- Simplify trivial range bounds in derive_range: when lo=0, omit
the lo<=x condition; when hi=max_char, omit the x<=hi condition.
Full charset ranges return epsilon directly.
- Add char_le(0,x)=true and char_le(x,max)=true to eval_cond for
always-valid bounds.
- Add range implication logic to simplify_ite_rec: when path has
negated/positive char_le constraints, detect implied or contradicted
char_le conditions (e.g., ¬(x<=127) implies 128<=x).
- Add is_subset(a, .+) check: non-nullable regexes are subsets of .+
- In update_state_graph, skip recursive exploration of nullable targets
to avoid state explosion.
These fixes resolve timeouts on 5724 (all problems), 5721 P1, and 5693.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Implements the algorithm of Eq(p,q) = Empty(p XOR q)' using a union-find
driven bisimulation closure (per the CAV'26 ERE paper).
### What's added
* **New primitive OP_RE_XOR (re.xor)** wired through seq_decl_plugin:
parser signature, info propagation (nullable, min_length), and
pretty-printer.
* **seq_rewriter**: structural XOR rewrites ( XOR r = empty, XOR empty =
r, ull XOR r = comp(r), comp/comp absorption, complement push, AC
normalisation), nullability (Null(p XOR q) = Null(p) != Null(q)),
derivative (D_a(p XOR q) = D_a(p) XOR D_a(q)), reverse, antimirov
derivative, and `check_deriv_normal_form` coverage.
* **New class seq::regex_bisim** in
`src/ast/rewriter/seq_regex_bisim.{h,cpp}` to keep the bisim logic out
of the already-large `seq_rewriter.cpp`. Uses `basic_union_find` from
`util/union_find.h`, an `obj_map` for the node assignment, and a
50000-step bound (returns `l_undef` on overrun).
* **Integration** in `seq_rewriter::reduce_re_eq` (with a re-entry
guard) and in `seq_regex::propagate_eq` / `propagate_ne` for ground
regexes; on `l_undef` we fall back to the existing axiomatisation.
* **`sls_seq_plugin`**: extend `OP_RE_DIFF` switch arms to also cover
`OP_RE_XOR`.
### Validation
* Full release build with MSVC + Ninja.
* `./test-z3 /a` -- 89/89 tests passing.
* `./test-z3 /seq smt2print_parse` -- PASS.
* Smoke tests with `(a|b)*` vs `(a*b*)*` (equal) and `a*` vs `(a|b)*`
(not equal) return the expected `sat`/`unsat` quickly.
---------
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
* Introduce X-macro-based trace tag definition
- Created trace_tags.def to centralize TRACE tag definitions
- Each tag includes a symbolic name and description
- Set up enum class TraceTag for type-safe usage in TRACE macros
* Add script to generate Markdown documentation from trace_tags.def
- Python script parses trace_tags.def and outputs trace_tags.md
* Refactor TRACE_NEW to prepend TraceTag and pass enum to is_trace_enabled
* trace: improve trace tag handling system with hierarchical tagging
- Introduce hierarchical tag-class structure: enabling a tag class activates all child tags
- Unify TRACE, STRACE, SCTRACE, and CTRACE under enum TraceTag
- Implement initial version of trace_tag.def using X(tag, tag_class, description)
(class names and descriptions to be refined in a future update)
* trace: replace all string-based TRACE tags with enum TraceTag
- Migrated all TRACE, STRACE, SCTRACE, and CTRACE macros to use enum TraceTag values instead of raw string literals
* trace : add cstring header
* trace : Add Markdown documentation generation from trace_tags.def via mk_api_doc.py
* trace : rename macro parameter 'class' to 'tag_class' and remove Unicode comment in trace_tags.h.
* trace : Add TODO comment for future implementation of tag_class activation
* trace : Disable code related to tag_class until implementation is ready (#7663).
* std::cout debugging statements
* comment out std::cout debugging as this is now a shared fork
* convert std::cout to TRACE statements for seq_rewriter and seq_regex
* add cases to min_length and max_length for regexes
* bug fix
* update min_length and max_length functions for REs
* initial pass on simplifying derivative normal forms by eliminating redundant predicates locally
* add seq_regex_brief trace statements
* working on debugging ref count issue
* fix ref count bug and convert trace statements to seq_regex_brief
* add compact tracing for cache hits/misses
* seq_regex fix cache hit/miss tracing and wrapper around is_nullable
* minor
* label and disable more experimental changes for testing
* minor documentation / tracing
* a few more @EXP annotations
* dead state elimination skeleton code
* progress on dead state elimination
* more progress on dead state elimination
* refactor dead state class to separate self-contained state_graph class
* finish factoring state_graph to only work with unsigned values, and implement separate functionality for expr* logic
* implement get_all_derivatives, add debug tracing
* trace statements for debugging is_nullable loop bug
* fix is_nullable loop bug
* comment out local nullable change and mark experimental
* pretty printing for state_graph
* rewrite state graph to remove the fragile assumption that all edges from a state are added at a time
* start of general cycle detection check + fix some comments
* implement full cycle detection procedure
* normalize derivative conditions to form 'ele <= a'
* order derivative conditions by character code
* fix confusing names m_to and m_from
* assign increasing state IDs from 1 instead of using get_id on AST node
* remove elim_condition call in get_dall_derivatives
* use u_map instead of uint_map to avoid memory leak
* remove unnecessary call to is_ground
* debugging
* small improvements to seq_regex_brief tracing
* fix bug on evil2 example
* save work
* new propagate code
* work in progress on using same seq sort for deriv calls
* avoid re-computing derivatives: use same head var for every derivative call
* use min_length on regexes to prune search
* simple implementation of can_be_in_cycle using rank function idea
* add a disabled experimental change
* minor cleanup comments, etc.
* seq_rewriter cleanup for PR
* typo noticed by Nikolaj
* move state graph to util/state_graph
* re-add accidentally removed line
* clean up seq_regex code removing obsolete functions and comments
* a few more cleanup items
* oops, missed merge change to fix compilation
* disabled change to lift unions to the top level and treat them seperately in seq_regex solver
* added get_overapprox_regex to over-approximate regex membership constraints
* replace calls to is_epsilon with a centrally available method in seq_decl_plugin
* simplifications and modifications in get_overapprox_regex and related
* added approximation support for sequence expressions that use ite
* removed is_app check that was redundant
* tweak differences with upstream
* rewrite derivative leaves
* enable Antimorov-style derivatives via lifting unions in the solver
* TODO placeholders for outputting state graph
* change order in seq_regex propagate_in_re
* implement a more restricted form of Antimorov derivatives via a special op code to indicate lifting unions
* minor
* new Antimorov optimizations based on BDD compatibility checking
* seq regex tracing for # of derivatives
* fix get_cofactors (currently this fix is buggy)
* partially revert get_cofactors buggy change
* re-implement get_cofactors to more efficiently explore nodes in the derivative expression
* dgml generation for state graph
* fix release build
* improved dgml output
* bug fixes in dgml generation
* dot output support for state_graph and moved dgml and dot output under CASSERT
* updated tracing of what regex corresponds to what state id with /tr:state_graph
* clean up & document Antimorov derivative support
* remove op cache tracing
* remove re_rank experimental idea
* small fix
* fix Antimorov derivative (important change for the good performance)
* remove unused and unnecessary code
* implemented simpler efficient get_cofactors alternative mk_deriv_accept
* simplifications in propagate_accept, and trace unusual cases
* document the various seq_regex tracing & debugging command-line options
* fix debug build (broken tracing)
* guard eager Antimorov lifting for possible disabling
* fix bug in propagate_accept Rule 1
* disable eager version of Antimorov lifting for performance reasons
* remove some remaining obsolete comments
Co-authored-by: calebstanford-msr <t-casta@microsoft.com>
Co-authored-by: Margus Veanes <margus@microsoft.com>
* std::cout debugging statements
* comment out std::cout debugging as this is now a shared fork
* convert std::cout to TRACE statements for seq_rewriter and seq_regex
* add cases to min_length and max_length for regexes
* bug fix
* update min_length and max_length functions for REs
* initial pass on simplifying derivative normal forms by eliminating redundant predicates locally
* add seq_regex_brief trace statements
* working on debugging ref count issue
* fix ref count bug and convert trace statements to seq_regex_brief
* add compact tracing for cache hits/misses
* seq_regex fix cache hit/miss tracing and wrapper around is_nullable
* minor
* label and disable more experimental changes for testing
* minor documentation / tracing
* a few more @EXP annotations
* dead state elimination skeleton code
* progress on dead state elimination
* more progress on dead state elimination
* refactor dead state class to separate self-contained state_graph class
* finish factoring state_graph to only work with unsigned values, and implement separate functionality for expr* logic
* implement get_all_derivatives, add debug tracing
* trace statements for debugging is_nullable loop bug
* fix is_nullable loop bug
* comment out local nullable change and mark experimental
* pretty printing for state_graph
* rewrite state graph to remove the fragile assumption that all edges from a state are added at a time
* start of general cycle detection check + fix some comments
* implement full cycle detection procedure
* normalize derivative conditions to form 'ele <= a'
* order derivative conditions by character code
* fix confusing names m_to and m_from
* assign increasing state IDs from 1 instead of using get_id on AST node
* remove elim_condition call in get_dall_derivatives
* use u_map instead of uint_map to avoid memory leak
* remove unnecessary call to is_ground
* debugging
* small improvements to seq_regex_brief tracing
* fix bug on evil2 example
* save work
* new propagate code
* work in progress on using same seq sort for deriv calls
* avoid re-computing derivatives: use same head var for every derivative call
* use min_length on regexes to prune search
* simple implementation of can_be_in_cycle using rank function idea
* add a disabled experimental change
* minor cleanup comments, etc.
* seq_rewriter cleanup for PR
* typo noticed by Nikolaj
* move state graph to util/state_graph
* re-add accidentally removed line
* clean up seq_regex code removing obsolete functions and comments
* a few more cleanup items
* remove experimental functionality for integration
* fix compilation
* remove some tracing and TODOs
* remove old comment
* update copyright dates to 2020
* feedback from Nikolaj
* use [] for map access
* make state_graph methods constant
* avoid recursion in mark_dead_recursive and mark_live_recursive
* a possible bug fix in propagate_nonempty
* write down list of invariants in state_graph
* implement partial invariant check and insert CASSERT statements
* expand on invariant check and tracing
* finish state graph invariant check
* minor tweaks
* regex propagation: convert first two axioms to propagations
* remove obsolete regex solver functionality
Co-authored-by: calebstanford-msr <t-casta@microsoft.com>
* remove unneeded reverse case in derivative; placeholder for generalized lifted derivative
* experimental tweaks to RE rewriter to improve performance
* if-then-else lifting
(broken code -- preserving this commit in case this idea is useful later)
* if-then-else derivative optimizations: new approach templates
* implement if-then-else BDD normal form for derivatives
(code compiles but is still buggy)
* remove std::cout debugging for PR
* Revert "remove std::cout debugging for PR"
This reverts commit c7bdc44d31.
* debugging
* fix derivative interaction with reverse; add flags for left/right derivative and lifting over union/intersection
* remove debugging statements for PR
* Revert "remove debugging statements for PR"
This reverts commit 38e85a7288.
* revert some purely cosmetic changes from upstream; fix a bug
* revert unnecessary changes
* remove some redundant rewrites and add a new one for str.in_re(s, comp(r))
* add disabled rewrite for complement
* fix bug in op cache find (result was not saved)
* remove debugging std::cout for PR
