[X86] foldVectorXorShiftIntoCmp - use isConstOrConstSplat. NFCI.

Use the isConstOrConstSplat helper instead of inspecting the build vector manually.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364024 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 4e93ca60be414a36ef08122135fa808a39fcef7b..e15acc7d99317e27a54d9eab965e49a7e81d47a4 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -38842,13 +38842,10 @@ static SDValue foldVectorXorShiftIntoCmp(SDNode *N, SelectionDAG &DAG,
     return SDValue();
 
   // The shift should be smearing the sign bit across each vector element.
-  auto *ShiftBV = dyn_cast<BuildVectorSDNode>(Shift.getOperand(1));
-  if (!ShiftBV)
-    return SDValue();
-
-  EVT ShiftEltTy = Shift.getValueType().getVectorElementType();
-  auto *ShiftAmt = ShiftBV->getConstantSplatNode();
-  if (!ShiftAmt || ShiftAmt->getZExtValue() != ShiftEltTy.getSizeInBits() - 1)
+  auto *ShiftAmt =
+      isConstOrConstSplat(Shift.getOperand(1), /*AllowUndefs*/ true);
+  if (!ShiftAmt ||
+      ShiftAmt->getAPIntValue() != (Shift.getScalarValueSizeInBits() - 1))
     return SDValue();
 
   // Create a greater-than comparison against -1. We don't use the more obvious