[X86] detectZextAbsDiff - use m_SpecificVectorElementVT matcher. NFC. (#146498)

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -45998,12 +45998,11 @@ static bool detectZextAbsDiff(SDValue Abs, SDValue &Op0, SDValue &Op1) {
   using namespace SDPatternMatch;
 
   // Check if the operands of the sub are zero-extended from vectors of i8.
-  EVT SrcVT0, SrcVT1;
-  return sd_match(Abs,
-                  m_Abs(m_Sub(m_AllOf(m_Value(Op0), m_ZExt(m_VT(SrcVT0))),
-                              m_AllOf(m_Value(Op1), m_ZExt(m_VT(SrcVT1)))))) &&
-         SrcVT0.getVectorElementType() == MVT::i8 &&
-         SrcVT1.getVectorElementType() == MVT::i8;
+  return sd_match(
+      Abs,
+      m_Abs(m_Sub(
+          m_AllOf(m_Value(Op0), m_ZExt(m_SpecificVectorElementVT(MVT::i8))),
+          m_AllOf(m_Value(Op1), m_ZExt(m_SpecificVectorElementVT(MVT::i8))))));
 }
 
 static SDValue createVPDPBUSD(SelectionDAG &DAG, SDValue LHS, SDValue RHS,