diff --git a/llvm/unittests/Support/TargetParserTest.cpp b/llvm/unittests/Support/TargetParserTest.cpp
--- a/llvm/unittests/Support/TargetParserTest.cpp
+++ b/llvm/unittests/Support/TargetParserTest.cpp
@@ -9,6 +9,7 @@
 #include "llvm/Support/TargetParser.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/ARMBuildAttributes.h"
+#include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 #include <string>
 
@@ -31,6 +32,18 @@
     "iwmmxt2",      "xscale",      "armv8.1-m.main",
 };
 
+void printDifferingBits(uint64_t a, uint64_t b)
+{
+  llvm::errs() << "Differing bits are:";
+  uint64_t bit = 1;
+  for (int i = 0; i < 64; i++) {
+    if ((a & bit) != (b & bit))
+      llvm::errs() << " " << i;
+    bit <<= 1;
+  }
+  llvm::errs() << "\n";
+}
+
 bool testARMCPU(StringRef CPUName, StringRef ExpectedArch,
                 StringRef ExpectedFPU, uint64_t ExpectedFlags,
                 StringRef CPUAttr) {
@@ -40,10 +53,22 @@
   pass &= ARM::getFPUName(FPUKind).equals(ExpectedFPU);
 
   uint64_t ExtKind = ARM::getDefaultExtensions(CPUName, AK);
-  if (ExtKind > 1 && (ExtKind & ARM::AEK_NONE))
+  if (ExtKind > 1 && (ExtKind & ARM::AEK_NONE)) {
     pass &= ((ExtKind ^ ARM::AEK_NONE) == ExpectedFlags);
-  else
+    if (!pass) {
+      llvm::errs() << "ExpectedFlags = " << ExpectedFlags
+        << " do not equal ExtKind = " << ExtKind
+        << "in the ARM::AEK_NONE case. " << "\n";
+      printDifferingBits(ExtKind, ExpectedFlags);
+    }
+  } else {
     pass &= (ExtKind == ExpectedFlags);
+    if (!pass) {
+      llvm::errs() << "ExpectedFlags = " << ExpectedFlags
+        << " do not equal ExtKind = " << ExtKind << "\n";
+      printDifferingBits(ExtKind, ExpectedFlags);
+    }
+  }
   pass &= ARM::getCPUAttr(AK).equals(CPUAttr);
 
   return pass;
@@ -807,11 +832,22 @@
   bool pass = AArch64::getArchName(AK).equals(ExpectedArch);
 
   uint64_t ExtKind = AArch64::getDefaultExtensions(CPUName, AK);
-  if (ExtKind > 1 && (ExtKind & AArch64::AEK_NONE))
+  if (ExtKind > 1 && (ExtKind & AArch64::AEK_NONE)) {
     pass &= ((ExtKind ^ AArch64::AEK_NONE) == ExpectedFlags);
-  else
+    if (!pass) {
+      llvm::errs() << "ExpectedFlags = 0x" << ExpectedFlags
+        << " do not equal ExtKind = 0x" << ExtKind
+        << "in the ARM::AEK_NONE case. " << "\n";
+      printDifferingBits(ExtKind, ExpectedFlags);
+    }
+  } else {
     pass &= (ExtKind == ExpectedFlags);
-
+    if (!pass) {
+      llvm::errs() << "ExpectedFlags = 0x" << ExpectedFlags
+        << " do not equal ExtKind = 0x" << ExtKind << "\n";
+      printDifferingBits(ExtKind, ExpectedFlags);
+    }
+  }
   pass &= AArch64::getCPUAttr(AK).equals(CPUAttr);
 
   return pass;