Valid to have attribute starting with SB_CARRY.

diff --git a/techlibs/ice40/ice40_opt.cc b/techlibs/ice40/ice40_opt.cc
index 371ceb623486d6c69a9fb1ac343ce3054827dd3a..9bee0444b13853cf122dbd268e33bfdc4a0bbbc7 100644 (file)
--- a/techlibs/ice40/ice40_opt.cc
+++ b/techlibs/ice40/ice40_opt.cc
@@ -128,6 +128,8 @@ static void run_ice40_opts(Module *module)
                                                        new_attr.insert(std::make_pair(a.first, a.second));
                                                else if (a.first.in(ID(SB_LUT4.name), ID::keep, ID(module_not_derived)))
                                                        continue;
+                                               else if (a.first.begins_with("\\SB_CARRY.\\"))
+                                                       continue;
                                                else
                                                        log_abort();
                                        cell->attributes = std::move(new_attr);