diff --git a/unittests/ADT/APIntTest.cpp b/unittests/ADT/APIntTest.cpp
index a89a960a078..3fd4fd4c309 100644
--- a/unittests/ADT/APIntTest.cpp
+++ b/unittests/ADT/APIntTest.cpp
@@ -17,6 +17,13 @@ using namespace llvm;
 
 namespace {
 
+// Support APInt output to an std::ostream.
+inline std::ostream &operator<<(std::ostream &OS, const APInt &Value) {
+  raw_os_ostream RawOS(OS);
+  RawOS << Value;
+  return OS;
+}
+
 // Test that APInt shift left works when bitwidth > 64 and shiftamt == 0
 TEST(APIntTest, ShiftLeftByZero) {
   APInt One = APInt::getNullValue(65) + 1;
diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index f377b6f068a..56f315a09af 100644
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -16,6 +16,13 @@ using namespace llvm;
 
 namespace {
 
+// Support APInt output to an std::ostream.
+inline std::ostream &operator<<(std::ostream &OS, const APInt &Value) {
+  raw_os_ostream RawOS(OS);
+  RawOS << Value;
+  return OS;
+}
+
 class ConstantRangeTest : public ::testing::Test {
 protected:
   static ConstantRange Full;