diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -315,6 +315,27 @@
         StackIdIndices(std::move(StackIdIndices)) {}
 };
 
+inline raw_ostream &operator<<(raw_ostream &OS, const CallsiteInfo &SNI) {
+  OS << "Callee: " << SNI.Callee;
+  bool First = true;
+  OS << " Clones: ";
+  for (auto V : SNI.Clones) {
+    if (!First)
+      OS << ", ";
+    First = false;
+    OS << V;
+  }
+  First = true;
+  OS << " StackIds: ";
+  for (auto Id : SNI.StackIdIndices) {
+    if (!First)
+      OS << ", ";
+    First = false;
+    OS << Id;
+  }
+  return OS;
+}
+
 // Allocation type assigned to an allocation reached by a given context.
 // More can be added but initially this is just noncold and cold.
 // Values should be powers of two so that they can be ORed, in particular to
@@ -337,6 +358,19 @@
       : AllocType(AllocType), StackIdIndices(std::move(StackIdIndices)) {}
 };
 
+inline raw_ostream &operator<<(raw_ostream &OS, const MIBInfo &MIB) {
+  OS << "AllocType " << (unsigned)MIB.AllocType;
+  bool First = true;
+  OS << " StackIds: ";
+  for (auto Id : MIB.StackIdIndices) {
+    if (!First)
+      OS << ", ";
+    First = false;
+    OS << Id;
+  }
+  return OS;
+}
+
 /// Summary of memprof metadata on allocations.
 struct AllocInfo {
   // Used to record whole program analysis cloning decisions.
@@ -359,6 +393,22 @@
       : Versions(std::move(Versions)), MIBs(std::move(MIBs)) {}
 };
 
+inline raw_ostream &operator<<(raw_ostream &OS, const AllocInfo &AE) {
+  bool First = true;
+  OS << "Versions: ";
+  for (auto V : AE.Versions) {
+    if (!First)
+      OS << ", ";
+    First = false;
+    OS << (unsigned)V;
+  }
+  OS << " MIB:\n";
+  for (auto &M : AE.MIBs) {
+    OS << "\t\t" << M << "\n";
+  }
+  return OS;
+}
+
 /// Function and variable summary information to aid decisions and
 /// implementation of importing.
 class GlobalValueSummary {
diff --git a/llvm/unittests/IR/CMakeLists.txt b/llvm/unittests/IR/CMakeLists.txt
--- a/llvm/unittests/IR/CMakeLists.txt
+++ b/llvm/unittests/IR/CMakeLists.txt
@@ -32,6 +32,7 @@
   ManglerTest.cpp
   MetadataTest.cpp
   ModuleTest.cpp
+  ModuleSummaryIndexTest.cpp
   PassManagerTest.cpp
   PatternMatch.cpp
   ShuffleVectorInstTest.cpp
diff --git a/llvm/unittests/IR/ModuleSummaryIndexTest.cpp b/llvm/unittests/IR/ModuleSummaryIndexTest.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/unittests/IR/ModuleSummaryIndexTest.cpp
@@ -0,0 +1,57 @@
+//===- ModuleSummaryIndexTest.cpp - ModuleSummaryIndex Unit Tests-============//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/ModuleSummaryIndex.h"
+#include "llvm/AsmParser/Parser.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+static std::unique_ptr<ModuleSummaryIndex> makeLLVMIndex(const char *Summary) {
+  SMDiagnostic Err;
+  std::unique_ptr<ModuleSummaryIndex> Index =
+      parseSummaryIndexAssemblyString(Summary, Err);
+  if (!Index)
+    Err.print("ModuleSummaryIndexTest", errs());
+  return Index;
+}
+
+TEST(ModuleSummaryIndexTest, MemProfSummaryPrinting) {
+  std::unique_ptr<ModuleSummaryIndex> Index = makeLLVMIndex(R"Summary(
+^0 = module: (path: "test.o", hash: (0, 0, 0, 0, 0))
+^1 = gv: (guid: 23, summaries: (function: (module: ^0, flags: (linkage: external), insts: 2, allocs: ((versions: (none), memProf: ((type: notcold, stackIds: (1, 2, 3, 4)), (type: cold, stackIds: (1, 2, 3, 5))))))))
+^2 = gv: (guid: 25, summaries: (function: (module: ^0, flags: (linkage: external), insts: 22, calls: ((callee: ^1)), callsites: ((callee: ^1, clones: (0), stackIds: (3, 4)), (callee: ^1, clones: (0), stackIds: (3, 5))))))
+)Summary");
+
+  std::string Data;
+  raw_string_ostream OS(Data);
+
+  ASSERT_NE(Index, nullptr);
+  auto *CallsiteSummary =
+      cast<FunctionSummary>(Index->getGlobalValueSummary(/*guid=*/25));
+  for (auto &CI : CallsiteSummary->callsites())
+    OS << "\n" << CI;
+
+  auto *AllocSummary =
+      cast<FunctionSummary>(Index->getGlobalValueSummary(/*guid=*/23));
+  for (auto &AI : AllocSummary->allocs())
+    OS << "\n" << AI;
+
+  OS.flush();
+  EXPECT_EQ(Data, R"(
+Callee: 23 Clones: 0 StackIds: 2, 3
+Callee: 23 Clones: 0 StackIds: 2, 4
+Versions: 0 MIB:
+		AllocType 1 StackIds: 0, 1, 2, 3
+		AllocType 2 StackIds: 0, 1, 2, 4
+)");
+}
+} // end anonymous namespace