Congruences: Make % sound by restricting cases where we return a constant
#1161
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Maybe we should contribute these to sv-comp: That we did not spot these issues so far is indicative of the tests there maybe lacking some non-const cases that are not super involved. |
michael-schwarz
changed the title
% sound by restricting cases where we return a constant
sim642
approved these changes
Sep 13, 2023
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For
(c1, m1) % kwithkconstant only return a constant whenkdividesm1(already here before), i.e. result will be+/- c1%kand one of the following hold:
c1%kis0(sign does not matter)(c1, m1)is a constant (sign will be correct)This addresses the soundness part of #1156, leaving it open how to become more precise again (by making use of the sign of the left argument where it is known).