equivalent tiles: corrected bug that produced bad tile swap

Signed-off-by: Alessandro Comodi <[email protected]>

Author: acomodi

vpr/src/place/place.cpp

@@ -1839,7 +1839,7 @@ static e_swap_result try_swap(float t,
 
 	// Find random equivalent type (could be of the same type as the `from` one)
 	if (to_block_type->num_equivalent_tiles > 0) {
-		int irand_block_type = std::rand() % (to_block_type->num_equivalent_tiles + 1);
+		int irand_block_type = vtr::irand(to_block_type->num_equivalent_tiles);
 
 		// If random index is 0 do not use an equivalent tile.
 		if (irand_block_type > 0) {
@@ -2265,7 +2265,11 @@ static bool find_to(t_type_ptr to_type, t_type_ptr from_type, float rlim, const
     VTR_ASSERT_MSG(device_ctx.grid[to.x][to.y].width_offset == 0, "Should be at block base location");
     VTR_ASSERT_MSG(device_ctx.grid[to.x][to.y].height_offset == 0, "Should be at block base location");
 
-    return true;
+    auto& place_ctx = g_vpr_ctx.placement();
+
+    ClusterBlockId b_from = place_ctx.grid_blocks[from.x][from.y].blocks[from.z];
+
+    return is_legal_swap_to_location(b_from, to);
 }
 
 static e_swap_result assess_swap(float delta_c, float t) {