[MemProf] Strip callsite metadata when inlining an unprofiled callsite (#110998)

We weren't flagging inlined callee functions with callsite but not
memprof metadata correctly, leading to the callsite metadata not being
stripped when that function was inlined into a callsite that didn't
itself have callsite metadata.

In practice, this meant that we went into the LTO link with many more
calls than necessary having callsite metadata / summary records, which
in turn made the graph larger than necessary.

Fixing this oversight resulted in huge reductions in the thin link of a
large target:
99% fewer duplicated context ids (recall we have to duplicate when
callsites containing the same stack ids are in different functions)
71% fewer graph edges
17% fewer graph nodes
13% fewer functions cloned
44% smaller peak memory
47% smaller time

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index dc9ca14..fc03643 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -70,6 +70,7 @@ BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
     if (isa<CallInst>(I) && !I.isDebugOrPseudoInst()) {
       hasCalls = true;
       hasMemProfMetadata |= I.hasMetadata(LLVMContext::MD_memprof);
+      hasMemProfMetadata |= I.hasMetadata(LLVMContext::MD_callsite);
     }
     if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I)) {
       if (!AI->isStaticAlloca()) {
@@ -556,6 +557,7 @@ void PruningFunctionCloner::CloneBlock(
     if (isa<CallInst>(II) && !II->isDebugOrPseudoInst()) {
       hasCalls = true;
       hasMemProfMetadata |= II->hasMetadata(LLVMContext::MD_memprof);
+      hasMemProfMetadata |= II->hasMetadata(LLVMContext::MD_callsite);
     }
 
     CloneDbgRecordsToHere(NewInst, II);