cxxrtl: add missing parts of commit 281c9685.

diff --git a/backends/cxxrtl/cxxrtl.cc b/backends/cxxrtl/cxxrtl.cc
index 549404184420f0875adc0936d6d7421398e85c62..998fe8dbca114a0df47a7e58ad52bbaad45a1c8a 100644 (file)
--- a/backends/cxxrtl/cxxrtl.cc
+++ b/backends/cxxrtl/cxxrtl.cc
@@ -513,7 +513,6 @@ struct CxxrtlWorker {
        bool elide_public = false;
        bool localize_internal = false;
        bool localize_public = false;
-       bool run_opt_clean_purge = false;
        bool run_proc_flatten = false;
        bool max_opt_level = false;
 
@@ -2046,7 +2045,7 @@ struct CxxrtlWorker {
                }
                if (has_feedback_arcs || has_buffered_wires) {
                        // Although both non-feedback buffered combinatorial wires and apparent feedback wires may be eliminated
-                       // by optimizing the design, if after `opt_clean -purge` there are any feedback wires remaining, it is very
+                       // by optimizing the design, if after `proc; flatten` there are any feedback wires remaining, it is very
                        // likely that these feedback wires are indicative of a true logic loop, so they get emphasized in the message.
                        const char *why_pessimistic = nullptr;
                        if (has_feedback_arcs)
@@ -2106,15 +2105,13 @@ struct CxxrtlWorker {
                if (has_sync_init || has_packed_mem)
                        check_design(design, has_sync_init, has_packed_mem);
                log_assert(!(has_sync_init || has_packed_mem));
-               if (run_opt_clean_purge)
-                       Pass::call(design, "opt_clean -purge");
                log_pop();
                analyze_design(design);
        }
 };
 
 struct CxxrtlBackend : public Backend {
-       static const int DEFAULT_OPT_LEVEL = 6;
+       static const int DEFAULT_OPT_LEVEL = 5;
 
        CxxrtlBackend() : Backend("cxxrtl", "convert design to C++ RTL simulation") { }
        void help() YS_OVERRIDE
@@ -2340,6 +2337,7 @@ struct CxxrtlBackend : public Backend {
                extra_args(f, filename, args, argidx);
 
                switch (opt_level) {
+                       // the highest level here must match DEFAULT_OPT_LEVEL
                        case 5:
                                worker.max_opt_level = true;
                                worker.run_proc_flatten = true;