From: Clifford Wolf <clifford@clifford.at>
Date: Wed, 19 Mar 2014 09:05:01 +0000 (+0100)
Subject: Fixed performance problem in opt_mux with nets driven by many conflicting drivers
X-Git-Tag: yosys-0.3.0~36
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9a34486bfbc8780d9a3af3164e99977e44d2a65f;p=yosys.git

Fixed performance problem in opt_mux with nets driven by many conflicting drivers
---

diff --git a/passes/opt/opt_muxtree.cc b/passes/opt/opt_muxtree.cc
index 47100869c..3292a46c8 100644
--- a/passes/opt/opt_muxtree.cc
+++ b/passes/opt/opt_muxtree.cc
@@ -309,13 +309,17 @@ struct OptMuxtreeWorker
 		if (port_idx < int(muxinfo.ports.size())-1 && !muxinfo.ports[port_idx].const_activated)
 			knowledge.known_active.push_back(muxinfo.ports[port_idx].ctrl_sigs);
 
+		std::vector<int> parent_muxes;
 		for (int m : muxinfo.ports[port_idx].input_muxes) {
 			if (knowledge.visited_muxes.count(m) > 0)
 				continue;
 			knowledge.visited_muxes.insert(m);
+			parent_muxes.push_back(m);
+		}
+		for (int m : parent_muxes)
 			eval_mux(knowledge, m);
+		for (int m : parent_muxes)
 			knowledge.visited_muxes.erase(m);
-		}
 
 		if (port_idx < int(muxinfo.ports.size())-1 && !muxinfo.ports[port_idx].const_activated)
 			knowledge.known_active.pop_back();
@@ -393,6 +397,7 @@ struct OptMuxtreeWorker
 	void eval_root_mux(int mux_idx)
 	{
 		knowledge_t knowledge;
+		knowledge.visited_muxes.insert(mux_idx);
 		eval_mux(knowledge, mux_idx);
 	}
 };