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Merge remote-tracking branch 'upstream/master' into HEAD

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This commit is contained in:
Murphy Berzish 2017-10-30 13:55:31 -04:00
commit a8d025f5b4
1661 changed files with 45439 additions and 28238 deletions
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177
src/smt/theory_str.cpp
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@ -189,17 +189,18 @@ namespace smt {
m_trail.push_back(e);
//TRACE("str", tout << "done asserting " << mk_ismt2_pp(e, get_manager()) << std::endl;);
}
expr * theory_str::rewrite_implication(expr * premise, expr * conclusion) {
ast_manager & m = get_manager();
return m.mk_or(m.mk_not(premise), conclusion);
return m.mk_or(mk_not(m, premise), conclusion);
}
void theory_str::assert_implication(expr * premise, expr * conclusion) {
ast_manager & m = get_manager();
TRACE("str", tout << "asserting implication " << mk_ismt2_pp(premise, m) << " -> " << mk_ismt2_pp(conclusion, m) << std::endl;);
expr_ref axiom(m.mk_or(m.mk_not(premise), conclusion), m);
expr_ref axiom(m.mk_or(mk_not(m, premise), conclusion), m);
assert_axiom(axiom);
}
@ -318,6 +319,7 @@ namespace smt {
m_trail.push_back(node);
if (!cut_var_map.contains(baseNode)) {
T_cut * varInfo = alloc(T_cut);
m_cut_allocs.push_back(varInfo);
varInfo->level = slevel;
varInfo->vars[node] = 1;
cut_var_map.insert(baseNode, std::stack<T_cut*>());
@ -326,6 +328,7 @@ namespace smt {
} else {
if (cut_var_map[baseNode].empty()) {
T_cut * varInfo = alloc(T_cut);
m_cut_allocs.push_back(varInfo);
varInfo->level = slevel;
varInfo->vars[node] = 1;
cut_var_map[baseNode].push(varInfo);
@ -333,6 +336,7 @@ namespace smt {
} else {
if (cut_var_map[baseNode].top()->level < slevel) {
T_cut * varInfo = alloc(T_cut);
m_cut_allocs.push_back(varInfo);
varInfo->level = slevel;
cut_vars_map_copy(varInfo->vars, cut_var_map[baseNode].top()->vars);
varInfo->vars[node] = 1;
@ -362,6 +366,7 @@ namespace smt {
if (!cut_var_map.contains(destNode)) {
T_cut * varInfo = alloc(T_cut);
m_cut_allocs.push_back(varInfo);
varInfo->level = slevel;
cut_vars_map_copy(varInfo->vars, cut_var_map[srcNode].top()->vars);
cut_var_map.insert(destNode, std::stack<T_cut*>());
@ -370,6 +375,7 @@ namespace smt {
} else {
if (cut_var_map[destNode].empty() || cut_var_map[destNode].top()->level < slevel) {
T_cut * varInfo = alloc(T_cut);
m_cut_allocs.push_back(varInfo);
varInfo->level = slevel;
cut_vars_map_copy(varInfo->vars, cut_var_map[destNode].top()->vars);
cut_vars_map_copy(varInfo->vars, cut_var_map[srcNode].top()->vars);
@ -543,7 +549,7 @@ namespace smt {
context & ctx = get_context();
ast_manager & m = get_manager();
expr_ref ax1(m.mk_not(ctx.mk_eq_atom(s, mk_string(""))), m);
expr_ref ax1(mk_not(m, ctx.mk_eq_atom(s, mk_string(""))), m);
assert_axiom(ax1);
{
@ -555,7 +561,7 @@ namespace smt {
SASSERT(zero);
// build LHS > RHS and assert
// we have to build !(LHS <= RHS) instead
expr_ref lhs_gt_rhs(m.mk_not(m_autil.mk_le(len_str, zero)), m);
expr_ref lhs_gt_rhs(mk_not(m, m_autil.mk_le(len_str, zero)), m);
SASSERT(lhs_gt_rhs);
assert_axiom(lhs_gt_rhs);
}
@ -590,7 +596,7 @@ namespace smt {
SASSERT(zero);
// build LHS > RHS and assert
// we have to build !(LHS <= RHS) instead
expr_ref lhs_gt_rhs(m.mk_not(m_autil.mk_le(len_str, zero)), m);
expr_ref lhs_gt_rhs(mk_not(m, m_autil.mk_le(len_str, zero)), m);
SASSERT(lhs_gt_rhs);
assert_axiom(lhs_gt_rhs);
}
@ -1087,7 +1093,7 @@ namespace smt {
m_autil.mk_ge(expr->get_arg(1), mk_int(0)),
// REWRITE for arithmetic theory:
// m_autil.mk_lt(expr->get_arg(1), mk_strlen(expr->get_arg(0)))
m.mk_not(m_autil.mk_ge(m_autil.mk_add(expr->get_arg(1), m_autil.mk_mul(mk_int(-1), mk_strlen(expr->get_arg(0)))), mk_int(0)))
mk_not(m, m_autil.mk_ge(m_autil.mk_add(expr->get_arg(1), m_autil.mk_mul(mk_int(-1), mk_strlen(expr->get_arg(0)))), mk_int(0)))
), m);
expr_ref_vector and_item(m);
@ -1128,7 +1134,7 @@ namespace smt {
expr_ref_vector innerItems(m);
innerItems.push_back(ctx.mk_eq_atom(expr->get_arg(1), mk_concat(ts0, ts1)));
innerItems.push_back(ctx.mk_eq_atom(mk_strlen(ts0), mk_strlen(expr->get_arg(0))));
innerItems.push_back(m.mk_ite(ctx.mk_eq_atom(ts0, expr->get_arg(0)), expr, m.mk_not(expr)));
innerItems.push_back(m.mk_ite(ctx.mk_eq_atom(ts0, expr->get_arg(0)), expr, mk_not(m, expr)));
expr_ref then1(m.mk_and(innerItems.size(), innerItems.c_ptr()), m);
SASSERT(then1);
@ -1141,7 +1147,7 @@ namespace smt {
, m);
SASSERT(topLevelCond);
expr_ref finalAxiom(m.mk_ite(topLevelCond, then1, m.mk_not(expr)), m);
expr_ref finalAxiom(m.mk_ite(topLevelCond, then1, mk_not(m, expr)), m);
SASSERT(finalAxiom);
assert_axiom(finalAxiom);
}
@ -1165,7 +1171,7 @@ namespace smt {
expr_ref_vector innerItems(m);
innerItems.push_back(ctx.mk_eq_atom(expr->get_arg(1), mk_concat(ts0, ts1)));
innerItems.push_back(ctx.mk_eq_atom(mk_strlen(ts1), mk_strlen(expr->get_arg(0))));
innerItems.push_back(m.mk_ite(ctx.mk_eq_atom(ts1, expr->get_arg(0)), expr, m.mk_not(expr)));
innerItems.push_back(m.mk_ite(ctx.mk_eq_atom(ts1, expr->get_arg(0)), expr, mk_not(m, expr)));
expr_ref then1(m.mk_and(innerItems.size(), innerItems.c_ptr()), m);
SASSERT(then1);
@ -1178,7 +1184,7 @@ namespace smt {
, m);
SASSERT(topLevelCond);
expr_ref finalAxiom(m.mk_ite(topLevelCond, then1, m.mk_not(expr)), m);
expr_ref finalAxiom(m.mk_ite(topLevelCond, then1, mk_not(m, expr)), m);
SASSERT(finalAxiom);
assert_axiom(finalAxiom);
}
@ -1202,7 +1208,7 @@ namespace smt {
if (haystackStr.contains(needleStr)) {
assert_axiom(ex);
} else {
assert_axiom(m.mk_not(ex));
assert_axiom(mk_not(m, ex));
}
return;
}
@ -1263,7 +1269,7 @@ namespace smt {
SASSERT(tmpLen);
thenItems.push_back(ctx.mk_eq_atom(expr->get_arg(0), mk_concat(x3, x4)));
thenItems.push_back(ctx.mk_eq_atom(mk_strlen(x3), tmpLen));
thenItems.push_back(m.mk_not(mk_contains(x3, expr->get_arg(1))));
thenItems.push_back(mk_not(m, mk_contains(x3, expr->get_arg(1))));
expr_ref thenBranch(m.mk_and(thenItems.size(), thenItems.c_ptr()), m);
SASSERT(thenBranch);
@ -1339,7 +1345,7 @@ namespace smt {
expr_ref ite1(m.mk_ite(
//m_autil.mk_lt(expr->get_arg(2), zeroAst),
m.mk_not(m_autil.mk_ge(expr->get_arg(2), zeroAst)),
mk_not(m, m_autil.mk_ge(expr->get_arg(2), zeroAst)),
ctx.mk_eq_atom(resAst, mk_indexof(expr->get_arg(0), expr->get_arg(1))),
ite2
), m);
@ -1382,7 +1388,7 @@ namespace smt {
thenItems.push_back(m_autil.mk_ge(indexAst, mk_int(0)));
// args[0] = x1 . args[1] . x2
// x1 doesn't contain args[1]
thenItems.push_back(m.mk_not(mk_contains(x2, expr->get_arg(1))));
thenItems.push_back(mk_not(m, mk_contains(x2, expr->get_arg(1))));
thenItems.push_back(ctx.mk_eq_atom(indexAst, mk_strlen(x1)));
bool canSkip = false;
@ -1400,7 +1406,7 @@ namespace smt {
expr_ref tmpLen(m_autil.mk_add(indexAst, mk_int(1)), m);
thenItems.push_back(ctx.mk_eq_atom(expr->get_arg(0), mk_concat(x3, x4)));
thenItems.push_back(ctx.mk_eq_atom(mk_strlen(x3), tmpLen));
thenItems.push_back(m.mk_not(mk_contains(x4, expr->get_arg(1))));
thenItems.push_back(mk_not(m, mk_contains(x4, expr->get_arg(1))));
}
//----------------------------
// else branch
@ -1448,9 +1454,10 @@ namespace smt {
argumentsValid_terms.push_back(m_autil.mk_ge(substrPos, zero));
// pos < strlen(base)
// --> pos + -1*strlen(base) < 0
argumentsValid_terms.push_back(m.mk_not(m_autil.mk_ge(
argumentsValid_terms.push_back(mk_not(m, m_autil.mk_ge(
m_autil.mk_add(substrPos, m_autil.mk_mul(minusOne, substrLen)),
zero)));
// len >= 0
argumentsValid_terms.push_back(m_autil.mk_ge(substrLen, zero));
@ -1480,6 +1487,7 @@ namespace smt {
// Case 3: (pos >= 0 and pos < strlen(base) and len >= 0) and (pos+len) < strlen(base)
// ==> base = t2.t3.t4 AND len(t2) = pos AND len(t3) = len AND (Substr ...) = t3
expr_ref t2(mk_str_var("t2"), m);
expr_ref t3(mk_str_var("t3"), m);
expr_ref t4(mk_str_var("t4"), m);
@ -1541,7 +1549,7 @@ namespace smt {
expr_ref tmpLen(m_autil.mk_add(i1, mk_strlen(expr->get_arg(1)), mk_int(-1)), m);
thenItems.push_back(ctx.mk_eq_atom(expr->get_arg(0), mk_concat(x3, x4)));
thenItems.push_back(ctx.mk_eq_atom(mk_strlen(x3), tmpLen));
thenItems.push_back(m.mk_not(mk_contains(x3, expr->get_arg(1))));
thenItems.push_back(mk_not(m, mk_contains(x3, expr->get_arg(1))));
thenItems.push_back(ctx.mk_eq_atom(result, mk_concat(x1, mk_concat(expr->get_arg(2), x2))));
// -----------------------
// false branch
@ -1599,7 +1607,7 @@ namespace smt {
expr_ref tl(mk_str_var("tl"), m);
expr_ref conclusion1(ctx.mk_eq_atom(S, mk_concat(hd, tl)), m);
expr_ref conclusion2(ctx.mk_eq_atom(mk_strlen(hd), m_autil.mk_numeral(rational::one(), true)), m);
expr_ref conclusion3(m.mk_not(ctx.mk_eq_atom(hd, mk_string("0"))), m);
expr_ref conclusion3(mk_not(m, ctx.mk_eq_atom(hd, mk_string("0"))), m);
expr_ref conclusion(m.mk_and(conclusion1, conclusion2, conclusion3), m);
SASSERT(premise);
SASSERT(conclusion);
@ -1623,7 +1631,7 @@ namespace smt {
// axiom 1: N < 0 <==> (str.from-int N) = ""
expr * N = ex->get_arg(0);
{
expr_ref axiom1_lhs(m.mk_not(m_autil.mk_ge(N, m_autil.mk_numeral(rational::zero(), true))), m);
expr_ref axiom1_lhs(mk_not(m, m_autil.mk_ge(N, m_autil.mk_numeral(rational::zero(), true))), m);
expr_ref axiom1_rhs(ctx.mk_eq_atom(ex, mk_string("")), m);
expr_ref axiom1(ctx.mk_eq_atom(axiom1_lhs, axiom1_rhs), m);
SASSERT(axiom1);
@ -1686,6 +1694,8 @@ namespace smt {
u.str.is_string(range1, range1val);
u.str.is_string(range2, range2val);
return zstring("[") + range1val + zstring("-") + range2val + zstring("]");
} else if (u.re.is_full(a_regex)) {
return zstring("(.*)");
} else {
TRACE("str", tout << "BUG: unrecognized regex term " << mk_pp(regex, get_manager()) << std::endl;);
UNREACHABLE(); return zstring("");
@ -1716,6 +1726,12 @@ namespace smt {
expr_ref str(ex->get_arg(0), m);
app * regex = to_app(ex->get_arg(1));
// quick reference for the following code:
// - ex: top-level regex membership term
// - str: string term appearing in ex
// - regex: regex term appearing in ex
// ex ::= (str.in.re str regex)
if (u.re.is_to_re(regex)) {
expr_ref rxStr(regex->get_arg(0), m);
// want to assert 'expr IFF (str == rxStr)'
@ -1795,6 +1811,9 @@ namespace smt {
expr_ref finalAxiom(m.mk_iff(ex, rhs), m);
SASSERT(finalAxiom);
assert_axiom(finalAxiom);
} else if (u.re.is_full(regex)) {
// trivially true for any string!
assert_axiom(ex);
} else {
TRACE("str", tout << "ERROR: unknown regex expression " << mk_pp(regex, m) << "!" << std::endl;);
NOT_IMPLEMENTED_YET();
@ -1851,7 +1870,7 @@ namespace smt {
// inconsistency check: value
if (!can_two_nodes_eq(eqc_nn1, eqc_nn2)) {
TRACE("str", tout << "inconsistency detected: " << mk_pp(eqc_nn1, m) << " cannot be equal to " << mk_pp(eqc_nn2, m) << std::endl;);
expr_ref to_assert(m.mk_not(ctx.mk_eq_atom(eqc_nn1, eqc_nn2)), m);
expr_ref to_assert(mk_not(m, ctx.mk_eq_atom(eqc_nn1, eqc_nn2)), m);
assert_axiom(to_assert);
// this shouldn't use the integer theory at all, so we don't allow the option of quick-return
return false;
@ -2064,7 +2083,7 @@ namespace smt {
expr_ref implyR11(ctx.mk_eq_atom(mk_strlen(arg1), mk_int(makeUpLenArg1)), m);
assert_implication(implyL11, implyR11);
} else {
expr_ref neg(m.mk_not(implyL11), m);
expr_ref neg(mk_not(m, implyL11), m);
assert_axiom(neg);
}
}
@ -2135,7 +2154,7 @@ namespace smt {
expr_ref implyR11(ctx.mk_eq_atom(mk_strlen(arg0), mk_int(makeUpLenArg0)), m);
assert_implication(implyL11, implyR11);
} else {
expr_ref neg(m.mk_not(implyL11), m);
expr_ref neg(mk_not(m, implyL11), m);
assert_axiom(neg);
}
}
@ -2666,7 +2685,7 @@ namespace smt {
}
if (!can_two_nodes_eq(new_nn1, new_nn2)) {
expr_ref detected(m.mk_not(ctx.mk_eq_atom(new_nn1, new_nn2)), m);
expr_ref detected(mk_not(m, ctx.mk_eq_atom(new_nn1, new_nn2)), m);
TRACE("str", tout << "inconsistency detected: " << mk_ismt2_pp(detected, m) << std::endl;);
assert_axiom(detected);
return;
@ -4656,12 +4675,10 @@ namespace smt {
bool theory_str::get_arith_value(expr* e, rational& val) const {
context& ctx = get_context();
ast_manager & m = get_manager();
// safety
if (!ctx.e_internalized(e)) {
// safety
if (!ctx.e_internalized(e)) {
return false;
}
}
// if an integer constant exists in the eqc, it should be the root
enode * en_e = ctx.get_enode(e);
enode * root_e = en_e->get_root();
@ -4671,6 +4688,11 @@ namespace smt {
} else {
TRACE("str", tout << "root of eqc of " << mk_pp(e, m) << " is not a numeral" << std::endl;);
return false;
theory_mi_arith* tha = get_th_arith(ctx, m_autil.get_family_id(), e);
if (!tha) return false;
expr_ref val_e(m);
if (tha->get_value(root_e, val_e) && m_autil.is_numeral(val_e, val) && val.is_int()) return true;
return false;
}
}
@ -4907,7 +4929,7 @@ namespace smt {
implyR = boolVar;
} else {
//implyR = Z3_mk_eq(ctx, boolVar, Z3_mk_false(ctx));
implyR = m.mk_not(boolVar);
implyR = mk_not(m, boolVar);
}
} else {
// ------------------------------------------------------------------------------------------------
@ -4936,7 +4958,7 @@ namespace smt {
litems.push_back(ctx.mk_eq_atom(substrAst, aConcat));
}
//implyR = Z3_mk_eq(ctx, boolVar, Z3_mk_false(ctx));
implyR = m.mk_not(boolVar);
implyR = mk_not(m, boolVar);
break;
}
}
@ -4975,7 +4997,7 @@ namespace smt {
implyR = boolVar;
} else {
// implyR = Z3_mk_eq(ctx, boolVar, Z3_mk_false(ctx));
implyR = m.mk_not(boolVar);
implyR = mk_not(m, boolVar);
}
}
@ -5045,7 +5067,7 @@ namespace smt {
litems.push_back(ctx.mk_eq_atom(substrAst, aConcat));
}
expr_ref implyLHS(mk_and(litems), m);
expr_ref implyR(m.mk_not(boolVar), m);
expr_ref implyR(mk_not(m, boolVar), m);
assert_implication(implyLHS, implyR);
break;
}
@ -6190,24 +6212,31 @@ namespace smt {
expr * arg_str = a->get_arg(0);
zstring str;
if (u.str.is_string(arg_str, str)) {
TRACE("str", tout << "build NFA for '" << str << "'" << "\n";);
/*
* For an n-character string, we make (n-1) intermediate states,
* labelled i_(0) through i_(n-2).
* Then we construct the following transitions:
* start --str[0]--> i_(0) --str[1]--> i_(1) --...--> i_(n-2) --str[n-1]--> final
*/
unsigned last = start;
for (int i = 0; i <= ((int)str.length()) - 2; ++i) {
unsigned i_state = next_id();
make_transition(last, str[i], i_state);
TRACE("str", tout << "string transition " << last << "--" << str[i] << "--> " << i_state << "\n";);
last = i_state;
if (str.length() == 0) {
// transitioning on the empty string is handled specially
TRACE("str", tout << "empty string epsilon-move " << start << " --> " << end << std::endl;);
make_epsilon_move(start, end);
} else {
TRACE("str", tout << "build NFA for '" << str << "'" << "\n";);
/*
* For an n-character string, we make (n-1) intermediate states,
* labelled i_(0) through i_(n-2).
* Then we construct the following transitions:
* start --str[0]--> i_(0) --str[1]--> i_(1) --...--> i_(n-2) --str[n-1]--> final
*/
unsigned last = start;
for (int i = 0; i <= ((int)str.length()) - 2; ++i) {
unsigned i_state = next_id();
make_transition(last, str[i], i_state);
TRACE("str", tout << "string transition " << last << "--" << str[i] << "--> " << i_state << "\n";);
last = i_state;
}
make_transition(last, str[(str.length() - 1)], end);
TRACE("str", tout << "string transition " << last << "--" << str[(str.length() - 1)] << "--> " << end << "\n";);
}
make_transition(last, str[(str.length() - 1)], end);
TRACE("str", tout << "string transition " << last << "--" << str[(str.length() - 1)] << "--> " << end << "\n";);
} else {
TRACE("str", tout << "invalid string constant in Str2Reg" << std::endl;);
} else { // ! u.str.is_string(arg_str, str)
TRACE("str", tout << "WARNING: invalid string constant in str.to.re! Cancelling." << std::endl;);
u.get_manager().raise_exception("invalid term in str.to.re, argument must be a string constant");
m_valid = false;
return;
}
@ -6279,6 +6308,19 @@ namespace smt {
}
TRACE("str", tout << "range NFA: start = " << start << ", end = " << end << std::endl;);
} else if (u.re.is_full(e)) {
// effectively the same as .* where . can be any single character
// start --e--> tmp
// tmp --e--> end
// tmp --C--> tmp for every character C
unsigned tmp = next_id();
make_epsilon_move(start, tmp);
make_epsilon_move(tmp, end);
for (unsigned int i = 0; i < 256; ++i) {
char ch = (char)i;
make_transition(tmp, ch, tmp);
}
TRACE("str", tout << "re.all NFA: start = " << start << ", end = " << end << std::endl;);
} else {
TRACE("str", tout << "invalid regular expression" << std::endl;);
m_valid = false;
@ -6394,7 +6436,7 @@ namespace smt {
if (matchRes) {
assert_implication(implyL, boolVar);
} else {
assert_implication(implyL, m.mk_not(boolVar));
assert_implication(implyL, mk_not(m, boolVar));
}
}
}
@ -6482,7 +6524,7 @@ namespace smt {
<< arg1_str << "\" + \"" << arg2_str <<
"\" != \"" << const_str << "\"" << "\n";);
expr_ref equality(ctx.mk_eq_atom(concat, str), m);
expr_ref diseq(m.mk_not(equality), m);
expr_ref diseq(mk_not(m, equality), m);
assert_axiom(diseq);
return;
}
@ -6500,7 +6542,7 @@ namespace smt {
"\" is longer than \"" << const_str << "\","
<< " so cannot be concatenated with anything to form it" << "\n";);
expr_ref equality(ctx.mk_eq_atom(newConcat, str), m);
expr_ref diseq(m.mk_not(equality), m);
expr_ref diseq(mk_not(m, equality), m);
assert_axiom(diseq);
return;
} else {
@ -6514,7 +6556,7 @@ namespace smt {
<< "actually \"" << arg2_str << "\""
<< "\n";);
expr_ref equality(ctx.mk_eq_atom(newConcat, str), m);
expr_ref diseq(m.mk_not(equality), m);
expr_ref diseq(mk_not(m, equality), m);
assert_axiom(diseq);
return;
} else {
@ -6912,7 +6954,7 @@ namespace smt {
ast_manager & m = get_manager();
if (lenTester_fvar_map.contains(lenTester)) {
expr * fVar = lenTester_fvar_map[lenTester];
expr_ref toAssert(gen_len_val_options_for_free_var(fVar, lenTester, lenTesterValue), m);
expr_ref toAssert(gen_len_val_options_for_free_var(fVar, lenTester, lenTesterValue), m);
TRACE("str", tout << "asserting more length tests for free variable " << mk_ismt2_pp(fVar, m) << std::endl;);
if (toAssert) {
assert_axiom(toAssert);
@ -8451,7 +8493,7 @@ namespace smt {
} else {
TRACE("str", tout << "integer theory has no assignment for " << mk_pp(a, m) << std::endl;);
expr_ref is_zero(ctx.mk_eq_atom(a, m_autil.mk_int(0)), m);
literal is_zero_l = mk_literal(is_zero);
/* literal is_zero_l = */ mk_literal(is_zero);
axiomAdd = true;
TRACE("str", ctx.display(tout););
// NOT_IMPLEMENTED_YET();
@ -8767,15 +8809,30 @@ namespace smt {
if (concat_lhs_haseqc && concat_rhs_haseqc && !var_haseqc) {
TRACE("str", tout << "backpropagate into " << mk_pp(var, m) << " = " << mk_pp(concat, m) << std::endl
<< "LHS ~= " << mk_pp(concat_lhs_str, m) << " RHS ~= " << mk_pp(concat_rhs_str, m) << std::endl;);
zstring lhsString, rhsString;
u.str.is_string(concat_lhs_str, lhsString);
u.str.is_string(concat_rhs_str, rhsString);
zstring concatString = lhsString + rhsString;
expr_ref lhs1(ctx.mk_eq_atom(concat_lhs, concat_lhs_str), m);
expr_ref lhs2(ctx.mk_eq_atom(concat_rhs, concat_rhs_str), m);
expr_ref lhs(m.mk_and(lhs1, lhs2), m);
expr_ref rhs(ctx.mk_eq_atom(concat, mk_string(concatString)), m);
assert_implication(lhs, rhs);
// special handling: don't assert that string constants are equal to themselves
expr_ref_vector lhs_terms(m);
if (!u.str.is_string(concat_lhs)) {
lhs_terms.push_back(ctx.mk_eq_atom(concat_lhs, concat_lhs_str));
}
if (!u.str.is_string(concat_rhs)) {
lhs_terms.push_back(ctx.mk_eq_atom(concat_rhs, concat_rhs_str));
}
if (lhs_terms.empty()) {
// no assumptions on LHS
expr_ref rhs(ctx.mk_eq_atom(concat, mk_string(concatString)), m);
assert_axiom(rhs);
} else {
expr_ref lhs(mk_and(lhs_terms), m);
expr_ref rhs(ctx.mk_eq_atom(concat, mk_string(concatString)), m);
assert_implication(lhs, rhs);
}
backpropagation_occurred = true;
}
}