improve comments, add an assertion
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33750 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
index 1d04abf..1b0e81e 100644
--- a/lib/Support/FoldingSet.cpp
+++ b/lib/Support/FoldingSet.cpp
@@ -226,6 +226,7 @@
/// is not already in the map. InsertPos must be obtained from
/// FindNodeOrInsertPos.
void FoldingSetImpl::InsertNode(Node *N, void *InsertPos) {
+ assert(N->getNextInBucket() == 0);
// Do we need to grow the hashtable?
DEBUG(DOUT << "INSERT: " << N << '\n');
if (NumNodes+1 > NumBuckets*2) {
@@ -256,16 +257,18 @@
/// removed or false if the node was not in the folding set.
bool FoldingSetImpl::RemoveNode(Node *N) {
// Because each bucket is a circular list, we don't need to compute N's hash
- // to remove it. Chase around the list until we find the node (or bucket)
- // which points to N.
+ // to remove it.
DEBUG(DOUT << "REMOVE: " << N << '\n');
void *Ptr = N->getNextInBucket();
if (Ptr == 0) return false; // Not in folding set.
--NumNodes;
-
- void *NodeNextPtr = Ptr;
N->SetNextInBucket(0);
+
+ // Remember what N originally pointed to, either a bucket or another node.
+ void *NodeNextPtr = Ptr;
+
+ // Chase around the list until we find the node (or bucket) which points to N.
while (true) {
if (Node *NodeInBucket = GetNextPtr(Ptr, Buckets, NumBuckets)) {
// Advance pointer.