Index: lib/AST/ItaniumMangle.cpp
===================================================================
--- lib/AST/ItaniumMangle.cpp
+++ lib/AST/ItaniumMangle.cpp
@@ -1459,8 +1459,6 @@
     // We do not consider restrict a distinguishing attribute for overloading
     // purposes so we must not mangle it.
     MethodQuals.removeRestrict();
-    // __unaligned is not currently mangled in any way, so remove it.
-    MethodQuals.removeUnaligned();
     mangleQualifiers(MethodQuals);
     mangleRefQualifier(Method->getRefQualifier());
   }
@@ -2208,6 +2206,9 @@
     break;
   }
 
+  if (Quals.hasUnaligned())
+      mangleVendorQualifier("__unaligned");
+
   // <CV-qualifiers> ::= [r] [V] [K]    # restrict (C99), volatile, const
   if (Quals.hasRestrict())
     Out << 'r';
@@ -4327,7 +4328,7 @@
 /// substitutions.
 static bool hasMangledSubstitutionQualifiers(QualType T) {
   Qualifiers Qs = T.getQualifiers();
-  return Qs.getCVRQualifiers() || Qs.hasAddressSpace();
+  return Qs.getCVRQualifiers() || Qs.hasAddressSpace() || Qs.hasUnaligned();
 }
 
 bool CXXNameMangler::mangleSubstitution(QualType T) {
Index: test/CodeGenCXX/pr33080.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/pr33080.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fms-extensions -emit-llvm -o- %s | FileCheck %s
+
+void fa(__unaligned struct A *) {}
+// CHECK: define void @_Z2faPU11__unaligned1A(
+
+void ga(struct A *, struct A *) {}
+// CHECK: define void @_Z2gaP1AS0_(
+
+void gb(__unaligned struct A *, struct A *) {}
+// CHECK: define void @_Z2gbPU11__unaligned1APS_(
+
+void gc(struct A *, __unaligned struct A *) {}
+// CHECK: define void @_Z2gcP1APU11__unalignedS_(
+
+void gd(__unaligned struct A *, __unaligned struct A *) {}
+// CHECK: define void @_Z2gdPU11__unaligned1AS1_(
+
+void hb(__unaligned struct A *, __unaligned const struct A *) {}
+// CHECK: define void @_Z2hbPU11__unaligned1APU11__unalignedKS_(
+
+void ja(__unaligned struct A *, __unaligned struct A *__unaligned *, __unaligned struct A *__unaligned *__unaligned *) {}
+// CHECK: define void @_Z2jaPU11__unaligned1APU11__unalignedS1_PU11__unalignedS3_(
+
+void jb(__unaligned struct A *, __unaligned struct A **, __unaligned struct A *__unaligned *__unaligned *) {}
+// CHECK: @_Z2jbPU11__unaligned1APS1_PU11__unalignedPU11__unalignedS1_(
+
+template <typename T, typename Q>
+void ta(T &, Q *) {}
+
+void ia(__unaligned struct A &a) {
+  ta(a, &a);
+}
+// CHECK: @_Z2taIU11__unaligned1AS1_EvRT_PT0_(
Index: test/CodeGenCXX/unaligned-duplicated-mangle-name.cpp
===================================================================
--- test/CodeGenCXX/unaligned-duplicated-mangle-name.cpp
+++ /dev/null
@@ -1,20 +0,0 @@
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fms-extensions -emit-llvm-only %s -verify
-
-struct A
-{
-    int x;
-    void foo() __unaligned;
-    void foo();
-};
-
-void A::foo() __unaligned
-{
-    this->x++;
-}
-
-void A::foo() // expected-error {{definition with same mangled name as another definition}}
-              // expected-note@-6 {{previous definition is here}}
-{
-    this->x++;
-}
-
Index: test/CodeGenCXX/unaligned-member-qualifier.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/unaligned-member-qualifier.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fms-extensions -emit-llvm %s -o- | FileCheck %s
+
+struct A {
+  void foo() __unaligned;
+  void foo() const __unaligned;
+  void foo() volatile __unaligned;
+  void foo() const volatile __unaligned;
+};
+
+void A::foo() __unaligned {}
+// CHECK: define void @_ZNU11__unaligned1A3fooEv(
+
+void A::foo() const __unaligned {}
+// CHECK: define void @_ZNU11__unalignedK1A3fooEv(
+
+void A::foo() volatile __unaligned {}
+// CHECK: define void @_ZNU11__unalignedV1A3fooEv(
+
+void A::foo() const volatile __unaligned {}
+// CHECK: define void @_ZNU11__unalignedVK1A3fooEv(