
Phis[BB] = V;
return V;
}
// Otherwise, the idom is the loop, so we need to insert a PHI node. Do so
// now, then get values to fill in the incoming values for the PHI.
PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle",
BB->begin());
PN->reserveOperandSpace(std::distance(pred_begin(BB), pred_end(BB)));
V = PN;
Phis[BB] = PN;
bool all_same = true;
Value* first = 0;