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fix re.range rewrite for theory_str

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This commit is contained in:
Murphy Berzish 2017-03-10 13:13:45 -05:00
parent 4d5c1dcfb6
commit c198bc5863
2 changed files with 39 additions and 4 deletions
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42
src/ast/rewriter/seq_rewriter.cpp
View file

@ -350,7 +350,8 @@ br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * con
SASSERT(num_args == 2);
return mk_re_union(args[0], args[1], result);
case OP_RE_RANGE:
return BR_FAILED;
SASSERT(num_args == 2);
return mk_re_range(args[0], args[1], result);
case OP_RE_INTERSECT:
SASSERT(num_args == 2);
return mk_re_inter(args[0], args[1], result);
@ -1313,6 +1314,39 @@ br_status seq_rewriter::mk_re_star(expr* a, expr_ref& result) {
return BR_FAILED;
}
/*
* (re.range c_1 c_n) = (re.union (str.to.re c1) (str.to.re c2) ... (str.to.re cn))
*/
br_status seq_rewriter::mk_re_range(expr* lo, expr* hi, expr_ref& result) {
TRACE("seq", tout << "rewrite re.range [" << mk_pp(lo, m()) << " " << mk_pp(hi, m()) << "]\n";);
zstring str_lo, str_hi;
if (m_util.str.is_string(lo, str_lo) && m_util.str.is_string(hi, str_hi)) {
if (str_lo.length() == 1 && str_hi.length() == 1) {
unsigned int c1 = str_lo[0];
unsigned int c2 = str_hi[0];
if (c1 > c2) {
// exchange c1 and c2
unsigned int tmp = c1;
c2 = c1;
c1 = tmp;
}
zstring s(c1);
expr_ref acc(m_util.re.mk_to_re(m_util.str.mk_string(s)), m());
for (unsigned int ch = c1 + 1; ch <= c2; ++ch) {
zstring s_ch(ch);
expr_ref acc2(m_util.re.mk_to_re(m_util.str.mk_string(s_ch)), m());
acc = m_util.re.mk_union(acc, acc2);
}
result = acc;
return BR_REWRITE2;
} else {
m().raise_exception("string constants in re.range must have length 1");
}
}
return BR_FAILED;
}
/*
emp+ = emp
all+ = all
@ -1342,9 +1376,9 @@ br_status seq_rewriter::mk_re_plus(expr* a, expr_ref& result) {
return BR_DONE;
}
return BR_FAILED;
// result = m_util.re.mk_concat(a, m_util.re.mk_star(a));
// return BR_REWRITE2;
//return BR_FAILED;
result = m_util.re.mk_concat(a, m_util.re.mk_star(a));
return BR_REWRITE2;
}
br_status seq_rewriter::mk_re_opt(expr* a, expr_ref& result) {

1
src/ast/rewriter/seq_rewriter.h
View file

@ -120,6 +120,7 @@ class seq_rewriter {
br_status mk_re_plus(expr* a, expr_ref& result);
br_status mk_re_opt(expr* a, expr_ref& result);
br_status mk_re_loop(unsigned num_args, expr* const* args, expr_ref& result);
br_status mk_re_range(expr* lo, expr* hi, expr_ref& result);
bool set_empty(unsigned sz, expr* const* es, bool all, expr_ref_vector& lhs, expr_ref_vector& rhs);
bool is_subsequence(unsigned n, expr* const* l, unsigned m, expr* const* r,