Add iteration limit to "opt_muxtree"

Signed-off-by: Clifford Wolf <clifford@clifford.at>

diff --git a/passes/opt/opt_muxtree.cc b/passes/opt/opt_muxtree.cc
index 87c7ce9b29c1c55c67dbfe38719358fa1d19d3e0..375697dc8dd5f2a44446c6c8414b641d9684df73 100644 (file)
--- a/passes/opt/opt_muxtree.cc
+++ b/passes/opt/opt_muxtree.cc
@@ -36,6 +36,7 @@ struct OptMuxtreeWorker
        RTLIL::Module *module;
        SigMap assign_map;
        int removed_count;
+       int glob_abort_cnt = 100000;
 
        struct bitinfo_t {
                bool seen_non_mux;
@@ -293,6 +294,9 @@ struct OptMuxtreeWorker
 
        void eval_mux_port(knowledge_t &knowledge, int mux_idx, int port_idx, bool do_replace_known, bool do_enable_ports, int abort_count)
        {
+               if (glob_abort_cnt == 0)
+                       return;
+
                muxinfo_t &muxinfo = mux2info[mux_idx];
 
                if (do_enable_ports)
@@ -315,7 +319,7 @@ struct OptMuxtreeWorker
                        knowledge.visited_muxes[m] = true;
                        parent_muxes.push_back(m);
                }
-               for (int m : parent_muxes)
+               for (int m : parent_muxes) {
                        if (root_enable_muxes.at(m))
                                continue;
                        else if (root_muxes.at(m)) {
@@ -327,6 +331,9 @@ struct OptMuxtreeWorker
                                        eval_mux(knowledge, m, false, do_enable_ports, abort_count - 1);
                        } else
                                eval_mux(knowledge, m, do_replace_known, do_enable_ports, abort_count);
+                       if (glob_abort_cnt == 0)
+                               return;
+               }
                for (int m : parent_muxes)
                        knowledge.visited_muxes[m] = false;
 
@@ -390,6 +397,12 @@ struct OptMuxtreeWorker
 
        void eval_mux(knowledge_t &knowledge, int mux_idx, bool do_replace_known, bool do_enable_ports, int abort_count)
        {
+               if (glob_abort_cnt == 0) {
+                       log("  Giving up (too many iterations)\n");
+                       return;
+               }
+               glob_abort_cnt--;
+
                muxinfo_t &muxinfo = mux2info[mux_idx];
 
                // set input ports to constants if we find known active or inactive signals
@@ -433,6 +446,9 @@ struct OptMuxtreeWorker
                                if (knowledge.known_inactive.at(portinfo.ctrl_sig))
                                        continue;
                        eval_mux_port(knowledge, mux_idx, port_idx, do_replace_known, do_enable_ports, abort_count);
+
+                       if (glob_abort_cnt == 0)
+                               return;
                }
        }