early check to see if a block can be placed in a layer

Author: soheilshahrouz

vpr/src/base/region.cpp

@@ -45,7 +45,7 @@ void Region::set_sub_tile(int sub_tile) {
     sub_tile_ = sub_tile;
 }
 
-bool Region::empty() {
+bool Region::empty() const {
     const vtr::Rect<int>& rect = region_bounds_.get_rect();
     const auto [layer_begin, layer_end] = region_bounds_.get_layer_range();
 

vpr/src/base/region.h

@@ -100,7 +100,7 @@ class Region {
      * @brief Return whether the region is empty (i. e. the region bounds rectangle
      * covers no area)
      */
-    bool empty();
+    bool empty() const;
 
     /**
      * @brief Check if the location is in the region (at a valid x, y, subtile location within the region bounds, inclusive)

vpr/src/place/move_utils.cpp

@@ -1274,6 +1274,10 @@ bool intersect_range_limit_with_floorplan_constraints(ClusterBlockId b_from,
      * complicated case to get correct functionality during place moves.
      */
     if (compressed_regions.size() == 1) {
+        if (compressed_regions[0].empty()) {
+            return false;
+        }
+
         Region range_reg;
         range_reg.set_region_bounds({search_range.xmin, search_range.ymin,
                                      search_range.xmax, search_range.ymax,