presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/CanonicalizeExpressionRewriter.java/CanonicalizeExpressionRewriter/rewriteArithmeticBinary
class CanonicalizeExpressionRewriter:        @Override
        public Expression rewriteArithmeticBinary(ArithmeticBinaryExpression node, Void context, ExpressionTreeRewriter<Void> treeRewriter)
        {
            if (node.getOperator() == MULTIPLY || node.getOperator() == ADD) {
                // if we have a operation of the form <constant> [+|*] <expr>, normalize it to
                // <expr> [+|*] <constant>
                if (isConstant(node.getLeft()) && !isConstant(node.getRight())) {
                    node = new ArithmeticBinaryExpression(node.getOperator(), node.getRight(), node.getLeft());
                }
            }

            return treeRewriter.defaultRewrite(node, context);
        }