adding simplifiers layer

simplifiers layer is a common substrate for global non-incremental and incremental processing.
The first two layers are new, but others are to be ported form tactics.

- bv::slice - rewrites equations to cut-dice-slice bit-vector extractions until they align. It creates opportunities for rewriting portions of bit-vectors to common sub-expressions, including values.
- euf::completion - generalizes the KB simplifcation from asserted formulas to use the E-graph to establish a global and order-independent canonization.

The interface dependent_expr_simplifier is amenable to forming tactics. Plugins for asserted-formulas is also possible but not yet realized.

src/tactic/core/CMakeLists.txt

@@ -10,6 +10,7 @@ z3_add_component(core_tactics
     dom_simplify_tactic.cpp
     elim_term_ite_tactic.cpp
     elim_uncnstr_tactic.cpp
+    euf_completion_tactic.cpp
     injectivity_tactic.cpp
     nnf_tactic.cpp
     occf_tactic.cpp
@@ -38,6 +39,7 @@ z3_add_component(core_tactics
     dom_simplify_tactic.h
     elim_term_ite_tactic.h
     elim_uncnstr_tactic.h
+    euf_completion_tactic.h
     injectivity_tactic.h
     nnf_tactic.h
     occf_tactic.h

src/tactic/core/euf_completion_tactic.cpp

@@ -0,0 +1,32 @@
+/*++
+Copyright (c) 2022 Microsoft Corporation
+
+Module Name:
+
+    euf_completion_tactic.cpp
+
+Abstract:
+
+    Tactic for simplifying with equations.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2022-10-30
+
+--*/
+
+#include "tactic/tactic.h"
+#include "tactic/dependent_expr_state_tactic.h"
+#include "ast/simplifiers/euf_completion.h"
+#include "tactic/core/euf_completion_tactic.h"
+
+class euf_completion_tactic_factory : public dependent_expr_simplifier_factory {
+public:
+    dependent_expr_simplifier* mk(ast_manager& m, params_ref const& p, dependent_expr_state& s) override {
+        return alloc(euf::completion, m, s);
+    }
+};
+
+tactic * mk_euf_completion_tactic(ast_manager& m, params_ref const& p) {
+    return alloc(dependent_expr_state_tactic, m, p, alloc(euf_completion_tactic_factory), "euf-completion");
+}

src/tactic/core/euf_completion_tactic.h

@@ -0,0 +1,29 @@
+/*++
+Copyright (c) 2022 Microsoft Corporation
+
+Module Name:
+
+    euf_completion_tactic.h
+
+Abstract:
+
+    Tactic for simplifying with equations.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2022-10-30
+
+--*/
+#pragma once
+
+#include "util/params.h"
+class ast_manager;
+class tactic;
+
+tactic * mk_euf_completion_tactic(ast_manager & m, params_ref const & p = params_ref());
+
+/*
+  ADD_TACTIC("euf-completion", "simplify using equalities.", "mk_euf_completion_tactic(m, p)")
+*/
+
+