observed perf overhead for QF_NIA is that assume_eqs in theory_lra incurs significant overhead when calling is_relevant_and_shared. The call to context::is_shared and the loop checking for beta redexes is a main bottleneck. The bottleneck is avoided by caching the result if is_shared inside the enode. It is invalidated for every merge/unmerge.
* qe_lite: cleanup and comment
no change to code
* mbp_arrays: refactor out partial equality (peq)
Partial array equality, PEQ, is used as an intermediate
expression during MBP for arrays. We need to factor it out
so that it can be shared between MBP-QEL and existing MBP.
Partial array equality (peq) is used in MBP for arrays.
Factoring this out to be used by multiple MBP implementations.
* rewriter: new rewrite rules
These rules are specializes for terms that are created in QEL.
QEL commit is comming later
* datatype_rw: new rewrite rule for ADTs
The rule handles this special case:
(cons (head x) (tail x)) --> x
* array_rewriter rules for rewriting PEQs
Special rules to simplify PEQs
* th_rewriter: wire PEQ simplifications
* spacer_iuc: avoid terms with default in IUC
Spacer prfers to not have a term representing default value of an array.
This guides IUC from picking such terms in interpolation
* mbp_term_graph: replace root with repr
* mbp_term_graph: formatting
* mbp_term_graph: class_props, getters, setters
Class properties allow to keep information for an equivalence class.
Getters and setters for terms allow accessing information
* mbp_term_graph: auxiliary methods for qel
QEL commit is comming later in the history
* mbp_term_graph: bug fix
* mbp_term_graph: pick, refine repr, compute cgrnd
* mbp_term_graph: internalize deq
* mbp_term_graph: constructor
* mbp_term_graph: optionally internalize equalities
Reperesent equalities explicitly by nodes in the term_graph
* qel
* formatting
* comments on term_lt
* get terms and other api for mbp_qel
* plugins for mbp_qel
* mbp_qel_util: utilities for mbp_qel
* qe_mbp: QEL-based mbp
* qel: expose QEL API
* spacer: replace qe_lite in qe_project_spacer by qel
This changes the default projection engine that spacer uses.
* cmd_context: debug commands for qel and mbp_qel
New commands are
mbp-qel -- MBP with term graphs
qel -- QEL with term graphs
qe-lite -- older qelite
* qe_mbp: model-based rewriters for arrays
* qe_mbp: QEL-based projection functions
* qsat: wire in QEL-based mbp
* qsat: debug code
* qsat: maybe a bug fix
Changed the code to follow the paper by adding all predicates above a given
level, not just predicates of immediately preceding level.
* chore: use new api to create solver in qsat
* mbp_term_graph use all_of idiom
* feat: solver for integer multiplication
* array_peq: formatting, no change to code
* mbp_qel_util: block comment + format
* mbt_term_graph: clang-format
* bug fix. Move dt rewrite to qe_mbp
* array_peq: add header
* run clang format on mbp plugins
* clang format on mul solver
* format do-while
* format
* format do-while
* update release notes
---------
Co-authored-by: hgvk94 <hgvk94@gmail.com>
Co-authored-by: Isabel Garcia <igarciac@uwaterloo.ca>
An initial update to support polymorphism from SMTLIB3 and the API (so far C, Python).
The WIP SMTLIB3 format is assumed to be supporting the following declaration
```
(declare-type-var A)
```
Whenever A is used in a type signature of a function/constant or bound quantified variable, it is taken to mean that all instantiations of A are included in the signature and assertions.
For example, if the function f is declared with signature A -> A, then there is a version of f for all instances of A.
The semantics of polymorphism appears to follow previous proposals: the instances are effectively different functions.
This may clash with some other notions, such as the type signature forall 'a . 'a -> 'a would be inhabited by a unique function (the identity), while this is not enforced in this version (and hopefully never because it is more busy work).
The C API has the function 'Z3_mk_type_variable' to create a type variable and applying functions modulo polymorphic type signatures is possible.
The kind Z3_TYPE_VAR is added to sort discriminators.
This version is considered as early alpha. It passes a first rudimentary unit test involving quantified axioms, declare-fun, define-fun, and define-fun-rec.
After introducing the rewriter.sort_disjunctions option (#6774), I
noticed a segfault in a Z3 run that was working fine for me before the
PR.
I traced the difference to a slight discrepancy between the first patch
I submitted and the one we ended up merging: my first version would skip
sorting the disjuncts in mk_nflat_core, but still return BR_DONE, while
the patch in master returns BR_FAILED instead.
This patch fixes that problem, and it makes slightly more sense to me to
return a BR_DONE since, if `s` is true, some disjunct (e.g. a `false`
or a repeat) might have been simplified away. However I don't fully
understand this code.
... and I can't say I understand why the segfault happens. Perhaps that
is a separate issue?
This is the file to reproduce:
https://gist.github.com/mtzguido/b7360c74d3d2e42d89f1bd9149ad26f6
Here's a stack trace of the failure, mk_nflat_or_core is not involved.
```
(gdb) where
#0 0x0000555555b98497 in smt::context::get_lit_assignment(unsigned int) const ()
#1 0x0000555555b984cb in smt::context::get_assignment(sat::literal) const ()
#2 0x0000555555b98504 in smt::context::get_assignment(unsigned int) const ()
#3 0x0000555555ca83b8 in smt::context::get_assignment_core(expr*) const ()
#4 0x0000555555c9af5a in smt::context::get_assignment(expr*) const ()
#5 0x0000555555d7bd1d in (anonymous namespace)::has_child_assigned_to(smt::context&, app*, lbool, expr*&, unsigned int) ()
#6 0x0000555555d7c413 in (anonymous namespace)::rel_case_split_queue::next_case_split_core(ptr_vector<expr>&, unsigned int&, unsigned int&, lbool&) ()
#7 0x0000555555d7c589 in (anonymous namespace)::rel_case_split_queue::next_case_split(unsigned int&, lbool&) ()
#8 0x0000555555c9c1b7 in smt::context::decide() ()
#9 0x0000555555ca39fd in smt::context::bounded_search() ()
#10 0x0000555555ca30c2 in smt::context::search() ()
#11 0x0000555555ca273d in smt::context::check(unsigned int, expr* const*, bool) ()
#12 0x0000555555cb166a in smt::kernel::check(unsigned int, expr* const*) ()
#13 0x0000555555cb9695 in (anonymous namespace)::smt_solver::check_sat_core2(unsigned int, expr* const*) ()
#14 0x00005555560dc0c6 in solver_na2as::check_sat_core(unsigned int, expr* const*) ()
#15 0x00005555560d73f3 in combined_solver::check_sat_core(unsigned int, expr* const*) ()
#16 0x00005555560d34e3 in solver::check_sat(unsigned int, expr* const*) ()
#17 0x0000555556097b26 in cmd_context::check_sat(unsigned int, expr* const*) ()
#18 0x0000555556082ff0 in smt2::parser::parse_check_sat() ()
#19 0x0000555556084dc0 in smt2::parser::parse_cmd() ()
#20 0x00005555560861b6 in smt2::parser::operator()() ()
#21 0x00005555560757e6 in parse_smt2_commands(cmd_context&, std::basic_istream<char, std::char_traits<char> >&, bool, params_ref const&, char const*) ()
#22 0x00005555555e8f68 in read_smtlib2_commands(char const*) ()
#23 0x00005555555ee6f6 in main ()
(gdb)
```
* patterns: add option for pattern decomposition (pi.decompose_patterns)
True by default, retaining current behavior.
* rewriter: add option for sorting of disjunctions (rewriter.sort_disjunctions)
True by default, retaining current behavior.
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.
