opt_clean: Fix module keep rules.

- wires with keep attribute now force a module to be kept
- presence of $memwr and $meminit cells no longer forces a module to be
  kept

diff --git a/passes/opt/opt_clean.cc b/passes/opt/opt_clean.cc
index 44de60b48c402585d77bcaa91ddf307f4bc212dd..5370881d3f1c723a8efcdaebad36f89f0542fc49 100644 (file)
--- a/passes/opt/opt_clean.cc
+++ b/passes/opt/opt_clean.cc
@@ -55,7 +55,12 @@ struct keep_cache_t
                if (!module->get_bool_attribute(ID::keep)) {
                    bool found_keep = false;
                    for (auto cell : module->cells())
-                       if (query(cell, true /* ignore_specify */)) {
+                       if (query(cell, true /* ignore_specify_mem */)) {
+                           found_keep = true;
+                           break;
+                       }
+                   for (auto wire : module->wires())
+                       if (wire->get_bool_attribute(ID::keep)) {
                            found_keep = true;
                            break;
                        }
@@ -65,12 +70,12 @@ struct keep_cache_t
                return cache[module];
        }
 
-       bool query(Cell *cell, bool ignore_specify = false)
+       bool query(Cell *cell, bool ignore_specify_mem = false)
        {
-               if (cell->type.in(ID($memwr), ID($meminit), ID($assert), ID($assume), ID($live), ID($fair), ID($cover)))
+               if (cell->type.in(ID($assert), ID($assume), ID($live), ID($fair), ID($cover)))
                        return true;
 
-               if (!ignore_specify && cell->type.in(ID($specify2), ID($specify3), ID($specrule)))
+               if (!ignore_specify_mem && cell->type.in(ID($memwr), ID($meminit), ID($specify2), ID($specify3), ID($specrule)))
                        return true;
 
                if (cell->has_keep_attr())