cxxrtl: order -On levels as localize, elide instead of the reverse.

Historically, elision was implemented before localization, so levels
with elision are lower than corresponding levels with localization.
This is unfortunate for two reasons:
  1. Elision is a logical subset of localization, since it equals to
     not giving a name to a temporary.
  2. "Localize" currently actually means "unbuffer and localize",
     and it would be useful to split those steps (at least for
     public wires) for improved design visibility.

diff --git a/backends/cxxrtl/cxxrtl_backend.cc b/backends/cxxrtl/cxxrtl_backend.cc
index 0ab8352c20deb7c6551cb5240de54612cf9a5d44..b1d89a7c21bf783738f919ffeba9315a4b945d1c 100644 (file)
--- a/backends/cxxrtl/cxxrtl_backend.cc
+++ b/backends/cxxrtl/cxxrtl_backend.cc
@@ -2490,16 +2490,16 @@ struct CxxrtlBackend : public Backend {
                log("        no optimization.\n");
                log("\n");
                log("    -O1\n");
-               log("        elide internal wires if possible.\n");
+               log("        localize internal wires if possible.\n");
                log("\n");
                log("    -O2\n");
-               log("        like -O1, and localize internal wires if possible.\n");
+               log("        like -O1, and elide internal wires if possible.\n");
                log("\n");
                log("    -O3\n");
-               log("        like -O2, and elide public wires not marked (*keep*) if possible.\n");
+               log("        like -O2, and localize public wires not marked (*keep*) if possible.\n");
                log("\n");
                log("    -O4\n");
-               log("        like -O3, and localize public wires not marked (*keep*) if possible.\n");
+               log("        like -O3, and elide public wires not marked (*keep*) if possible.\n");
                log("\n");
                log("    -g <level>\n");
                log("        set the debug level. the default is -g%d. higher debug levels provide\n", DEFAULT_DEBUG_LEVEL);
@@ -2568,16 +2568,16 @@ struct CxxrtlBackend : public Backend {
                switch (opt_level) {
                        // the highest level here must match DEFAULT_OPT_LEVEL
                        case 4:
-                               worker.localize_public = true;
+                               worker.elide_public = true;
                                YS_FALLTHROUGH
                        case 3:
-                               worker.elide_public = true;
+                               worker.localize_public = true;
                                YS_FALLTHROUGH
                        case 2:
-                               worker.localize_internal = true;
+                               worker.elide_internal = true;
                                YS_FALLTHROUGH
                        case 1:
-                               worker.elide_internal = true;
+                               worker.localize_internal = true;
                                YS_FALLTHROUGH
                        case 0:
                                break;