diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index d1f901e5da14..e43fd508de30 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2728,7 +2728,7 @@ void X86DAGToDAGISel::Select(SDNode *Node) {
       // Get the low part if needed. Don't use getCopyFromReg for aliasing
       // registers.
       if (!SDValue(Node, 0).use_empty())
-        ReplaceUses(SDValue(Node, 1),
+        ReplaceUses(SDValue(Node, 0),
           CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
 
       // Shift AX down 8 bits.