diff --git a/fpga_interchange/arch.cc b/fpga_interchange/arch.cc
index c49a172bd42..a478f7e543e 100644
--- a/fpga_interchange/arch.cc
+++ b/fpga_interchange/arch.cc
@@ -1811,6 +1811,8 @@ bool Arch::checkPipAvailForNet(PipId pip, NetInfo *net) const
                     auto &bel_data = bel_info(chip_info, user.cell->bel);
                     if (bel_data.site == pip_data.site) {
                         valid_pip = true;
+                    } else {
+                        valid_pip = false;
                         break;
                     }
                 }