diff --git a/llvm/include/llvm/ProfileData/SampleProf.h b/llvm/include/llvm/ProfileData/SampleProf.h
--- a/llvm/include/llvm/ProfileData/SampleProf.h
+++ b/llvm/include/llvm/ProfileData/SampleProf.h
@@ -515,6 +515,8 @@
   sampleprof_error merge(const FunctionSamples &Other, uint64_t Weight = 1) {
     sampleprof_error Result = sampleprof_error::success;
     Name = Other.getName();
+    if (!GUIDToFuncNameMap)
+      GUIDToFuncNameMap = Other.GUIDToFuncNameMap;
     MergeResult(Result, addTotalSamples(Other.getTotalSamples(), Weight));
     MergeResult(Result, addHeadSamples(Other.getHeadSamples(), Weight));
     for (const auto &I : Other.getBodySamples()) {
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -1104,16 +1104,21 @@
     }
 
     if (ProfileMergeInlinee) {
-      // Use entry samples as head samples during the merge, as inlinees
-      // don't have head samples.
-      assert(FS->getHeadSamples() == 0 && "Expect 0 head sample for inlinee");
-      const_cast<FunctionSamples *>(FS)->addHeadSamples(FS->getEntrySamples());
-
-      // Note that we have to do the merge right after processing function.
-      // This allows OutlineFS's profile to be used for annotation during
-      // top-down processing of functions' annotation.
-      FunctionSamples *OutlineFS = Reader->getOrCreateSamplesFor(*Callee);
-      OutlineFS->merge(*FS);
+      if (FS->getHeadSamples() == 0) {
+        // Use entry samples as head samples during the merge, as inlinees
+        // don't have head samples.
+        const_cast<FunctionSamples *>(FS)->addHeadSamples(
+            FS->getEntrySamples());
+
+        // Note that we have to do the merge right after processing function.
+        // This allows OutlineFS's profile to be used for annotation during
+        // top-down processing of functions' annotation.
+        FunctionSamples *OutlineFS = Reader->getOrCreateSamplesFor(*Callee);
+        OutlineFS->merge(*FS);
+      } else
+        assert(FS->getHeadSamples() == FS->getEntrySamples() &&
+               "Expect same head and entry sample counts for profiles already "
+               "merged.");
     } else {
       auto pair =
           notInlinedCallInfo.try_emplace(Callee, NotInlinedProfileInfo{0});