diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3493,7 +3493,7 @@
 def CFGuard : InheritableAttr {
   // Currently only the __declspec(guard(nocf)) modifier is supported. In future
   // we might also want to support __declspec(guard(suppress)).
-  let Spellings = [Declspec<"guard">];
+  let Spellings = [Declspec<"guard">, GCC<"guard">];
   let Subjects = SubjectList<[Function]>;
   let Args = [EnumArgument<"Guard", "GuardArg", ["nocf"], ["nocf"]>];
   let Documentation = [CFGuardDocs];
diff --git a/clang/test/CodeGen/guard_nocf_mingw.c b/clang/test/CodeGen/guard_nocf_mingw.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/guard_nocf_mingw.c
@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm -O2 -o - %s | FileCheck %s
+
+void target_func(void);
+void (*func_ptr)(void) = &target_func;
+
+// The "guard_nocf" attribute must be added.
+__attribute((guard(nocf))) void nocf0(void) {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf0
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// The "guard_nocf" attribute must *not* be added.
+void cf0(void) {
+  (*func_ptr)();
+}
+// CHECK-LABEL: cf0
+// CHECK: call{{.*}}[[CF:#[0-9]+]]
+
+// If the modifier is present on either the function declaration or definition,
+// the "guard_nocf" attribute must be added.
+__attribute__((guard(nocf))) void nocf1(void);
+void nocf1(void) {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf1
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+void nocf2(void);
+__attribute__((guard(nocf))) void nocf2(void) {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf2
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// When inlining a function, the "guard_nocf" attribute on indirect calls must
+// be preserved.
+void nocf3(void) {
+  nocf0();
+}
+// CHECK-LABEL: nocf3
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// When inlining into a function marked as __attribute__((guard(nocf))), the
+// "guard_nocf" attribute must *not* be added to the inlined calls.
+__attribute__((guard(nocf))) void cf1(void) {
+  cf0();
+}
+// CHECK-LABEL: cf1
+// CHECK: call{{.*}}[[CF:#[0-9]+]]
+
+// CHECK: attributes [[NOCF]] = { {{.*}}"guard_nocf"{{.*}} }
+// CHECK-NOT: attributes [[CF]] = { {{.*}}"guard_nocf"{{.*}} }
diff --git a/clang/test/CodeGenCXX/guard_nocf_mingw.cpp b/clang/test/CodeGenCXX/guard_nocf_mingw.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenCXX/guard_nocf_mingw.cpp
@@ -0,0 +1,84 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++11 -emit-llvm -O2 -o - %s | FileCheck %s
+
+void target_func();
+void (*func_ptr)() = &target_func;
+
+// The "guard_nocf" attribute must be added.
+__attribute__((guard(nocf))) void nocf0() {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf0
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// The "guard_nocf" attribute must *not* be added.
+void cf0() {
+  (*func_ptr)();
+}
+// CHECK-LABEL: cf0
+// CHECK: call{{.*}}[[CF:#[0-9]+]]
+
+// If the modifier is present on either the function declaration or definition,
+// the "guard_nocf" attribute must be added.
+__attribute__((guard(nocf))) void nocf1();
+void nocf1() {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf1
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+void nocf2();
+__attribute__((guard(nocf))) void nocf2() {
+  (*func_ptr)();
+}
+// CHECK-LABEL: nocf2
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// When inlining a function, the "guard_nocf" attribute on indirect calls must
+// be preserved.
+void nocf3() {
+  nocf0();
+}
+// CHECK-LABEL: nocf3
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// When inlining into a function marked as __attribute__((guard(nocf))), the
+// "guard_nocf" attribute must *not* be added to the inlined calls.
+__attribute__((guard(nocf))) void cf1() {
+  cf0();
+}
+// CHECK-LABEL: cf1
+// CHECK: call{{.*}}[[CF:#[0-9]+]]
+
+// When the __attribute__((guard(nocf))) modifier is present on an override
+// function, the "guard_nocf" attribute must be added.
+struct Base {
+  virtual void nocf4();
+};
+
+struct Derived : Base {
+  __attribute__((guard(nocf))) void nocf4() override {
+    (*func_ptr)();
+  }
+};
+Derived d;
+// CHECK-LABEL: nocf4
+// CHECK: call{{.*}}[[NOCF:#[0-9]+]]
+
+// When the modifier is not present on an override function, the "guard_nocf"
+// attribute must *not* be added, even if the modifier is present on the virtual
+// function.
+struct Base1 {
+  __attribute__((guard(nocf))) virtual void cf2();
+};
+
+struct Derived1 : Base1 {
+  void cf2() override {
+    (*func_ptr)();
+  }
+};
+Derived1 d1;
+// CHECK-LABEL: cf2
+// CHECK: call{{.*}}[[CF:#[0-9]+]]
+
+// CHECK: attributes [[NOCF]] = { {{.*}}"guard_nocf"{{.*}} }
+// CHECK-NOT: attributes [[CF]] = { {{.*}}"guard_nocf"{{.*}} }
diff --git a/clang/test/Sema/attr-guard_nocf_mingw.c b/clang/test/Sema/attr-guard_nocf_mingw.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Sema/attr-guard_nocf_mingw.c
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -verify -fsyntax-only %s
+// RUN: %clang_cc1 -triple %itanium_abi_triple -verify -std=c++11 -fsyntax-only -x c++ %s
+
+// Function definition.
+__attribute__((guard(nocf))) void testGuardNoCF(void) { // no warning
+}
+
+// Can not be used on variable, parameter, or function pointer declarations.
+int __attribute__((guard(nocf))) i;                                      // expected-warning {{'guard' attribute only applies to functions}}
+void testGuardNoCFFuncParam(double __attribute__((guard(nocf))) i) {}    // expected-warning {{'guard' attribute only applies to functions}}
+__attribute__((guard(nocf))) typedef void (*FuncPtrWithGuardNoCF)(void); // expected-warning {{'guard' attribute only applies to functions}}
+
+// 'guard' Attribute requries an argument.
+__attribute__((guard)) void testGuardNoCFParams(void) { // expected-error {{'guard' attribute takes one argument}}
+}
+
+// 'guard' Attribute requries an identifier as argument.
+__attribute__((guard(1))) void testGuardNoCFParamType(void) { // expected-error {{'guard' attribute requires an identifier}}
+}
+
+// 'guard' Attribute only takes a single argument.
+__attribute__((guard(nocf, nocf))) void testGuardNoCFTooManyParams(void) { // expected-error {{use of undeclared identifier 'nocf'}}
+}
+
+// 'guard' Attribute argument must be a supported identifier.
+__attribute__((guard(cf))) void testGuardNoCFInvalidParam(void) { // expected-warning {{'guard' attribute argument not supported: 'cf'}}
+}
diff --git a/llvm/test/CodeGen/AArch64/cfguard-checks.ll b/llvm/test/CodeGen/AArch64/cfguard-checks.ll
--- a/llvm/test/CodeGen/AArch64/cfguard-checks.ll
+++ b/llvm/test/CodeGen/AArch64/cfguard-checks.ll
@@ -1,4 +1,5 @@
 ; RUN: llc < %s -mtriple=aarch64-pc-windows-msvc | FileCheck %s
+; RUN: llc < %s -mtriple=aarch64-pc-windows-gnu | FileCheck %s
 ; Control Flow Guard is currently only available on Windows
 
 ; Test that Control Flow Guard checks are correctly added when required.
diff --git a/llvm/test/CodeGen/ARM/cfguard-checks.ll b/llvm/test/CodeGen/ARM/cfguard-checks.ll
--- a/llvm/test/CodeGen/ARM/cfguard-checks.ll
+++ b/llvm/test/CodeGen/ARM/cfguard-checks.ll
@@ -1,4 +1,5 @@
 ; RUN: llc < %s -mtriple=arm-pc-windows-msvc | FileCheck %s
+; RUN: llc < %s -mtriple=arm-pc-windows-gnu | FileCheck %s
 ; Control Flow Guard is currently only available on Windows
 
 ; Test that Control Flow Guard checks are correctly added when required.
diff --git a/llvm/test/CodeGen/X86/cfguard-checks.ll b/llvm/test/CodeGen/X86/cfguard-checks.ll
--- a/llvm/test/CodeGen/X86/cfguard-checks.ll
+++ b/llvm/test/CodeGen/X86/cfguard-checks.ll
@@ -1,5 +1,7 @@
 ; RUN: llc < %s -mtriple=i686-pc-windows-msvc | FileCheck %s -check-prefix=X32
 ; RUN: llc < %s -mtriple=x86_64-pc-windows-msvc | FileCheck %s -check-prefix=X64
+; RUN: llc < %s -mtriple=i686-pc-windows-gnu | FileCheck %s -check-prefix=X32
+; RUN: llc < %s -mtriple=x86_64-pc-windows-gnu | FileCheck %s -check-prefix=X64
 ; Control Flow Guard is currently only available on Windows
 
 ; Test that Control Flow Guard checks are correctly added when required.