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add rewrite rule

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This commit is contained in:
Nikolaj Bjorner 2020-12-07 21:28:23 -08:00
parent 430b4ea252
commit f5f980fa38
1 changed files with 8 additions and 0 deletions
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8
src/ast/rewriter/seq_rewriter.cpp
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@ -1428,6 +1428,7 @@ br_status seq_rewriter::mk_seq_last_index(expr* a, expr* b, expr_ref& result) {
indexof("", b, r) -> if b = "" and r = 0 then 0 else -1 indexof("", b, r) -> if b = "" and r = 0 then 0 else -1
indexof(unit(x)+a, b, r+1) -> indexof(a, b, r) indexof(unit(x)+a, b, r+1) -> indexof(a, b, r)
indexof(unit(x)+a, unit(y)+b, 0) -> indexof(a,unit(y)+b, 0) if x != y indexof(unit(x)+a, unit(y)+b, 0) -> indexof(a,unit(y)+b, 0) if x != y
indexof(substr(x,y,len1), z, len2) -> -1 if len2 > len1
*/ */
br_status seq_rewriter::mk_seq_index(expr* a, expr* b, expr* c, expr_ref& result) { br_status seq_rewriter::mk_seq_index(expr* a, expr* b, expr* c, expr_ref& result) {
zstring s1, s2; zstring s1, s2;
@ -1468,6 +1469,13 @@ br_status seq_rewriter::mk_seq_index(expr* a, expr* b, expr* c, expr_ref& result
return BR_REWRITE2; return BR_REWRITE2;
} }
} }
expr* x = nullptr, *y = nullptr, *len1 = nullptr;
rational r1, r2;
if (str().is_extract(a, x, y, len1) && m_autil.is_numeral(len1, r1) &&
m_autil.is_numeral(c, r2) && r2 > r1) {
result = minus_one();
return BR_DONE;
}
expr_ref_vector as(m()), bs(m()); expr_ref_vector as(m()), bs(m());
str().get_concat_units(a, as); str().get_concat_units(a, as);