From eb17fbade5ef89983993d1e9d47da5f8a2fb32c3 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Sat, 16 Aug 2014 15:34:15 +0200
Subject: [PATCH] Added "opt -fast"

---
 passes/opt/opt.cc | 64 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 45 insertions(+), 19 deletions(-)

diff --git a/passes/opt/opt.cc b/passes/opt/opt.cc
index 33e1507bc..b6d36f0e3 100644
--- a/passes/opt/opt.cc
+++ b/passes/opt/opt.cc
@@ -37,7 +37,7 @@ struct OptPass : public Pass {
 		log("a series of trivial optimizations and cleanups. This pass executes the other\n");
 		log("passes in the following order:\n");
 		log("\n");
-		log("    opt_const\n");
+		log("    opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
 		log("    opt_share -nomux\n");
 		log("\n");
 		log("    do\n");
@@ -49,15 +49,26 @@ struct OptPass : public Pass {
 		log("        opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
 		log("    while <changed design>\n");
 		log("\n");
+		log("When called with -fast the following script is used instead:\n");
+		log("\n");
+		log("    do\n");
+		log("        opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
+		log("        opt_share\n");
+		log("        opt_rmdff\n");
+		log("        opt_clean [-purge]\n");
+		log("    while <changed design in opt_rmdff>\n");
+		log("\n");
 		log("Note: Options in square brackets (such as [-keepdc]) are passed through to\n");
 		log("the opt_* commands when given to 'opt'.\n");
 		log("\n");
+		log("\n");
 	}
 	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
 	{
 		std::string opt_clean_args;
 		std::string opt_const_args;
 		std::string opt_reduce_args;
+		bool fast_mode = false;
 
 		log_header("Executing OPT pass (performing simple optimizations).\n");
 		log_push();
@@ -89,32 +100,47 @@ struct OptPass : public Pass {
 				opt_const_args += " -keepdc";
 				continue;
 			}
+			if (args[argidx] == "-fast") {
+				fast_mode = true;
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
 
-		log_header("Optimizing in-memory representation of design.\n");
-		design->optimize();
-
-		Pass::call(design, "opt_const");
-		Pass::call(design, "opt_share -nomux");
-		while (1) {
-			OPT_DID_SOMETHING = false;
-			Pass::call(design, "opt_muxtree");
-			Pass::call(design, "opt_reduce" + opt_reduce_args);
-			Pass::call(design, "opt_share");
-			Pass::call(design, "opt_rmdff");
+		if (fast_mode)
+		{
+			while (1) {
+				Pass::call(design, "opt_const" + opt_const_args);
+				Pass::call(design, "opt_share");
+				OPT_DID_SOMETHING = false;
+				Pass::call(design, "opt_rmdff");
+				if (OPT_DID_SOMETHING == false)
+					break;
+				Pass::call(design, "opt_clean" + opt_clean_args);
+				log_header("Rerunning OPT passes. (Removed registers in this run.)\n");
+			}
 			Pass::call(design, "opt_clean" + opt_clean_args);
+		}
+		else
+		{
 			Pass::call(design, "opt_const" + opt_const_args);
-			if (OPT_DID_SOMETHING == false)
-				break;
-			log_header("Rerunning OPT passes. (Maybe there is more to do..)\n");
+			Pass::call(design, "opt_share -nomux");
+			while (1) {
+				OPT_DID_SOMETHING = false;
+				Pass::call(design, "opt_muxtree");
+				Pass::call(design, "opt_reduce" + opt_reduce_args);
+				Pass::call(design, "opt_share");
+				Pass::call(design, "opt_rmdff");
+				Pass::call(design, "opt_clean" + opt_clean_args);
+				Pass::call(design, "opt_const" + opt_const_args);
+				if (OPT_DID_SOMETHING == false)
+					break;
+				log_header("Rerunning OPT passes. (Maybe there is more to do..)\n");
+			}
 		}
 
-		log_header("Optimizing in-memory representation of design.\n");
-		design->optimize();
-
-		log_header("Finished OPT passes. (There is nothing left to do.)\n");
+		log_header(fast_mode ? "Finished fast OPT passes." : "Finished OPT passes. (There is nothing left to do.)\n");
 		log_pop();
 	}
 } OptPass;