destructive equality resolution uses an occurs check function that is only safe for quantifier-free formulas. In the special case where a bound variable is Boolean and occurs on a side of an equality the other side cannot have a quantifier.
* Logical names for function declarations in c++
Currently, for example, the function declaration symbol member for
checking whether multiplication *does not* overflow is called
`m_bv_smul_ovfl`. Since we are introducing the upcoming smtlib2 symbols
that check that multpliciation *does* overflow, the not overflow check
symbols are renamed to `m_bv_smul_no_ovfl` etc.
* Implement smtlib overflow preds for multiplication
Smtlib2 is being extended to include overflow predicates for bit
vectors (see https://groups.google.com/u/1/g/smt-lib/c/J4D99wT0aKI).
This commit introduces the predicates `bvumulo` and `bvsmulo` that
return `true` if the unsigned multiplication overflows or the signed
multiplication underflows or overflows, respectively.
* Move mul overflow predicates to BV logic
* Add a todo on illogical argument order
* Implement mk_unary_pred for bv
* Implement bvnego
* Implement bvuaddo
* Implement bvsaddo
* Implement bvusubo
* Implement bvssubo
* Implement bvsdivo
deals with fluke regression for F* reported by Guido Martinez
Background:
The automatic pattern inference facility looks for terms that contains all bound variables of a quantifier. It may end up with a term that contains all bound variables but the extracted term can be simplified.
Example. The pattern
(ApplyTT (ApplyTT @x3!1 (ApplyTT @x4!0 (:var 1))) (ApplyTT @x4!0 (:var 0)))
can be decomposed into a multi-pattern
(ApplyTT @x4!0 (:var 1))) (ApplyTT @x4!0 (:var 0))
The multi-pattern may enable a quantifier instantiation while the original pattern does not. The multi-pattern should be preferred.
The regression showed up based on a change that should not be considered harmful but turned out to be noticeable.
The change was a simplification of and-or expressions based on sorting. This played with the case split queue used by F* (smt.case_split = 3) that uses a top-level case split of clauses to avoid redundant branches. The net effect was that without sorting, the benchmarks would always choose the opportune branch that enabled matching against the larger term. With sorting it would mostly choose inopportune branches.
- add option pp.no_lets (default = false) to print formulas without let (used by the low-level SMT2 printer).
- print lemmas2console faster by using the low level printer
- enforce elim-and in bool-rewriter when invoking hoisting.
- make cnf tactic more resilient to non-normalized input.
- enable eliminate predicates on ground formulas
