Index: cfe/trunk/include/clang/Driver/Options.td
===================================================================
--- cfe/trunk/include/clang/Driver/Options.td
+++ cfe/trunk/include/clang/Driver/Options.td
@@ -1822,7 +1822,6 @@
 
 def mgeneral_regs_only : Flag<["-"], "mgeneral-regs-only">, Group<m_aarch64_Features_Group>,
   HelpText<"Generate code which only uses the general purpose registers (AArch64 only)">;
-
 def mfix_cortex_a53_835769 : Flag<["-"], "mfix-cortex-a53-835769">,
   Group<m_aarch64_Features_Group>,
   HelpText<"Workaround Cortex-A53 erratum 835769 (AArch64 only)">;
@@ -1840,6 +1839,10 @@
   Group<m_Group>,
   HelpText<"Generate additional code for specified <version> of debugger ABI (AMDGPU only)">,
   MetaVarName<"<version>">;
+def mxnack : Flag<["-"], "mxnack">, Group<m_amdgpu_Features_Group>,
+  HelpText<"Enable XNACK (AMDGPU only)">;
+def mno_xnack : Flag<["-"], "mno-xnack">, Group<m_amdgpu_Features_Group>,
+  HelpText<"Disable XNACK (AMDGPU only)">;
 
 def faltivec : Flag<["-"], "faltivec">, Group<f_Group>, Flags<[DriverOption]>;
 def fno_altivec : Flag<["-"], "fno-altivec">, Group<f_Group>, Flags<[DriverOption]>;
Index: cfe/trunk/test/Driver/amdgpu-features.c
===================================================================
--- cfe/trunk/test/Driver/amdgpu-features.c
+++ cfe/trunk/test/Driver/amdgpu-features.c
@@ -5,3 +5,9 @@
 // RUN: %clang -### -target amdgcn -x cl -S -emit-llvm -mcpu=kaveri -mamdgpu-debugger-abi=1.0 %s -o - 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MAMDGPU-DEBUGGER-ABI-1-0 %s
 // CHECK-MAMDGPU-DEBUGGER-ABI-1-0: "-target-feature" "+amdgpu-debugger-insert-nops" "-target-feature" "+amdgpu-debugger-reserve-regs" "-target-feature" "+amdgpu-debugger-emit-prologue"
+
+// RUN: %clang -### -target amdgcn -mcpu=gfx700 -mxnack %s 2>&1 | FileCheck --check-prefix=XNACK %s
+// XNACK: "-target-feature" "+xnack"
+
+// RUN: %clang -### -target amdgcn -mcpu=gfx700 -mno-xnack %s 2>&1 | FileCheck --check-prefix=NO-XNACK %s
+// NO-XNACK: "-target-feature" "-xnack"