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Fixed the handling of OR in logical expressions, and added a testcase

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This commit is contained in:
Neil Brown 2009-02-09 23:04:52 +00:00
parent 84568cfbdd
commit df34d666ba
2 changed files with 27 additions and 4 deletions
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16
checks/Check.hs
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@ -149,11 +149,19 @@ addBK mp mp2 g nid n = fmap ((,) $ followBK (map keepDefined joined')) n
where
g :: A.Expression -> And (Or BackgroundKnowledge)
g (A.Dyadic _ op lhs rhs)
-- (A or B) and (C or D) = ((A or B) and C) or ((A or B) and D)
-- = (A and C) or (B and C) or (A and D) or (B and D)
-- If one of the components of an AND is unrecognised, we still keep
-- the other part:
| op == A.And = g lhs `mappend` g rhs
-- TODO:
-- | op == A.Or = And $ map Or $ productN $ map (map deOr . deAnd) [g lhs, g rhs]
-- (A and B) or (C and D) = ((A and B) or C) and ((A and B) or D)
-- = (A or C) and (B or C) and (A or D) and (B or D)
--
-- If one component of an OR is unrecognised, we end up dropping both
-- halves because we can no longer count on that BK (given A OR B, where
-- we recognise A, since we can't tell if B is true, we actually have
-- no information about A even if the branch is taken). We do know that
-- if the branch is not taken, A cannot be true, but that's dealt with
-- because a negated OR ends up as an AND, see above.
| op == A.Or = let f = deAnd . g in And $ map (\(x,y) -> x `mappend` y) $ product2 (f lhs, f rhs)
| op == A.Eq = noAnd $ noOr $ Equal lhs rhs
| op == A.LessEq = noAnd $ noOr $ LessThanOrEqual lhs rhs
| op == A.MoreEq = noAnd $ noOr $ LessThanOrEqual rhs lhs

15
testcases/automatic/usage-check-8.occ.test
View File

@ -81,6 +81,21 @@ PROC m()
read(c[j])
TRUE
write(c[j])
%PASS Safe replicated parallel use with overlap #5
PAR
PAR i = 0 FOR 10
IF
(i = 5) OR (i >= 6)
write(c[i])
TRUE
read(c[i])
PAR j = 0 FOR 10
IF
(j >= 5) AND ((j = 5) OR (j = 6) OR (j > 6))
read(c[j])
TRUE
write(c[j])
%FAIL Unsafe replicated parallel use with overlap #3
PAR
PAR i = 0 FOR 5