diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -81,9 +81,10 @@
 
 void addCygMingDefines(const LangOptions &Opts, MacroBuilder &Builder) {
   // Mingw and cygwin define __declspec(a) to __attribute__((a)).  Clang
-  // supports __declspec natively under -fms-extensions, but we define a no-op
-  // __declspec macro anyway for pre-processor compatibility.
-  if (Opts.MicrosoftExt)
+  // supports __declspec natively under -fdeclspec (also enabled with
+  // -fms-extensions), but we define a no-op __declspec macro anyway for
+  // pre-processor compatibility.
+  if (Opts.DeclSpecKeyword)
     Builder.defineMacro("__declspec", "__declspec");
   else
     Builder.defineMacro("__declspec(a)", "__attribute__((a))");
diff --git a/clang/test/Preprocessor/init-x86.c b/clang/test/Preprocessor/init-x86.c
--- a/clang/test/Preprocessor/init-x86.c
+++ b/clang/test/Preprocessor/init-x86.c
@@ -587,11 +587,15 @@
 // I386-NETBSD:#define __i386__ 1
 // I386-NETBSD:#define i386 1
 
-// RUN: %clang_cc1 -E -dM -triple=i686-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC %s
-// RUN: %clang_cc1 -E -dM -fms-extensions -triple=i686-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC %s
-// RUN: %clang_cc1 -E -dM -triple=i686-unknown-cygwin < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC %s
-// RUN: %clang_cc1 -E -dM -fms-extensions -triple=i686-unknown-cygwin < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC %s
-// I386-DECLSPEC: #define __declspec{{.*}}
+// RUN: %clang_cc1 -E -dM -triple=i686-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-GNU %s
+// RUN: %clang_cc1 -E -dM -triple=i686-unknown-cygwin < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-GNU %s
+// I386-DECLSPEC-GNU: #define __declspec{{.*}} __attribute__{{.*}}
+
+// RUN: %clang_cc1 -E -dM -fms-extensions -triple=i686-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-MS %s
+// RUN: %clang_cc1 -E -dM -fdeclspec -triple=i686-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-MS %s
+// RUN: %clang_cc1 -E -dM -fms-extensions -triple=i686-unknown-cygwin < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-MS %s
+// RUN: %clang_cc1 -E -dM -fdeclspec -triple=i686-unknown-cygwin < /dev/null | FileCheck -match-full-lines -check-prefix I386-DECLSPEC-MS %s
+// I386-DECLSPEC-MS: #define __declspec{{.*}} __declspec{{.*}}
 
 //
 // RUN: %clang_cc1 -E -dM -ffreestanding -fgnuc-version=4.2.1 -triple=x86_64-none-none < /dev/null | FileCheck -match-full-lines -check-prefix X86_64 %s
diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1368,9 +1368,12 @@
 // RUN: %clang_cc1 -x c++ -E -dM -ffreestanding -triple=x86_64-sie-ps5 < /dev/null | FileCheck --match-full-lines --check-prefix PS4-CXX %s
 // PS4-CXX:#define __STDCPP_DEFAULT_NEW_ALIGNMENT__ 32UL
 //
-// RUN: %clang_cc1 -E -dM -triple=x86_64-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix X86-64-DECLSPEC %s
-// RUN: %clang_cc1 -E -dM -fms-extensions -triple=x86_64-unknown-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix X86-64-DECLSPEC %s
-// X86-64-DECLSPEC: #define __declspec{{.*}}
+// RUN: %clang_cc1 -E -dM -triple=x86_64-pc-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix X86-64-DECLSPEC-GNU %s
+// X86-64-DECLSPEC-GNU: #define __declspec{{.*}} __attribute__{{.*}}
+//
+// RUN: %clang_cc1 -E -dM -fms-extensions -triple=x86_64-unknown-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix X86-64-DECLSPEC-MS %s
+// RUN: %clang_cc1 -E -dM -fdeclspec -triple=x86_64-unknown-mingw32 < /dev/null | FileCheck -match-full-lines -check-prefix X86-64-DECLSPEC-MS %s
+// X86-64-DECLSPEC-MS: #define __declspec{{.*}} __declspec{{.*}}
 //
 // RUN: %clang_cc1 -E -dM -ffreestanding -triple=sparc64-none-none < /dev/null | FileCheck -match-full-lines -check-prefix SPARCV9 %s
 // SPARCV9:#define __BIGGEST_ALIGNMENT__ 16