diff --git a/lib/AST/ItaniumCXXABI.cpp b/lib/AST/ItaniumCXXABI.cpp
index 5784660..8928e66 100644
--- a/lib/AST/ItaniumCXXABI.cpp
+++ b/lib/AST/ItaniumCXXABI.cpp
@@ -59,6 +59,10 @@ public:
   }
 
   CallingConv getDefaultMethodCallConv(bool isVariadic) const {
+    const llvm::Triple &T = Context.getTargetInfo().getTriple();
+    if (!isVariadic && T.getOS() == llvm::Triple::MinGW32 &&
+        T.getArch() == llvm::Triple::x86)
+      return CC_X86ThisCall;
     return CC_C;
   }
 
diff --git a/test/CodeGenCXX/mingw-new-abi.cpp b/test/CodeGenCXX/mingw-new-abi.cpp
new file mode 100644
index 0000000..2b05253
--- /dev/null
+++ b/test/CodeGenCXX/mingw-new-abi.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -emit-llvm -triple i386-pc-mingw32 %s -o - | FileCheck --check-prefix=MINGW %s
+// RUN: %clang_cc1 -emit-llvm -triple i386-pc-cygwin %s -o - | FileCheck --check-prefix=CYGWIN %s
+
+namespace test1 {
+  struct foo {
+    //  MINGW: declare x86_thiscallcc void @_ZN5test13foo1fEv
+    //  CYGWIN: declare void @_ZN5test13foo1fEv
+    void f();
+  };
+  void g(foo *x) {
+    x->f();
+  }
+}