Query with a negative shift predicate yields an incorrect result

[mrigger]

Consider the following statements:

CREATE TABLE t0(c0 INT);
CREATE TABLE t1(c0 INT8, c1 DOUBLE);
INSERT INTO t1(c0) VALUES (0);
INSERT INTO t1(c1, c0) VALUES (1, 1);
INSERT INTO t0 VALUES (0);
SELECT * FROM t1 JOIN t0 ON t1.c1 WHERE NOT (t1.c0<<-1); -- expected: {1|1|0}, actual: {}

Unexpectedly, this query does not fetch a row. That the predicate should evaluate to TRUE can be seen through the following:

SELECT NOT (t1.c0<<-1) FROM t1; -- {true, true}

When removing the NOT, no row is fetched, which is expected:

SELECT * FROM t1 JOIN t0 ON t1.c1 WHERE (t1.c0<<-1); -- {}

I can reproduce this on the latest master (commit c52fc9b) and the current fix branch (commit 5c4cde5).

[Mytherin]

Fixed in 7e1234d, this had to do with the shift by a negative number triggering undefined behavior. I have modified it so a left or right shift by a negative number results in 0.