Bugfix in wreduce

diff --git a/passes/opt/wreduce.cc b/passes/opt/wreduce.cc
index 1609a8be79a041bf65c803fca819772146536a60..9a84dafe1ea7388052984127dbfae6bd2f66ed64 100644 (file)
--- a/passes/opt/wreduce.cc
+++ b/passes/opt/wreduce.cc
@@ -281,6 +281,10 @@ struct WreduceWorker
                                        work_queue_cells.insert(port.cell);
                }
 
+               pool<SigSpec> complete_wires;
+               for (auto w : module->wires())
+                       complete_wires.insert(mi.sigmap(w));
+
                for (auto w : module->selected_wires())
                {
                        int unused_top_bits = 0;
@@ -296,13 +300,16 @@ struct WreduceWorker
                                unused_top_bits++;
                        }
 
-                       if (0 < unused_top_bits && unused_top_bits < GetSize(w)) {
-                               log("Removed top %d bits (of %d) from wire %s.%s.\n", unused_top_bits, GetSize(w), log_id(module), log_id(w));
-                               Wire *nw = module->addWire(NEW_ID, w);
-                               nw->width = GetSize(w) - unused_top_bits;
-                               module->connect(nw, SigSpec(w).extract(0, GetSize(nw)));
-                               module->swap_names(w, nw);
-                       }
+                       if (unused_top_bits == 0 || unused_top_bits == GetSize(w))
+                               continue;
+
+                       if (complete_wires[mi.sigmap(w).extract(0, GetSize(w) - unused_top_bits)])
+                               continue;
+
+                       log("Removed top %d bits (of %d) from wire %s.%s.\n", unused_top_bits, GetSize(w), log_id(module), log_id(w));
+                       Wire *nw = module->addWire(NEW_ID, GetSize(w) - unused_top_bits);
+                       module->connect(nw, SigSpec(w).extract(0, GetSize(nw)));
+                       module->swap_names(w, nw);
                }
        }
 };