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experimental tweaks to RE rewriter to improve performance

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calebstanford-msr 2020-06-02 18:25:55 -04:00
parent 9987adbe20
commit e2a10e2615
2 changed files with 35 additions and 6 deletions
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39
src/ast/rewriter/seq_rewriter.cpp
View file

@ -703,9 +703,9 @@ br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * con
case _OP_STRING_STRIDOF:
UNREACHABLE();
}
if (st == BR_FAILED) {
st = lift_ite(f, num_args, args, result);
}
// if (st == BR_FAILED) {
// st = lift_ite(f, num_args, args, result);
// }
CTRACE("seq_verbose", st != BR_FAILED, tout << expr_ref(m().mk_app(f, num_args, args), m()) << " -> " << result << "\n";);
SASSERT(st == BR_FAILED || m().get_sort(result) == f->get_range());
return st;
@ -2315,7 +2315,7 @@ br_status seq_rewriter::mk_re_derivative(expr* ele, expr* r, expr_ref& result) {
return BR_REWRITE3;
}
else {
result = re().mk_union(result, re_and(is_n, dr2));
result = m().mk_ite(is_n, re().mk_union(result, dr2), result);
return BR_REWRITE3;
}
}
@ -2838,6 +2838,23 @@ br_status seq_rewriter::mk_str_to_regexp(expr* a, expr_ref& result) {
return BR_FAILED;
}
/*
easy cases:
.* ++ .* -> .*
[] ++ r -> []
r ++ [] -> []
r ++ "" -> r
"" ++ r -> r
to_re and star:
(str.to_re s1) ++ (str.to_re s2) -> (str.to_re (s1 ++ s2))
r* ++ r* -> r*
r* ++ r -> r ++ r*
if-then-else lifting:
r ++ (ite p r1 r2) -> ite(p (r ++ r1) (r ++ r2))
(ite p r1 r2) ++ r -> ite(p (r1 ++ r) (r2 ++ r))
*/
br_status seq_rewriter::mk_re_concat(expr* a, expr* b, expr_ref& result) {
if (re().is_full_seq(a) && re().is_full_seq(b)) {
result = a;
@ -2859,7 +2876,7 @@ br_status seq_rewriter::mk_re_concat(expr* a, expr* b, expr_ref& result) {
result = a;
return BR_DONE;
}
expr* a1 = nullptr, *b1 = nullptr;
expr *a1 = nullptr, *b1 = nullptr;
if (re().is_to_re(a, a1) && re().is_to_re(b, b1)) {
result = re().mk_to_re(str().mk_concat(a1, b1));
return BR_REWRITE2;
@ -2872,8 +2889,18 @@ br_status seq_rewriter::mk_re_concat(expr* a, expr* b, expr_ref& result) {
result = re().mk_concat(b, a);
return BR_DONE;
}
expr *a2 = nullptr, *b2 = nullptr, *cond = nullptr;
if (m().is_ite(a, cond, a1, a2)) {
result = m().mk_ite(cond, re().mk_concat(a1, b),
re().mk_concat(a2, b));
return BR_REWRITE2;
}
if (m().is_ite(b, cond, b1, b2)) {
result = m().mk_ite(cond, re().mk_concat(a, b1),
re().mk_concat(a, b2));
return BR_REWRITE2;
}
unsigned lo1, hi1, lo2, hi2;
if (re().is_loop(a, a1, lo1, hi1) && lo1 <= hi1 && re().is_loop(b, b1, lo2, hi2) && lo2 <= hi2 && a1 == b1) {
result = re().mk_loop(a1, lo1 + lo2, hi1 + hi2);
return BR_DONE;

2
src/smt/seq_regex.cpp
View file

@ -197,6 +197,8 @@ namespace smt {
TRACE("seq", tout << "propagate " << mk_pp(e, m) << "\n";);
// std::cout << "SEQ REGEX PROPOGATE: " << mk_pp(e, m) << std::endl;
if (block_unfolding(lit, idx))
return true;