Fixed performance bug in "share" pass

diff --git a/passes/opt/share.cc b/passes/opt/share.cc
index 1d9b1006ed4e31de5d98a8497e46010a890ef369..7927c539747887318f1ceb661fa010b84bcb0587 100644 (file)
--- a/passes/opt/share.cc
+++ b/passes/opt/share.cc
@@ -793,10 +793,59 @@ struct ShareWorker
                return true;
        }
 
-       void optimize_activation_patterns(pool<ssc_pair_t> & /* patterns */)
+       void optimize_activation_patterns(pool<ssc_pair_t> &patterns)
        {
                // TODO: Remove patterns that are contained in other patterns
-               // TODO: Consolidate pairs of patterns that only differ in the value for one signal bit
+
+               dict<SigSpec, pool<Const>> db;
+               bool did_something = false;
+
+               for (auto const &p : patterns)
+               {
+                       auto &sig = p.first;
+                       auto &val = p.second;
+                       int len = GetSize(sig);
+
+                       for (int i = 0; i < len; i++)
+                       {
+                               auto otherval = val;
+
+                               if (otherval.bits[i] == State::S0)
+                                       otherval.bits[i] = State::S1;
+                               else if (otherval.bits[i] == State::S1)
+                                       otherval.bits[i] = State::S0;
+                               else
+                                       continue;
+
+                               if (db[sig].count(otherval))
+                               {
+                                       auto newsig = sig;
+                                       newsig.remove(i);
+
+                                       auto newval = val;
+                                       newval.bits.erase(newval.bits.begin() + i);
+
+                                       db[newsig].insert(newval);
+                                       db[sig].erase(otherval);
+
+                                       did_something = true;
+                                       goto next_pattern;
+                               }
+                       }
+
+                       db[sig].insert(val);
+               next_pattern:;
+               }
+
+               if (!did_something)
+                       return;
+
+               patterns.clear();
+               for (auto &it : db)
+               for (auto &val : it.second)
+                       patterns.insert(make_pair(it.first, val));
+
+               optimize_activation_patterns(patterns);
        }
 
        const pool<ssc_pair_t> &find_cell_activation_patterns(RTLIL::Cell *cell, const char *indent)