freduce performance fix

diff --git a/passes/sat/freduce.cc b/passes/sat/freduce.cc
index 00968c730965ffec9255e0a760c24f1ca2f70b89..d57fdd321c0a83410702c4515d691f2e31bccf1a 100644 (file)
--- a/passes/sat/freduce.cc
+++ b/passes/sat/freduce.cc
@@ -178,7 +178,7 @@ struct FreduceHelper
                return true;
        }
 
-       bool toproot_helper(RTLIL::SigSpec cursor, RTLIL::SigSpec stoplist, int level)
+       bool toproot_helper(RTLIL::SigSpec cursor, RTLIL::SigSpec stoplist, RTLIL::SigSpec &donelist, int level)
        {
                // log("    %*schecking %s: %s\n", level*2, "", log_signal(cursor), log_signal(stoplist));
 
@@ -187,13 +187,17 @@ struct FreduceHelper
                        return false;
                }
 
+               if (donelist.extract(cursor).width != 0)
+                       return true;
+
                stoplist.append(cursor);
                std::set<RTLIL::SigSpec> next = source_signals.find(cursor);
 
                for (auto &it : next)
-                       if (!toproot_helper(it, stoplist, level+1))
+                       if (!toproot_helper(it, stoplist, donelist, level+1))
                                return false;
 
+               donelist.append(cursor);
                return true;
        }
 
@@ -204,10 +208,10 @@ struct FreduceHelper
                sig.expand();
                // log("  finding topological root in %s:\n", log_signal(sig));
                for (auto &c : sig.chunks) {
-                       RTLIL::SigSpec stoplist = sig;
+                       RTLIL::SigSpec stoplist = sig, donelist;
                        stoplist.remove(c);
                        // log("    testing %s as root:\n", log_signal(c));
-                       if (toproot_helper(c, stoplist, 0))
+                       if (toproot_helper(c, stoplist, donelist, 0))
                                return c;
                }
                return RTLIL::SigSpec();