DRC: deep mode region input does not flatten the layout on clip

src/db/db/dbHierarchyBuilder.cc

@@ -534,9 +534,12 @@ ClippingHierarchyBuilderShapeReceiver::insert_clipped (const db::Box &box, const
 
   if (complex_region) {
     for (db::RecursiveShapeReceiver::box_tree_type::overlapping_iterator cr = complex_region->begin_overlapping (bb, db::box_convert<db::Box> ()); ! cr.at_end (); ++cr) {
-      mp_pipe->push (*cr & bb, trans, world, 0, target);
+      db::Box bc = *cr & bb;
+      if (! bc.empty ()) {
+        mp_pipe->push (bc, trans, world, 0, target);
       }
-  } else {
+    }
+  } else if (! bb.empty ()) {
     mp_pipe->push (bb, trans, world, 0, target);
   }
 }

src/drc/drc/built-in-macros/_drc_engine.rb

@@ -2536,9 +2536,13 @@ CODE
         end
         
         # clip if a box is specified
-        if box && clip && (cls == RBA::Region || cls == RBA::Edge)
+        # TODO: the whole clip thing could be a part of the Region constructor
+        if cls == RBA::Region && clip && box
+          # HACK: deep regions will always clip in the constructor, so skip this
+          if ! @deep 
             r &= RBA::Region::new(box)
           end
+        end
       
       end