From 8242069ba6a9e6615317723f1495ee23b1c24055 Mon Sep 17 00:00:00 2001
From: Jakob Rath <git@jakobrath.eu>
Date: Thu, 29 Sep 2022 18:22:31 +0200
Subject: [PATCH] One more case for ule_constraint::is_always_false

---
 src/math/dd/dd_pdd.h                | 2 ++
 src/math/polysat/ule_constraint.cpp | 4 +++-
 src/math/polysat/ule_constraint.h   | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/math/dd/dd_pdd.h b/src/math/dd/dd_pdd.h
index d003461e7..6c7497461 100644
--- a/src/math/dd/dd_pdd.h
+++ b/src/math/dd/dd_pdd.h
@@ -253,6 +253,7 @@ namespace dd {
         inline bool is_val(PDD p) const { return m_nodes[p].is_val(); }
         inline bool is_internal(PDD p) const { return m_nodes[p].is_internal(); }
         inline bool is_var(PDD p) const { return !is_val(p) && is_zero(lo(p)) && is_one(hi(p)); }
+        inline bool is_max(PDD p) const { SASSERT(m_semantics == mod2_e || m_semantics == mod2N_e); return is_val(p) && val(p) == max_value(); }
         bool is_never_zero(PDD p);
         inline unsigned level(PDD p) const { return m_nodes[p].m_level; }
         inline unsigned var(PDD p) const { return m_level2var[level(p)]; }
@@ -413,6 +414,7 @@ namespace dd {
         bool is_zero() const { return m.is_zero(root); }
         bool is_linear() const { return m.is_linear(root); }
         bool is_var() const { return m.is_var(root); }
+        bool is_max() const { return m.is_max(root); }
         /** Polynomial is of the form a * x + b for numerals a, b. */
         bool is_unilinear() const { return !is_val() && lo().is_val() && hi().is_val(); }
         bool is_unary() const { return !is_val() && lo().is_zero() && hi().is_val(); }
diff --git a/src/math/polysat/ule_constraint.cpp b/src/math/polysat/ule_constraint.cpp
index 9e3ca4200..2a0326ff0 100644
--- a/src/math/polysat/ule_constraint.cpp
+++ b/src/math/polysat/ule_constraint.cpp
@@ -70,7 +70,7 @@ namespace {
             return;
         }
         // p <= -1   -->   0 <= 0
-        if (rhs.is_val() && rhs.val() == rhs.manager().max_value()) {
+        if (rhs.is_max()) {
             lhs = 0, rhs = 0;
             return;
         }
@@ -202,6 +202,8 @@ namespace polysat {
                 return true;  // 0 > ... is always false
             if (lhs == rhs)
                 return true;  // p > p
+            if (rhs.is_max())
+                return true;  // p > -1
             if (lhs.is_one() && rhs.is_never_zero())
                 return true;  // 1 > p implies p == 0
             return lhs.is_val() && rhs.is_val() && lhs.val() <= rhs.val();
diff --git a/src/math/polysat/ule_constraint.h b/src/math/polysat/ule_constraint.h
index 01eb57b93..ddbb3cc96 100644
--- a/src/math/polysat/ule_constraint.h
+++ b/src/math/polysat/ule_constraint.h
@@ -27,6 +27,7 @@ namespace polysat {
 
         ule_constraint(constraint_manager& m, pdd const& l, pdd const& r);
         static void simplify(bool& is_positive, pdd& lhs, pdd& rhs);
+        static bool is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs);
 
     public:
         ~ule_constraint() override {}
@@ -35,7 +36,6 @@ namespace polysat {
         static std::ostream& display(std::ostream& out, lbool status, pdd const& lhs, pdd const& rhs);
         std::ostream& display(std::ostream& out, lbool status) const override;
         std::ostream& display(std::ostream& out) const override;
-        static bool is_always_false(bool is_positive, pdd const& lhs, pdd const& rhs);
         bool is_always_false(bool is_positive) const override;
         bool is_currently_false(solver& s, bool is_positive) const override;
         bool is_currently_false(solver& s, assignment_t const& sub, bool is_positive) const override;