Bug fix: X.mergeWith(Y) was not updating Y if Y was a null node handle!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10953 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DataStructure/DataStructure.cpp b/lib/Analysis/DataStructure/DataStructure.cpp
index caabff8..043579c 100644
--- a/lib/Analysis/DataStructure/DataStructure.cpp
+++ b/lib/Analysis/DataStructure/DataStructure.cpp
@@ -679,13 +679,20 @@
// Offset indicates what offset the specified node is to be merged into the
// current node.
//
-// The specified node may be a null pointer (in which case, nothing happens).
+// The specified node may be a null pointer (in which case, we update it to
+// point to this node).
//
void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
DSNode *N = NH.getNode();
- if (N == 0 || (N == this && NH.getOffset() == Offset))
+ if (N == this && NH.getOffset() == Offset)
return; // Noop
+ // If the RHS is a null node, make it point to this node!
+ if (N == 0) {
+ NH.mergeWith(DSNodeHandle(this, Offset));
+ return;
+ }
+
assert(!N->isDeadNode() && !isDeadNode());
assert(!hasNoReferrers() && "Should not try to fold a useless node!");