diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -1050,9 +1050,9 @@
                                       "no memprof data available in profile");
   auto Iter = MemProfRecordTable->find(FuncNameHash);
   if (Iter == MemProfRecordTable->end())
-    return make_error<InstrProfError>(instrprof_error::hash_mismatch,
-                                      "memprof record not found for hash " +
-                                          Twine(FuncNameHash));
+    return make_error<InstrProfError>(
+        instrprof_error::unknown_function,
+        "memprof record not found for function hash " + Twine(FuncNameHash));
 
   // Setup a callback to convert from frame ids to frame using the on-disk
   // FrameData hash table.
diff --git a/llvm/unittests/ProfileData/InstrProfTest.cpp b/llvm/unittests/ProfileData/InstrProfTest.cpp
--- a/llvm/unittests/ProfileData/InstrProfTest.cpp
+++ b/llvm/unittests/ProfileData/InstrProfTest.cpp
@@ -352,8 +352,15 @@
   auto Profile = Writer.writeBuffer();
   readProfile(std::move(Profile));
 
+  // Missing frames give a hash_mismatch error.
   auto RecordOr = Reader->getMemProfRecord(0x9999);
-  EXPECT_THAT_ERROR(RecordOr.takeError(), Failed());
+  ASSERT_TRUE(
+      ErrorEquals(instrprof_error::hash_mismatch, RecordOr.takeError()));
+
+  // Missing functions give a unknown_function error.
+  RecordOr = Reader->getMemProfRecord(0x1111);
+  ASSERT_TRUE(
+      ErrorEquals(instrprof_error::unknown_function, RecordOr.takeError()));
 }
 
 TEST_F(InstrProfTest, test_memprof_merge) {