the solve_eqs_tactic is to be replaced by a re-implementation that uses solve_eqs in the simplifiers directory.
The re-implementation should address efficiency issues with the previous code.
At this point it punts on low level proofs. The plan is to use coarser
dependency tracking instead of low level proofs for pre-processing. Dependencies can be converted into a proof hint representation that can be checked using a stronger checker.
* Memory leak in .NET user-propagator
The user-propagator object has to be manually disposed (IDisposable), otherwise it stays in memory forever, as it cannot be garbage collected automatically
* Throw an exception if variable passed to decide is already assigned instead of running in an assertion violation
* Added limit to "visit" to allow detecting multiple visits
* Putting visit in a separate class
(Reason: We will probably need two of them in the sat::solver)
* Bugfix
* Memory leak in .NET user-propagator
The user-propagator object has to be manually disposed (IDisposable), otherwise it stays in memory forever, as it cannot be garbage collected automatically
* Throw an exception if variable passed to decide is already assigned instead of running in an assertion violation
* Added 64-bit "1" counting
simplifiers layer is a common substrate for global non-incremental and incremental processing.
The first two layers are new, but others are to be ported form tactics.
- bv::slice - rewrites equations to cut-dice-slice bit-vector extractions until they align. It creates opportunities for rewriting portions of bit-vectors to common sub-expressions, including values.
- euf::completion - generalizes the KB simplifcation from asserted formulas to use the E-graph to establish a global and order-independent canonization.
The interface dependent_expr_simplifier is amenable to forming tactics. Plugins for asserted-formulas is also possible but not yet realized.
- ensure mk_extract performs simplification to distribute over extract and removing extract if the range is the entire bit-vector
- ensure bool_rewriter simplifeis disjunctions when applicable.
Removing ternary clause optimization from sat_solver simplifies special case handling of ternary clauses throughout the sat solver and dependent solvers (pb_solver). Benchmarking on QF_BV suggests the ternary clause optimization does not have any effect. While removing ternary clause optimization two bugs in unit propagation were also uncovered: it missed propagations when the only a single undef literal remained in the non-watched literals and it did not update blocked literals in cases where it could in the watch list. These performance bugs were for general clauses, ternary clause propagation did not miss propagations (and don't use blocked literals), but fixing these issues for general clauses appear to have made ternary clause optimization irrelevant based on what was measured.
