[X86] SimplifyDemandedBitsForTargetNode - cleanup SSE shift-by-immediate handlers. NFC.

Cleanup the SHLI/SRLI/SRAI handlers to be more consistent - prep for a future patch.

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -43375,8 +43375,9 @@ bool X86TargetLowering::SimplifyDemandedBitsForTargetNode(
  }
  case X86ISD::VSHLI: {
  SDValue Op0 = Op.getOperand(0);
+ SDValue Op1 = Op.getOperand(1);
 
- unsigned ShAmt = Op.getConstantOperandVal(1);
+ unsigned ShAmt = Op1->getAsZExtVal();
  if (ShAmt >= BitWidth)
  break;
 
@@ -43420,14 +43421,17 @@ bool X86TargetLowering::SimplifyDemandedBitsForTargetNode(
  return false;
  }
  case X86ISD::VSRLI: {
- unsigned ShAmt = Op.getConstantOperandVal(1);
+ SDValue Op0 = Op.getOperand(0);
+ SDValue Op1 = Op.getOperand(1);
+
+ unsigned ShAmt = Op1->getAsZExtVal();
  if (ShAmt >= BitWidth)
  break;
 
  APInt DemandedMask = OriginalDemandedBits << ShAmt;
 
- if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask,
- OriginalDemandedElts, Known, TLO, Depth + 1))
+ if (SimplifyDemandedBits(Op0, DemandedMask, OriginalDemandedElts, Known,
+ TLO, Depth + 1))
  return true;
 
  Known.Zero.lshrInPlace(ShAmt);
@@ -43452,8 +43456,7 @@ bool X86TargetLowering::SimplifyDemandedBitsForTargetNode(
  return TLO.CombineTo(Op, Op0);
 
  // fold (VSRAI (VSHLI X, C1), C1) --> X iff NumSignBits(X) > C1
- if (Op0.getOpcode() == X86ISD::VSHLI &&
- Op.getOperand(1) == Op0.getOperand(1)) {
+ if (Op0.getOpcode() == X86ISD::VSHLI && Op1 == Op0.getOperand(1)) {
  SDValue Op00 = Op0.getOperand(0);
  unsigned NumSignBits =
  TLO.DAG.ComputeNumSignBits(Op00, OriginalDemandedElts);