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-rw-r--r--passes/sat/freduce.cc12
1 files changed, 8 insertions, 4 deletions
diff --git a/passes/sat/freduce.cc b/passes/sat/freduce.cc
index 00968c73..d57fdd32 100644
--- 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();