diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -1599,9 +1599,11 @@
     }
 
     assert(II && "Expected an identifier clause!");
-    StringRef Assumption = II->getName();
+    std::string Assumption = II->getName().str();
     if (ACMI.StartsWith)
-      Assumption = Assumption.substr(ACMI.Identifier.size());
+      Assumption = "ompx_" + Assumption.substr(ACMI.Identifier.size());
+    else
+      Assumption = "omp_" + Assumption;
     Assumptions.push_back(Assumption);
   }
 
diff --git a/clang/test/OpenMP/assumes_print.cpp b/clang/test/OpenMP/assumes_print.cpp
--- a/clang/test/OpenMP/assumes_print.cpp
+++ b/clang/test/OpenMP/assumes_print.cpp
@@ -37,8 +37,8 @@
 }
 #pragma omp end assumes
 
-// CHECK: void foo() __attribute__((assume("no_openmp_routines"))) __attribute__((assume("no_openmp")))
-// CHECK: void bar() __attribute__((assume("range_bar_only"))) __attribute__((assume("range_bar_only_2"))) __attribute__((assume("no_openmp_routines"))) __attribute__((assume("no_openmp")))
-// CHECK: void baz() __attribute__((assume("1234"))) __attribute__((assume("no_openmp_routines"))) __attribute__((assume("no_openmp")))
+// CHECK: void foo() __attribute__((assume("omp_no_openmp_routines"))) __attribute__((assume("omp_no_openmp")))
+// CHECK: void bar() __attribute__((assume("ompx_range_bar_only"))) __attribute__((assume("ompx_range_bar_only_2"))) __attribute__((assume("omp_no_openmp_routines"))) __attribute__((assume("omp_no_openmp")))
+// CHECK: void baz() __attribute__((assume("ompx_1234"))) __attribute__((assume("omp_no_openmp_routines"))) __attribute__((assume("omp_no_openmp")))
 
 #endif
diff --git a/clang/test/OpenMP/assumes_template_print.cpp b/clang/test/OpenMP/assumes_template_print.cpp
--- a/clang/test/OpenMP/assumes_template_print.cpp
+++ b/clang/test/OpenMP/assumes_template_print.cpp
@@ -17,7 +17,7 @@
 struct S {
   int a;
 // CHECK: template <typename T> struct S {
-// CHECK:     void foo() __attribute__((assume("global_assumption")))     {
+// CHECK:     void foo() __attribute__((assume("ompx_global_assumption")))     {
   void foo() {
     #pragma omp parallel
     {}
@@ -25,15 +25,15 @@
 };
 
 // CHECK: template<> struct S<int> {
-// CHECK:     void foo() __attribute__((assume("global_assumption")))     {
+// CHECK:     void foo() __attribute__((assume("ompx_global_assumption")))     {
 
 #pragma omp begin assumes no_openmp
-// CHECK: void S_with_assumes_no_call() __attribute__((assume("no_openmp"))) __attribute__((assume("global_assumption"))) {
+// CHECK: void S_with_assumes_no_call() __attribute__((assume("omp_no_openmp"))) __attribute__((assume("ompx_global_assumption"))) {
 void S_with_assumes_no_call() {
   S<int> s;
   s.a = 0;
 }
-// CHECK: void S_with_assumes_call() __attribute__((assume("no_openmp"))) __attribute__((assume("global_assumption"))) {
+// CHECK: void S_with_assumes_call() __attribute__((assume("omp_no_openmp"))) __attribute__((assume("ompx_global_assumption"))) {
 void S_with_assumes_call() {
   S<int> s;
   s.a = 0;
@@ -42,7 +42,7 @@
 }
 #pragma omp end assumes
 
-// CHECK: void S_without_assumes() __attribute__((assume("global_assumption"))) {
+// CHECK: void S_without_assumes() __attribute__((assume("ompx_global_assumption"))) {
 void S_without_assumes() {
   S<int> s;
   s.foo();
@@ -54,7 +54,7 @@
 template <typename T>
 struct P {
 // CHECK: template <typename T> struct P {
-// CHECK:     void foo() __attribute__((assume("global_assumption")))     {
+// CHECK:     void foo() __attribute__((assume("ompx_global_assumption")))     {
   int a;
   void foo() {
     #pragma omp parallel
@@ -65,21 +65,21 @@
 // TODO: Avoid the duplication here:
 
 // CHECK: template<> struct P<int> {
-// CHECK:     void foo() __attribute__((assume("global_assumption"))) __attribute__((assume("global_assumption")))     {
+// CHECK:     void foo() __attribute__((assume("ompx_global_assumption"))) __attribute__((assume("ompx_global_assumption")))     {
 
-// CHECK: void P_without_assumes() __attribute__((assume("global_assumption"))) {
+// CHECK: void P_without_assumes() __attribute__((assume("ompx_global_assumption"))) {
 void P_without_assumes() {
   P<int> p;
   p.foo();
 }
 
 #pragma omp begin assumes no_openmp
-// CHECK: void P_with_assumes_no_call() __attribute__((assume("no_openmp"))) __attribute__((assume("global_assumption"))) {
+// CHECK: void P_with_assumes_no_call() __attribute__((assume("omp_no_openmp"))) __attribute__((assume("ompx_global_assumption"))) {
 void P_with_assumes_no_call() {
   P<int> p;
   p.a = 0;
 }
-// CHECK: void P_with_assumes_call() __attribute__((assume("no_openmp"))) __attribute__((assume("global_assumption"))) {
+// CHECK: void P_with_assumes_call() __attribute__((assume("omp_no_openmp"))) __attribute__((assume("ompx_global_assumption"))) {
 void P_with_assumes_call() {
   P<int> p;
   p.a = 0;