Invert is_assign check

To reduce indentation and make it clear that this check filters which
instructions the loop operates on.

Author: thomasspriggs

src/goto-programs/mm_io.cpp

@@ -45,64 +45,64 @@ void mm_io(
       it!=goto_function.body.instructions.end();
       it++)
   {
+    if(!it->is_assign())
+      continue;
+
     std::set<dereference_exprt> deref_expr_w, deref_expr_r;
 
-    if(it->is_assign())
-    {
-      auto &a_lhs = it->assign_lhs();
-      auto &a_rhs = it->assign_rhs_nonconst();
-      collect_deref_expr(a_rhs, deref_expr_r);
+    auto &a_lhs = it->assign_lhs();
+    auto &a_rhs = it->assign_rhs_nonconst();
+    collect_deref_expr(a_rhs, deref_expr_r);
 
-      if(mm_io_r.is_not_nil())
+    if(mm_io_r.is_not_nil())
+    {
+      if(deref_expr_r.size() == 1)
       {
-        if(deref_expr_r.size()==1)
-        {
-          const dereference_exprt &d=*deref_expr_r.begin();
-          source_locationt source_location = it->source_location();
-          const code_typet &ct=to_code_type(mm_io_r.type());
-
-          if_exprt if_expr(
-            integer_address(d.pointer()),
-            typecast_exprt::conditional_cast(mm_io_r_value, d.type()),
-            d);
-          replace_expr(d, if_expr, a_rhs);
-
-          const typet &pt=ct.parameters()[0].type();
-          const typet &st=ct.parameters()[1].type();
-          auto size_opt = size_of_expr(d.type(), ns);
-          CHECK_RETURN(size_opt.has_value());
-          auto call = goto_programt::make_function_call(
-            mm_io_r_value,
-            mm_io_r,
-            {typecast_exprt(d.pointer(), pt),
-             typecast_exprt(size_opt.value(), st)},
-            source_location);
-          goto_function.body.insert_before_swap(it, call);
-          it++;
-        }
+        const dereference_exprt &d = *deref_expr_r.begin();
+        source_locationt source_location = it->source_location();
+        const code_typet &ct = to_code_type(mm_io_r.type());
+
+        if_exprt if_expr(
+          integer_address(d.pointer()),
+          typecast_exprt::conditional_cast(mm_io_r_value, d.type()),
+          d);
+        replace_expr(d, if_expr, a_rhs);
+
+        const typet &pt = ct.parameters()[0].type();
+        const typet &st = ct.parameters()[1].type();
+        auto size_opt = size_of_expr(d.type(), ns);
+        CHECK_RETURN(size_opt.has_value());
+        auto call = goto_programt::make_function_call(
+          mm_io_r_value,
+          mm_io_r,
+          {typecast_exprt(d.pointer(), pt),
+           typecast_exprt(size_opt.value(), st)},
+          source_location);
+        goto_function.body.insert_before_swap(it, call);
+        it++;
       }
+    }
 
-      if(mm_io_w.is_not_nil())
+    if(mm_io_w.is_not_nil())
+    {
+      if(a_lhs.id() == ID_dereference)
       {
-        if(a_lhs.id() == ID_dereference)
-        {
-          const dereference_exprt &d = to_dereference_expr(a_lhs);
-          source_locationt source_location = it->source_location();
-          const code_typet &ct=to_code_type(mm_io_w.type());
-          const typet &pt=ct.parameters()[0].type();
-          const typet &st=ct.parameters()[1].type();
-          const typet &vt=ct.parameters()[2].type();
-          auto size_opt = size_of_expr(d.type(), ns);
-          CHECK_RETURN(size_opt.has_value());
-          const code_function_callt fc(
-            mm_io_w,
-            {typecast_exprt(d.pointer(), pt),
-             typecast_exprt(size_opt.value(), st),
-             typecast_exprt(a_rhs, vt)});
-          goto_function.body.insert_before_swap(it);
-          *it = goto_programt::make_function_call(fc, source_location);
-          it++;
-        }
+        const dereference_exprt &d = to_dereference_expr(a_lhs);
+        source_locationt source_location = it->source_location();
+        const code_typet &ct = to_code_type(mm_io_w.type());
+        const typet &pt = ct.parameters()[0].type();
+        const typet &st = ct.parameters()[1].type();
+        const typet &vt = ct.parameters()[2].type();
+        auto size_opt = size_of_expr(d.type(), ns);
+        CHECK_RETURN(size_opt.has_value());
+        const code_function_callt fc(
+          mm_io_w,
+          {typecast_exprt(d.pointer(), pt),
+           typecast_exprt(size_opt.value(), st),
+           typecast_exprt(a_rhs, vt)});
+        goto_function.body.insert_before_swap(it);
+        *it = goto_programt::make_function_call(fc, source_location);
+        it++;
       }
     }
   }