Index: lib/CodeGen/CGVTables.cpp
===================================================================
--- lib/CodeGen/CGVTables.cpp
+++ lib/CodeGen/CGVTables.cpp
@@ -322,8 +322,6 @@
   // Consider return adjustment if we have ThunkInfo.
   if (Thunk && !Thunk->Return.isEmpty())
     RV = PerformReturnAdjustment(*this, ResultType, RV, *Thunk);
-  else if (llvm::CallInst* Call = dyn_cast<llvm::CallInst>(CallOrInvoke))
-    Call->setTailCallKind(llvm::CallInst::TCK_Tail);
 
   // Emit return.
   if (!ResultType->isVoidType() && Slot.isNull())
Index: test/CodeGenCXX/microsoft-abi-structors.cpp
===================================================================
--- test/CodeGenCXX/microsoft-abi-structors.cpp
+++ test/CodeGenCXX/microsoft-abi-structors.cpp
@@ -177,7 +177,7 @@
 //      Do an adjustment from B* to C*.
 // DTORS2:   getelementptr i8, i8* %{{.*}}, i32 -4
 // DTORS2:   bitcast i8* %{{.*}} to %"struct.dtor_in_second_nvbase::C"*
-// DTORS2:   %[[CALL:.*]] = tail call x86_thiscallcc i8* @"\01??_GC@dtor_in_second_nvbase@@UAEPAXI@Z"
+// DTORS2:   %[[CALL:.*]] = call x86_thiscallcc i8* @"\01??_GC@dtor_in_second_nvbase@@UAEPAXI@Z"
 // DTORS2:   ret i8* %[[CALL]]
 
 }
Index: test/CodeGenCXX/tail-byval.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/tail-byval.cpp
@@ -0,0 +1,112 @@
+// RUN: %clang_cc1 %s -I%S -isystem %S/Inputs -emit-llvm -triple i386-apple-darwin9 -Wno-incompatible-ms-struct -o - -Os | opt - -dse -S -o - | FileCheck %s
+#pragma ms_struct on
+
+#include <stddef.h>
+#include <stdint.h>
+
+extern "C" int rand();
+
+struct
+IByteStream
+{
+public:
+};
+
+
+class IEmpty {};
+
+class CRepro
+{
+protected:
+	CRepro( IEmpty* p) : mp(p) {};
+	virtual ~CRepro()  {}
+	
+	IEmpty* mp;
+};
+
+class BStream : public CRepro, public IByteStream
+{
+protected:
+	BStream( IEmpty *p);
+	virtual ~BStream(){} ;
+	
+protected:
+	int32_t Ref;
+};
+
+class CStream : public BStream
+{
+public:
+        static uint32_t Create(uint32_t m, IByteStream **ppS, IEmpty *p);
+private:
+	CStream(bool fD, bool fZero,  IEmpty *p) ;
+};
+
+typedef union _LARGE {
+	struct {
+		uint32_t Low;
+		int32_t High;
+	} DUMMYSTRUCTNAME;
+	struct {
+		uint32_t Low;
+		int32_t High;
+	} u;
+	int64_t Quad;
+} LARGE;
+
+class I
+{
+public:
+	virtual uint32_t Seek(LARGE dlibMove, uint32_t Origin, LARGE *plibNP) = 0;
+	
+};
+
+class CBase : public CRepro
+{
+protected:
+	CBase(IByteStream *ps,  IEmpty *p);
+	virtual ~CBase() {};
+	
+protected:
+	uint64_t Offset;
+	uint32_t ThreadId;
+};
+
+class C : public CBase, public I
+{
+public:
+        static uint32_t Create(IByteStream *ps,  wchar_t *w,  I **ppi,  IEmpty *p);
+	uint32_t Seek(LARGE dlibMove, uint32_t Origin, LARGE *plibNP);
+	
+private:
+	C(IByteStream *ps,  IEmpty *p) ;
+	~C() {};
+	
+};
+
+uint32_t C::Seek(LARGE dlibMove, uint32_t Origin, LARGE *plibNP)
+{
+	uint32_t hr = 1;
+	
+	if (Origin != 1 || dlibMove.Quad != 0)
+	{
+		if (ThreadId != 0 && ThreadId != (uint32_t)rand())
+		{
+			hr = 3;
+			goto LError;
+		}
+		
+		if (Origin == 0)
+		{
+			Offset = (uint64_t) dlibMove.Quad;
+		}
+	}
+	
+LError:
+	if (plibNP != NULL)
+		(*plibNP).Quad = Offset;
+	return hr;
+}
+// CHECK: define i32 @_ZThn20_N1C4SeekE6_LARGEjPS0_
+// CHECK: store i64
+// CHECK: ret