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Avoid ash with arguments that might overflow in (language cps types)

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Fixes https://debbugs.gnu.org/50609

* module/languages/cps/types.scm (ulsh): As stated.
This commit is contained in:
Daniel Llorens 2021-11-04 16:02:42 +01:00
parent bf9d30f3c3
commit c6b1171c6b
1 changed files with 3 additions and 1 deletions
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4
module/language/cps/types.scm
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@ -1444,7 +1444,9 @@ minimum, and maximum."
(define! result &s64 &s64-min &s64-max))))
(define-type-inferrer (ulsh a b result)
(if (<= (ash (&max/u64 a) (&max/u64 b)) &u64-max)
(if (and
(or (zero? (&max/u64 a)) (< (&max/u64 b) 64)) ; don't even try
(<= (ash (&max/u64 a) (&max/u64 b)) &u64-max))
;; No overflow; we can be precise.
(define! result &u64
(ash (&min/0 a) (&min/0 b))