Use ai_simplify in unwind_bounds to support FP operations

Author: chrisr-diffblue

regression/unwind-bounds/unwind_fp/main.c

@@ -0,0 +1,10 @@
+#define N (int)( (10./2.) + 0.5)
+
+void some(void);
+
+void main(void)
+{
+  int i;
+  for (i=0; i<N; i++)
+    some();
+}

regression/unwind-bounds/unwind_fp/test.desc

@@ -0,0 +1,8 @@
+CORE
+main.c
+--unwind-bounds
+^main.0: 5$
+^EXIT=0$
+^SIGNAL=0$
+--
+^warning: ignoring

src/analyses/unwind_bounds.cpp

@@ -520,8 +520,7 @@ void unwind_boundst::handle_self_loop(
 
   exprt cond=loop->guard;
 
-  entry_state.values.replace_const.replace(cond);
-  cond=simplify_expr(cond, ns);
+  entry_state.ai_simplify(cond, ns);
 
   bool c=cond.is_false();
 
@@ -605,8 +604,7 @@ void unwind_boundst::handle_loop(
   while(true)
   {
     exprt cond=loop_cond(loop);
-    next_entry_state.values.replace_const.replace(cond);
-    cond=simplify_expr(cond, ns);
+    next_entry_state.ai_simplify(cond, ns);
 
     bool c=cond.is_false();