diff options
| author | Mark H Weaver <mhw@netris.org> | 2018-10-14 05:29:52 -0400 |
|---|---|---|
| committer | Mark H Weaver <mhw@netris.org> | 2018-10-14 05:37:18 -0400 |
| commit | 1990aa916382d0afcebd5315a6d6f555949ff654 (patch) | |
| tree | dbbf60e3713333ab39d5b795f1f0c04d05869404 /test-suite | |
| parent | 9448a078b5a35fc49a16d32c0398d5789a863f09 (diff) | |
In 'ash' and 'round-ash', handle right shift count of LONG_MIN.
Fixes <https://bugs.gnu.org/21901>.
Reported by Zefram <zefram@fysh.org>.
* libguile/numbers.c: Add another top-level 'verify' to ensure that
LONG_MIN is not a fixnum.
(scm_ash, scm_round_ash): Ensure that when the shift count is LONG_MIN,
it is not handled via the normal code path, to avoid signed overflow
when the shift count is negated.
* test-suite/tests/numbers.test: Add tests.
Diffstat (limited to 'test-suite')
| -rw-r--r-- | test-suite/tests/numbers.test | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/test-suite/tests/numbers.test b/test-suite/tests/numbers.test index 8cecb06ad..59e370ec9 100644 --- a/test-suite/tests/numbers.test +++ b/test-suite/tests/numbers.test @@ -5390,11 +5390,19 @@ (for-each (lambda (n) (for-each (lambda (count) (test n count)) `(-1000 + ,(* 2 (- fixnum-bit)) + ,(- -3 fixnum-bit) + ,(- -2 fixnum-bit) + ,(- -1 fixnum-bit) ,(- fixnum-bit) ,(- (- fixnum-bit 1)) -3 -2 -1 0 1 2 3 ,(- fixnum-bit 1) ,fixnum-bit + ,(+ fixnum-bit 1) + ,(+ fixnum-bit 2) + ,(+ fixnum-bit 3) + ,(* 2 fixnum-bit) 1000))) (list 0 1 3 23 -1 -3 -23 fixnum-max @@ -5423,6 +5431,22 @@ '(#b11001 #b11100 #b11101 #b10001 #b10100 #b10101))) (list 0 64 -64 (* 64 fixnum-max) (* 64 fixnum-min))) + ;; Right shift by LONG_MIN, typically (ash -1 63) and (ash -1 31) + ;; depending on the word size, where negating the shift count + ;; overflows. See <https://bugs.gnu.org/21901>. + (pass-if-equal "Right shift of positive integer by (ash -1 63) bits" + 0 + (ash-variant 123 (ash -1 63))) + (pass-if-equal "Right shift of negative integer by (ash -1 63) bits" + (if rounded? 0 -1) + (ash-variant -123 (ash -1 63))) + (pass-if-equal "Right shift of positive integer by (ash -1 31) bits" + 0 + (ash-variant 123 (ash -1 31))) + (pass-if-equal "Right shift of negative integer by (ash -1 31) bits" + (if rounded? 0 -1) + (ash-variant -123 (ash -1 31))) + ;; Huge shift counts (pass-if-equal "Huge left shift of 0" 0 |