Move scalar immediate shift lowering into a dedicated func

- no functionality change



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177476 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5c2f651..71288c9 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -11491,16 +11491,13 @@
   return SDValue();
 }
 
-SDValue X86TargetLowering::LowerShift(SDValue Op, SelectionDAG &DAG) const {
-
+static SDValue LowerScalarImmediateShift(SDValue Op, SelectionDAG &DAG,
+                                         const X86Subtarget *Subtarget) {
   EVT VT = Op.getValueType();
   DebugLoc dl = Op.getDebugLoc();
   SDValue R = Op.getOperand(0);
   SDValue Amt = Op.getOperand(1);
 
-  if (!Subtarget->hasSSE2())
-    return SDValue();
-
   // Optimize shl/srl/sra with constant shift amount.
   if (isSplatVector(Amt.getNode())) {
     SDValue SclrAmt = Amt->getOperand(0);
@@ -11611,6 +11608,24 @@
     }
   }
 
+  return SDValue();
+}
+
+SDValue X86TargetLowering::LowerShift(SDValue Op, SelectionDAG &DAG) const {
+
+  EVT VT = Op.getValueType();
+  DebugLoc dl = Op.getDebugLoc();
+  SDValue R = Op.getOperand(0);
+  SDValue Amt = Op.getOperand(1);
+  SDValue V;
+
+  if (!Subtarget->hasSSE2())
+    return SDValue();
+
+  V = LowerScalarImmediateShift(Op, DAG, Subtarget);
+  if (V.getNode())
+    return V;
+
   // Lower SHL with variable shift amount.
   if (VT == MVT::v4i32 && Op->getOpcode() == ISD::SHL) {
     Op = DAG.getNode(ISD::SHL, dl, VT, Amt, DAG.getConstant(23, VT));