Fix Value::stripPointerCasts and BasicAA to avoid trouble on
code in unreachable blocks, which have have use-def cycles.
This fixes PR7514.
llvm-svn: 107071
diff --git a/llvm/lib/VMCore/Value.cpp b/llvm/lib/VMCore/Value.cpp
index 645dd5a..585edf0 100644
--- a/llvm/lib/VMCore/Value.cpp
+++ b/llvm/lib/VMCore/Value.cpp
@@ -322,7 +322,13 @@
Value *Value::stripPointerCasts() {
if (!getType()->isPointerTy())
return this;
+
+ // Even though we don't look through PHI nodes, we could be called on an
+ // instruction in an unreachable block, which may be on a cycle.
+ SmallPtrSet<Value *, 4> Visited;
+
Value *V = this;
+ Visited.insert(V);
do {
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
if (!GEP->hasAllZeroIndices())
@@ -338,7 +344,9 @@
return V;
}
assert(V->getType()->isPointerTy() && "Unexpected operand type!");
- } while (1);
+ } while (Visited.insert(V));
+
+ return V;
}
Value *Value::getUnderlyingObject(unsigned MaxLookup) {