diff --git a/lib/AST/MicrosoftMangle.cpp b/lib/AST/MicrosoftMangle.cpp
index 918e5d4..40f8730 100644
--- a/lib/AST/MicrosoftMangle.cpp
+++ b/lib/AST/MicrosoftMangle.cpp
@@ -1519,12 +1519,38 @@
 
 void MicrosoftCXXNameMangler::mangleType(const VectorType *T,
                                          SourceRange Range) {
-  DiagnosticsEngine &Diags = Context.getDiags();
-  unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
-    "cannot mangle this vector type yet");
-  Diags.Report(Range.getBegin(), DiagID)
-    << Range;
+  const BuiltinType *ET = T->getElementType()->getAs<BuiltinType>();
+  assert(ET && "vectors with non-builtin elements are unsupported");
+  uint64_t Width = getASTContext().getTypeSize(T);
+  // Pattern match exactly the typedefs in our intrinsic headers.  Anything that
+  // doesn't match the Intel types uses a custom mangling below.
+  bool IntelVector = true;
+  if (Width == 64 && ET->getKind() == BuiltinType::LongLong) {
+    Out << "T__m64";
+  } else if (Width == 128 || Width == 256) {
+    if (ET->getKind() == BuiltinType::Float)
+      Out << "T__m" << Width;
+    else if (ET->getKind() == BuiltinType::LongLong)
+      Out << "T__m" << Width << 'i';
+    else if (ET->getKind() == BuiltinType::Double)
+      Out << "U__m" << Width << 'd';
+    else
+      IntelVector = false;
+  } else {
+    IntelVector = false;
+  }
+
+  if (!IntelVector) {
+    // The MS ABI doesn't have a special mangling for vector types, so we define
+    // our own mangling to handle uses of __vector_size__ on user-specified
+    // types, and for extensions like __v4sf.
+    Out << "T__clang_vec" << T->getNumElements() << '_';
+    mangleType(ET, Range);
+  }
+
+  Out << "@@";
 }
+
 void MicrosoftCXXNameMangler::mangleType(const ExtVectorType *T,
                                          SourceRange Range) {
   DiagnosticsEngine &Diags = Context.getDiags();
diff --git a/test/CodeGenCXX/mangle-ms-vector-types.cpp b/test/CodeGenCXX/mangle-ms-vector-types.cpp
new file mode 100644
index 0000000..64cb725
--- /dev/null
+++ b/test/CodeGenCXX/mangle-ms-vector-types.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -fms-extensions -ffreestanding -target-feature +avx -emit-llvm %s -o - -cxx-abi microsoft -triple=i686-pc-win32 | FileCheck %s
+
+#include <xmmintrin.h>
+#include <emmintrin.h>
+#include <immintrin.h>
+
+void foo64(__m64) {}
+// CHECK: define void @"\01?foo64@@YAXT__m64@@@Z"
+
+void foo128(__m128) {}
+// CHECK: define void @"\01?foo128@@YAXT__m128@@@Z"
+
+void foo128d(__m128d) {}
+// CHECK: define void @"\01?foo128d@@YAXU__m128d@@@Z"
+
+void foo128i(__m128i) {}
+// CHECK: define void @"\01?foo128i@@YAXT__m128i@@@Z"
+
+void foo256(__m256) {}
+// CHECK: define void @"\01?foo256@@YAXT__m256@@@Z"
+
+void foo256d(__m256d) {}
+// CHECK: define void @"\01?foo256d@@YAXU__m256d@@@Z"
+
+void foo256i(__m256i) {}
+// CHECK: define void @"\01?foo256i@@YAXT__m256i@@@Z"
+
+// We have a custom mangling for vector types not standardized by Intel.
+void foov8hi(__v8hi) {}
+// CHECK: define void @"\01?foov8hi@@YAXT__clang_vec8_F@@@Z"
+
+// Clang does not support vectors of complex types, so we can't test the
+// mangling of them.