diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index e1a809608a5..8b607b443ee 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3438,9 +3438,9 @@ SDValue SelectionDAGLegalize::LegalizeOp(SDValue Op) {
       const Value *V = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
       SDValue VAList = DAG.getLoad(TLI.getPointerTy(), Tmp1, Tmp2, V, 0);
       // Increment the pointer, VAList, to the next vaarg
-      Tmp3 = DAG.getNode(ISD::ADD, TLI.getPointerTy(), VAList, 
-                         DAG.getConstant(VT.getSizeInBits()/8,
-                                         TLI.getPointerTy()));
+      Tmp3 = DAG.getNode(ISD::ADD, TLI.getPointerTy(), VAList,
+        DAG.getConstant(TLI.getTargetData()->getABITypeSize(VT.getTypeForMVT()),
+                        TLI.getPointerTy()));
       // Store the incremented VAList to the legalized pointer
       Tmp3 = DAG.getStore(VAList.getValue(1), Tmp3, Tmp2, V, 0);
       // Load the actual argument out of the pointer VAList
diff --git a/test/CodeGen/X86/2008-11-03-F80VAARG.ll b/test/CodeGen/X86/2008-11-03-F80VAARG.ll
new file mode 100644
index 00000000000..bb9fbdba4ae
--- /dev/null
+++ b/test/CodeGen/X86/2008-11-03-F80VAARG.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | llc -march=x86 -o - | not grep 10
+
+declare void @llvm.va_start(i8*) nounwind
+
+declare void @llvm.va_copy(i8*, i8*) nounwind
+
+declare void @llvm.va_end(i8*) nounwind
+
+define x86_fp80 @test(...) nounwind {
+	%ap = alloca i8*		; <i8**> [#uses=3]
+	%v1 = bitcast i8** %ap to i8*		; <i8*> [#uses=1]
+	call void @llvm.va_start(i8* %v1)
+	%t1 = va_arg i8** %ap, x86_fp80		; <x86_fp80> [#uses=1]
+	%t2 = va_arg i8** %ap, x86_fp80		; <x86_fp80> [#uses=1]
+	%t = add x86_fp80 %t1, %t2		; <x86_fp80> [#uses=1]
+	ret x86_fp80 %t
+}