minor fixes

- ensure mk_extract performs simplification to distribute over extract and removing extract if the range is the entire bit-vector
- ensure bool_rewriter simplifeis disjunctions when applicable.

src/ast/rewriter/bool_rewriter.cpp

@@ -290,7 +290,7 @@ br_status bool_rewriter::mk_flat_or_core(unsigned num_args, expr * const * args,
                 ast_lt lt;
                 std::sort(flat_args.begin(), flat_args.end(), lt);
             }
-            result = m().mk_or(flat_args);
+            result = mk_or_app(flat_args.size(), flat_args.data());
         }
         return BR_DONE;
     }

src/ast/rewriter/mk_extract_proc.cpp

@@ -32,8 +32,15 @@ mk_extract_proc::~mk_extract_proc() {
 }
 
 app * mk_extract_proc::operator()(unsigned high, unsigned low, expr * arg) {
+    unsigned l, h;
+    while (m_util.is_extract(arg, l, h, arg)) {
+        low += l;
+        high += l;
+    }
     ast_manager & m = m_util.get_manager();
     sort * s = arg->get_sort();
+    if (low == 0 && high + 1 == m_util.get_bv_size(arg) && is_app(arg))
+        return to_app(arg);
     if (m_low == low && m_high == high && m_domain == s)
         return m.mk_app(m_f_cached, arg);
     // m_f_cached has a reference to m_domain, so, I don't need to inc_ref m_domain

src/ast/rewriter/th_rewriter.h

@@ -47,6 +47,7 @@ public:
     expr_ref operator()(expr * n, unsigned num_bindings, expr * const * bindings);
 
     expr_ref mk_app(func_decl* f, unsigned num_args, expr* const* args);
+    expr_ref mk_app(func_decl* f, ptr_vector<expr> const& args) { return mk_app(f, args.size(), args.data()); }
 
     bool reduce_quantifier(quantifier * old_q, 
                            expr * new_body,