[llvm] [MemProf] Fix assert when exists direct recursion (PR #78264)

[via llvm-commits]

================
@@ -3472,15 +3472,19 @@ bool MemProfContextDisambiguation::applyImport(Module &M) {
             assert(StackMDNode);
             SmallVector<unsigned> StackIdsFromMetadata;
             CallStack<MDNode, MDNode::op_iterator> StackContext(StackMDNode);
-            for (auto ContextIter =
-                     StackContext.beginAfterSharedPrefix(CallsiteContext);
+            auto ContextIterBegin =
+                StackContext.beginAfterSharedPrefix(CallsiteContext);
+            uint64_t LastStackContextId = *ContextIterBegin == UINT64_MAX
----------------
lifengxiang1025 wrote:

I want to make sure the LastStackContextId is different with *ContextIterBegin and its values is between UINT64_MIN and UINT64_MAX.

https://github.com/llvm/llvm-project/pull/78264