public Expression visit(IntToExprCast castExpr) {
Expression ret = lookup(castExpr);
if (ret!=null) return ret;
final IntExpression intExpr = castExpr.intExpr().accept(this);
ret = (intExpr==castExpr.intExpr()) ? castExpr : intExpr.cast(castExpr.op());
return cache(castExpr, ret);
}
/**
* Calls lookup(intconst) and returns the cached value, if any.