Index: lib/CodeGen/CodeGenTBAA.cpp
===================================================================
--- lib/CodeGen/CodeGenTBAA.cpp
+++ lib/CodeGen/CodeGenTBAA.cpp
@@ -101,6 +101,10 @@
   if (TypeHasMayAlias(QTy))
     return getChar();
 
+  // Vector types should alias with their element types.
+  if (auto *VT = QTy->getAs<VectorType>())
+    QTy = VT->getElementType();
+
   const Type *Ty = Context.getCanonicalType(QTy).getTypePtr();
 
   if (llvm::MDNode *N = MetadataCache[Ty])
Index: test/CodeGen/tbaa-vector.cpp
===================================================================
--- /dev/null
+++ test/CodeGen/tbaa-vector.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -O1 -no-struct-path-tbaa -disable-llvm-passes %s -emit-llvm -o - | FileCheck %s
+
+typedef double __m256d __attribute__((__vector_size__(32)));
+__m256d foo(double *x, __m256d *y) {
+  *x = 0.0;
+  return *y;
+
+// CHECK-LABEL: define <4 x double> @_Z3fooPdPDv4_d
+// CHECK: store double 0.000000e+00, double* %{{.*}}, align 8, !tbaa [[TAG_double:!.*]]
+// CHECK: load <4 x double>, <4 x double>* %{{.*}}, align {{.*}}, !tbaa [[TAG_double]]
+}
+
+// CHECK: [[TYPE_char:!.*]] = !{!"omnipotent char", [[TAG_cxx_tbaa:!.*]],
+// CHECK: [[TAG_cxx_tbaa]] = !{!"Simple C++ TBAA"}
+// CHECK: [[TAG_double]] = !{[[TYPE_double:!.*]], [[TYPE_double]], i64 0}
+// CHECK: [[TYPE_double]] = !{!"double", [[TYPE_char]],
+