[X86] combineExtractVectorElt - call hasOneUse() as late as possible. NFCI.

MMX conversion is very unlikely, so check the value types first, and make the more expensive hasOneUse() call as late as possible.

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index e012026..d3400ad 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -45728,24 +45728,19 @@ static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG,
   }
 
   // Detect mmx extraction of all bits as a i64. It works better as a bitcast.
-  if (InputVector.getOpcode() == ISD::BITCAST && InputVector.hasOneUse() &&
-      VT == MVT::i64 && SrcVT == MVT::v1i64 && isNullConstant(EltIdx)) {
-    SDValue MMXSrc = InputVector.getOperand(0);
-
-    // The bitcast source is a direct mmx result.
-    if (MMXSrc.getValueType() == MVT::x86mmx)
-      return DAG.getBitcast(VT, InputVector);
-  }
+  if (VT == MVT::i64 && SrcVT == MVT::v1i64 &&
+      InputVector.getOpcode() == ISD::BITCAST &&
+      InputVector.getOperand(0).getValueType() == MVT::x86mmx &&
+      isNullConstant(EltIdx) && InputVector.hasOneUse())
+    return DAG.getBitcast(VT, InputVector);
 
   // Detect mmx to i32 conversion through a v2i32 elt extract.
-  if (InputVector.getOpcode() == ISD::BITCAST && InputVector.hasOneUse() &&
-      VT == MVT::i32 && SrcVT == MVT::v2i32 && isNullConstant(EltIdx)) {
-    SDValue MMXSrc = InputVector.getOperand(0);
-
-    // The bitcast source is a direct mmx result.
-    if (MMXSrc.getValueType() == MVT::x86mmx)
-      return DAG.getNode(X86ISD::MMX_MOVD2W, dl, MVT::i32, MMXSrc);
-  }
+  if (VT == MVT::i32 && SrcVT == MVT::v2i32 &&
+      InputVector.getOpcode() == ISD::BITCAST &&
+      InputVector.getOperand(0).getValueType() == MVT::x86mmx &&
+      isNullConstant(EltIdx) && InputVector.hasOneUse())
+    return DAG.getNode(X86ISD::MMX_MOVD2W, dl, MVT::i32,
+                       InputVector.getOperand(0));
 
   // Check whether this extract is the root of a sum of absolute differences
   // pattern. This has to be done here because we really want it to happen