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[bv_bounds] introduce a tight bit in intervals to denote they are tight (over and under approx)

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use this to ensure certain transformations remain sound
This commit is contained in:
Nuno Lopes 2016-02-18 15:53:11 +00:00
parent 67958efed2
commit d32b4c71d1
3 changed files with 69 additions and 32 deletions
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27
src/tactic/core/ctx_simplify_tactic.cpp
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@ -34,7 +34,7 @@ class ctx_propagate_assertions : public ctx_simplify_tactic::simplifier {
public:
ctx_propagate_assertions(ast_manager& m);
virtual ~ctx_propagate_assertions() {}
virtual void assert_expr(expr * t, bool sign);
virtual bool assert_expr(expr * t, bool sign);
virtual bool simplify(expr* t, expr_ref& result);
virtual void push();
virtual void pop(unsigned num_scopes);
@ -45,7 +45,7 @@ public:
ctx_propagate_assertions::ctx_propagate_assertions(ast_manager& m): m(m), m_trail(m) {}
void ctx_propagate_assertions::assert_expr(expr * t, bool sign) {
bool ctx_propagate_assertions::assert_expr(expr * t, bool sign) {
expr * p = t;
while (m.is_not(t, t)) {
@ -64,6 +64,7 @@ void ctx_propagate_assertions::assert_expr(expr * t, bool sign) {
else if (m.is_value(lhs))
assert_eq_val(rhs, to_app(lhs), mk_scope);
}
return true;
}
void ctx_propagate_assertions::assert_eq_val(expr * t, app * val, bool mk_scope) {
@ -307,8 +308,8 @@ struct ctx_simplify_tactic::imp {
CASSERT("ctx_simplify_tactic", check_cache());
}
void assert_expr(expr * t, bool sign) {
m_simp->assert_expr(t, sign);
bool assert_expr(expr * t, bool sign) {
return m_simp->assert_expr(t, sign);
}
bool is_cached(expr * t, expr_ref & r) {
@ -370,6 +371,9 @@ struct ctx_simplify_tactic::imp {
simplify(arg, new_arg);
if (new_arg != arg)
modified = true;
if (i < num_args - 1 && !m.is_true(new_arg) && !m.is_false(new_arg) && !assert_expr(new_arg, OR))
new_arg = m.mk_false();
if ((OR && m.is_false(new_arg)) ||
(!OR && m.is_true(new_arg))) {
modified = true;
@ -383,8 +387,6 @@ struct ctx_simplify_tactic::imp {
return;
}
new_args.push_back(new_arg);
if (i < num_args - 1)
assert_expr(new_arg, OR);
}
pop(scope_level() - old_lvl);
@ -398,6 +400,9 @@ struct ctx_simplify_tactic::imp {
simplify(arg, new_arg);
if (new_arg != arg)
modified = true;
if (i > 0 && !m.is_true(new_arg) && !m.is_false(new_arg) && !assert_expr(new_arg, OR))
new_arg = m.mk_false();
if ((OR && m.is_false(new_arg)) ||
(!OR && m.is_true(new_arg))) {
modified = true;
@ -411,8 +416,6 @@ struct ctx_simplify_tactic::imp {
return;
}
new_new_args.push_back(new_arg);
if (i > 0)
assert_expr(new_arg, OR);
}
pop(scope_level() - old_lvl);
@ -448,10 +451,14 @@ struct ctx_simplify_tactic::imp {
else {
expr_ref new_t(m);
expr_ref new_e(m);
assert_expr(new_c, false);
if (!assert_expr(new_c, false)) {
simplify(e, r);
cache(ite, r);
return;
}
simplify(t, new_t);
pop(scope_level() - old_lvl);
assert_expr(new_c, true);
VERIFY(assert_expr(new_c, true));
simplify(e, new_e);
pop(scope_level() - old_lvl);
if (c == new_c && t == new_t && e == new_e) {

2
src/tactic/core/ctx_simplify_tactic.h
View file

@ -28,7 +28,7 @@ public:
goal_num_occurs* m_occs;
public:
virtual ~simplifier() {}
virtual void assert_expr(expr * t, bool sign) = 0;
virtual bool assert_expr(expr * t, bool sign) = 0;
virtual bool simplify(expr* t, expr_ref& result) = 0;
virtual void push() = 0;
virtual void pop(unsigned num_scopes) = 0;