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wip - updated version of elim_uncstr_tactic

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- remove reduce_invertible. It is subsumed by reduce_uncstr(2)
- introduce a simplifier for reduce_unconstrained. It uses reference counting to deal with inefficiency bug of legacy reduce_uncstr. It decomposes theory plugins into expr_inverter.

reduce_invertible is a tactic used in most built-in scenarios. It is useful for removing subterms that can be eliminated using "cheap" quantifier elimination. Specifically variables that occur only once can be removed in many cases by computing an expression that represents the effect computing a value for the eliminated occurrence.

The theory plugins for variable elimination are very partial and should be augmented by extensions, esp. for the case of bit-vectors where the invertibility conditions are thoroughly documented by Niemetz and Preiner.
This commit is contained in:
Nikolaj Bjorner 2022-11-12 17:56:45 -08:00
parent 689af3b4df
commit efbe0a6554
20 changed files with 1334 additions and 621 deletions
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13
src/ast/simplifiers/model_reconstruction_trail.h
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@ -35,11 +35,14 @@ class model_reconstruction_trail {
struct entry {
scoped_ptr<expr_substitution> m_subst;
vector<dependent_expr> m_removed;
func_decl* m_hide = nullptr;
bool m_active = true;
entry(expr_substitution* s, vector<dependent_expr> const& rem) :
m_subst(s), m_removed(rem) {}
entry(func_decl* h) : m_hide(h) {}
bool is_loose() const { return !m_removed.empty(); }
bool intersects(ast_mark const& free_vars) const {
@ -48,8 +51,6 @@ class model_reconstruction_trail {
return true;
return false;
}
};
ast_manager& m;
@ -81,6 +82,14 @@ public:
*/
void push(expr_substitution* s, vector<dependent_expr> const& removed) {
m_trail.push_back(alloc(entry, s, removed));
m_trail_stack.push(push_back_vector(m_trail));
}
/**
* add declaration to hide
*/
void push(func_decl* f) {
m_trail.push_back(alloc(entry, f));
m_trail_stack.push(push_back_vector(m_trail));
}