diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index 52fe20c..dfb3f33 100644
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -2140,7 +2140,7 @@
         CmdArgs.push_back("-msave-temp-labels");
       } else if (Value == "--fatal-warnings") {
         CmdArgs.push_back("-massembler-fatal-warnings");
-      } else if (Value == "--no-warn") {
+      } else if (Value == "--no-warn" || Value == "-W") {
         CmdArgs.push_back("-massembler-no-warn");
       } else if (Value == "--noexecstack") {
         UseNoExecStack = true;
diff --git a/test/Driver/as-w-option.c b/test/Driver/as-w-option.c
new file mode 100644
index 0000000..afaf1cf
--- /dev/null
+++ b/test/Driver/as-w-option.c
@@ -0,0 +1,14 @@
+// RUN: %clang -### %s -c -o tmp.o -fno-integrated-as -Wa,-W 2>&1 | FileCheck -check-prefix=CHECK-NOIAS %s
+// RUN: %clang -### %s -c -o tmp.o -integrated-as -Wa,-W 2>&1 | FileCheck -check-prefix=CHECK-IAS %s
+// RUN: %clang %s -c -o %t.o -integrated-as -Wa,-W 2>&1 | FileCheck -allow-empty --check-prefix=CHECK-AS-NOWARN %s
+// RUN: %clang %s -c -o %t.o -fno-integrated-as -Wa,-W 2>&1 | FileCheck -allow-empty --check-prefix=CHECK-AS-NOWARN %s
+// RUN: not %clang %s -c -o %t.o -integrated-as -Wa,--fatal-warnings 2>&1 | FileCheck --check-prefix=CHECK-AS-FATAL %s
+// RUN: not %clang %s -c -o %t.o -fno-integrated-as -Wa,--fatal-warnings 2>&1 | FileCheck --check-prefix=CHECK-AS-FATAL %s
+
+// CHECK-IAS: "-cc1" {{.*}} "-massembler-no-warn"
+// CHECK-NOIAS: "-W"
+// CHECK-AS-NOWARN-NOT: warning:
+// CHECK-AS-FATAL-NOT: warning:
+// CHECK-AS-FATAL: error
+
+__asm(".warning");