interchange: add support for generating BEL clusters

Clustering greatly helps the placer to identify and pack together
specific cells at the same site (e.g. LUT+FF), or cells that are chained through
dedicated interconnections (e.g. CARRY CHAINS)

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fpga_interchange/arch.cc b/fpga_interchange/arch.cc
index 8e7fe2a3..1bbe9a02 100644
--- a/fpga_interchange/arch.cc
+++ b/fpga_interchange/arch.cc
@@ -758,6 +758,7 @@ bool Arch::pack()
     pack_ports();
     pack_default_conns();
     expand_macros();
+    pack_cluster();
     return true;
 }