Fix precondition of conditionalNegate()
#6
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`conditionalNegate()` was asserting that if we negate the input, then the input cannot correspond to `100...0`. However, this is problematic when the operation is used conditionally. This is for example necessary in `convertFloatToSBV()`, where we want to apply the negation if the result is not the safe overflow value. This commit removes the assertion and adds a comment to `conditionalNegate()` that documents why we cannot have an assertion there. Additionally, the commit makes `convertFloatToSBV()` safer by explicitly handling the safe overflow case. Previously, we negated such a value, even though it cannot be negated. This worked out in the cvc5 case (because it blindly computes `~x + 1` without asserting anything), but could be dangerous.
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conditionalNegate()was asserting that if we negate the input, thenthe input cannot correspond to
100...0. However, this is problematicwhen the operation is used conditionally. This is for example necessary
in
convertFloatToSBV(), where we want to apply the negation if theresult is not the safe overflow value. This commit removes the assertion
and adds a comment to
conditionalNegate()that documents why we cannothave an assertion there.
Additionally, the commit makes
convertFloatToSBV()safer by explicitlyhandling the safe overflow case. Previously, we negated such a value,
even though it cannot be negated. This worked out in the cvc5 case
(because it blindly computes
~x + 1without asserting anything), butcould be dangerous.