[llvm] [MemProf] Prune unneeded non-cold contexts (PR #124823)

[Teresa Johnson via llvm-commits]

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@@ -337,10 +371,16 @@ bool CallStackTrie::buildAndAttachMIBMetadata(CallBase *CI) {
   MIBCallStack.push_back(AllocStackId);
   std::vector<Metadata *> MIBNodes;
   assert(!Alloc->Callers.empty() && "addCallStack has not been called yet");
-  // The last parameter is meant to say whether the callee of the given node
-  // has more than one caller. Here the node being passed in is the alloc
-  // and it has no callees. So it's false.
-  if (buildMIBNodes(Alloc, Ctx, MIBCallStack, MIBNodes, false)) {
+  // The CalleeHasAmbiguousCallerContext flag is meant to say whether the
+  // callee of the given node has more than one caller. Here the node being
+  // passed in is the alloc and it has no callees. So it's false.
+  // Similarly, the last parameter is meant to say whether the callee of the
+  // given node is the deepest point where we have ambiguous alloc types, which
+  // is also false as the alloc has no callees.
+  bool DeepestAmbiguousAllocType = true;
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teresajohnson wrote:

I started to do this but it made the uses more complicated inside buildMIBNodes and I think it ends up more complicated and hard to reason about overall. So I'd prefer to leave as-is.

https://github.com/llvm/llvm-project/pull/124823