From 15dc7b78a0747619b3e4ab0c800a08ec001fcc38 Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Thu, 24 Nov 2022 15:09:13 +0700
Subject: [PATCH] Move merge_tf handling to euf_internalize
literals true/false are not necessarily created when the merge flag is set.
Also disable merge_tf for if-then-else expressions
Perhaps even not insert children of if expressions into congruence table?
---
src/ast/euf/euf_egraph.cpp | 12 ++----------
src/sat/smt/euf_internalize.cpp | 27 +++++++++++++++++++++++++++
src/sat/smt/euf_solver.h | 2 --
3 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/src/ast/euf/euf_egraph.cpp b/src/ast/euf/euf_egraph.cpp
index 037020a2e..ad88f839f 100644
--- a/src/ast/euf/euf_egraph.cpp
+++ b/src/ast/euf/euf_egraph.cpp
@@ -36,10 +36,8 @@ namespace euf {
}
m_expr2enode.setx(f->get_id(), n, nullptr);
push_node(n);
- for (unsigned i = 0; i < num_args; ++i) {
- set_cgc_enabled(args[i], true);
- set_merge_tf_enabled(args[i], true);
- }
+ for (unsigned i = 0; i < num_args; ++i)
+ set_cgc_enabled(args[i], true);
return n;
}
@@ -271,12 +269,6 @@ namespace euf {
if (enable_merge_tf != n->merge_tf()) {
n->set_merge_tf(enable_merge_tf);
m_updates.push_back(update_record(n, update_record::toggle_merge_tf()));
- if (enable_merge_tf && n->value() != l_undef && !m.is_value(n->get_root()->get_expr())) {
- expr* b = n->value() == l_true ? m.mk_true() : m.mk_false();
- enode* tf = find(b);
- if (tf)
- add_literal(n, tf);
- }
}
}
diff --git a/src/sat/smt/euf_internalize.cpp b/src/sat/smt/euf_internalize.cpp
index 3aaafa36c..792ffcf1d 100644
--- a/src/sat/smt/euf_internalize.cpp
+++ b/src/sat/smt/euf_internalize.cpp
@@ -474,6 +474,33 @@ namespace euf {
enode* n = m_egraph.mk(e, m_generation, num, args);
if (si.is_bool_op(e))
m_egraph.set_cgc_enabled(n, false);
+
+ //
+ // (if p th el) (non-Boolean case) produces clauses
+ // (=> p (= (if p th el) th))
+ // and (=> (not p) (= (if p th el) el))
+ // The clauses establish equalities between the ite term and
+ // the th or el sub-terms.
+ //
+ if (m.is_ite(e))
+ num = 0;
+
+ //
+ // To track congruences of Boolean children under non-Boolean
+ // functions set the merge_tf flag to true.
+ //
+ for (unsigned i = 0; i < num; ++i) {
+ if (!m.is_bool(args[i]->get_sort()))
+ continue;
+ bool was_enabled = args[i]->merge_tf();
+ m_egraph.set_merge_tf_enabled(args[i], true);
+ if (!was_enabled && n->value() != l_undef && !m.is_value(n->get_root()->get_expr())) {
+ if (n->value() == l_true)
+ m_egraph.merge(n, mk_true(), to_ptr(sat::literal(n->bool_var())));
+ else
+ m_egraph.merge(n, mk_false(), to_ptr(~sat::literal(n->bool_var())));
+ }
+ }
return n;
}
diff --git a/src/sat/smt/euf_solver.h b/src/sat/smt/euf_solver.h
index 5b09e6a46..675ec1500 100644
--- a/src/sat/smt/euf_solver.h
+++ b/src/sat/smt/euf_solver.h
@@ -146,7 +146,6 @@ namespace euf {
constraint* m_conflict = nullptr;
constraint* m_eq = nullptr;
- constraint* m_lit = nullptr;
// proofs
bool m_proof_initialized = false;
@@ -266,7 +265,6 @@ namespace euf {
~solver() override {
if (m_conflict) dealloc(sat::constraint_base::mem2base_ptr(m_conflict));
if (m_eq) dealloc(sat::constraint_base::mem2base_ptr(m_eq));
- if (m_lit) dealloc(sat::constraint_base::mem2base_ptr(m_lit));
m_trail.reset();
}