cxxrtl: add -O6, a shortcut for running `proc; flatten`.

People judge a compiler backend by the first impression, and
the metric they judge it for is speed. -O6 does severely impact
debuggability, but it provides equally massive gains in performance,
so use it by default.

diff --git a/backends/cxxrtl/cxxrtl.cc b/backends/cxxrtl/cxxrtl.cc
index f5a8e18b5a7f21890158acb9392266322abfc090..eb769ac3f56e84321ac47f665b208597f65ee66f 100644 (file)
--- a/backends/cxxrtl/cxxrtl.cc
+++ b/backends/cxxrtl/cxxrtl.cc
@@ -424,6 +424,7 @@ struct CxxrtlWorker {
        bool localize_internal = false;
        bool localize_public = false;
        bool run_opt_clean_purge = false;
+       bool run_proc_flatten = false;
        bool max_opt_level = false;
 
        std::ostringstream f;
@@ -1929,8 +1930,12 @@ struct CxxrtlWorker {
        void prepare_design(RTLIL::Design *design)
        {
                bool has_sync_init, has_packed_mem;
+               log_push();
                check_design(design, has_sync_init, has_packed_mem);
-               if (has_sync_init) {
+               if (run_proc_flatten) {
+                       Pass::call(design, "proc");
+                       Pass::call(design, "flatten");
+               } else if (has_sync_init) {
                        // We're only interested in proc_init, but it depends on proc_prune and proc_clean, so call those
                        // in case they weren't already. (This allows `yosys foo.v -o foo.cc` to work.)
                        Pass::call(design, "proc_prune");
@@ -1945,13 +1950,13 @@ struct CxxrtlWorker {
                log_assert(!(has_sync_init || has_packed_mem));
                if (run_opt_clean_purge)
                        Pass::call(design, "opt_clean -purge");
-               log("\n");
+               log_pop();
                analyze_design(design);
        }
 };
 
 struct CxxrtlBackend : public Backend {
-       static const int DEFAULT_OPT_LEVEL = 5;
+       static const int DEFAULT_OPT_LEVEL = 6;
 
        CxxrtlBackend() : Backend("cxxrtl", "convert design to C++ RTL simulation") { }
        void help() YS_OVERRIDE
@@ -2138,6 +2143,9 @@ struct CxxrtlBackend : public Backend {
                log("    -O5\n");
                log("        like -O4, and run `opt_clean -purge` first.\n");
                log("\n");
+               log("    -O6\n");
+               log("        like -O5, and run `proc; flatten` first.\n");
+               log("\n");
        }
        void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
        {
@@ -2170,8 +2178,10 @@ struct CxxrtlBackend : public Backend {
                extra_args(f, filename, args, argidx);
 
                switch (opt_level) {
-                       case 5:
+                       case 6:
                                worker.max_opt_level = true;
+                               worker.run_proc_flatten = true;
+                       case 5:
                                worker.run_opt_clean_purge = true;
                        case 4:
                                worker.localize_public = true;