[RISCV] Use getBuiltinVectorTypeInfo to simplify code. NFC

Author: topperc

clang/lib/Sema/SemaChecking.cpp

@@ -5082,12 +5082,10 @@ static bool CheckInvalidVLENandLMUL(const TargetInfo &TI, CallExpr *TheCall,
   assert((EGW == 128 || EGW == 256) && "EGW can only be 128 or 256 bits");
 
   // LMUL * VLEN >= EGW
-  unsigned ElemSize = Type->isRVVType(32, false) ? 32 : 64;
-  unsigned MinElemCount = Type->isRVVType(1)   ? 1
-                          : Type->isRVVType(2) ? 2
-                          : Type->isRVVType(4) ? 4
-                          : Type->isRVVType(8) ? 8
-                                               : 16;
+  ASTContext::BuiltinVectorTypeInfo Info =
+      S.Context.getBuiltinVectorTypeInfo(Type->castAs<BuiltinType>());
+  unsigned ElemSize = S.Context.getTypeSize(Info.ElementType);
+  unsigned MinElemCount = Info.EC.getKnownMinValue();
 
   unsigned EGS = EGW / ElemSize;
   // If EGS is less than or equal to the minimum number of elements, then the