From 3a148d76338217de4409cf12f2bec4cec5d8537f Mon Sep 17 00:00:00 2001
From: Lofty <lofty@yosyshq.com>
Date: Mon, 10 Aug 2026 12:58:29 +0100
Subject: [PATCH] synth_gowin: remove classic ABC mapping

---
 techlibs/gowin/synth_gowin.cc | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/techlibs/gowin/synth_gowin.cc b/techlibs/gowin/synth_gowin.cc
index d5ebdafea..aa8eec004 100644
--- a/techlibs/gowin/synth_gowin.cc
+++ b/techlibs/gowin/synth_gowin.cc
@@ -84,9 +84,6 @@ struct SynthGowinPass : public ScriptPass
 		log("    -noflatten\n");
 		log("        do not flatten design before synthesis\n");
 		log("\n");
-		log("    -retime\n");
-		log("        run 'abc' with '-dff -D 1' options\n");
-		log("\n");
 		log("    -nowidelut\n");
 		log("        do not use muxes to implement LUTs larger than LUT4s\n");
 		log("\n");
@@ -96,9 +93,6 @@ struct SynthGowinPass : public ScriptPass
 		log("    -noalu\n");
 		log("        do not use ALU cells\n");
 		log("\n");
-		log("    -noabc9\n");
-		log("        disable use of new ABC9 flow\n");
-		log("\n");
 		log("    -no-rw-check\n");
 		log("        marks all recognized read ports as \"return don't-care value on\n");
 		log("        read/write collision\" (same result as setting the no_rw_check\n");
@@ -121,7 +115,7 @@ struct SynthGowinPass : public ScriptPass
 	}
 
 	string top_opt, vout_file, json_file, family;
-	bool retime, nobram, nolutram, flatten, nodffe, strict_gw5a_dffs, nowidelut, abc9, noiopads, noalu, no_rw_check, setundef, nodsp;
+	bool nobram, nolutram, flatten, nodffe, strict_gw5a_dffs, nowidelut, noiopads, noalu, no_rw_check, setundef, nodsp;
 
 	void clear_flags() override
 	{
@@ -129,14 +123,12 @@ struct SynthGowinPass : public ScriptPass
 		top_opt = "-auto-top";
 		vout_file = "";
 		json_file = "";
-		retime = false;
 		flatten = true;
 		nobram = false;
 		nodffe = false;
 		strict_gw5a_dffs = false;
 		nolutram = false;
 		nowidelut = false;
-		abc9 = true;
 		noiopads = false;
 		noalu = false;
 		no_rw_check = false;
@@ -177,7 +169,7 @@ struct SynthGowinPass : public ScriptPass
 				continue;
 			}
 			if (args[argidx] == "-retime") {
-				retime = true;
+				// Removed: ABC9 does not support retiming.
 				continue;
 			}
 			if (args[argidx] == "-nobram") {
@@ -209,11 +201,11 @@ struct SynthGowinPass : public ScriptPass
 				continue;
 			}
 			if (args[argidx] == "-abc9") {
-				// removed, ABC9 is on by default.
+				// Removed: ABC9 is on by default.
 				continue;
 			}
 			if (args[argidx] == "-noabc9") {
-				abc9 = false;
+				// Removed: ABC9 can't be disabled.
 				continue;
 			}
 			if (args[argidx] == "-noiopads") {
@@ -330,8 +322,6 @@ struct SynthGowinPass : public ScriptPass
 				run("techmap -map +/techmap.v -map +/gowin/arith_map.v");
 			}
 			run("opt -fast");
-			if (retime || help_mode)
-				run("abc -dff -D 1", "(only if -retime)");
 			if (!noiopads || help_mode)
 				run("iopadmap -bits -inpad IBUF O:I -outpad OBUF I:O "
 					"-toutpad TBUF ~OEN:I:O -tinoutpad IOBUF ~OEN:O:I:IO", "(unless -noiopads)");
@@ -361,16 +351,11 @@ struct SynthGowinPass : public ScriptPass
 		if (check_label("map_luts"))
 		{
 			run("sort");
-			if (nowidelut && abc9) {
-				run("read_verilog -icells -lib -specify +/abc9_model.v");
+			run("read_verilog -icells -lib -specify +/abc9_model.v");
+			if (nowidelut) {
 				run("abc9 -maxlut 4 -W 500");
-			} else if (nowidelut && !abc9) {
-				run("abc -lut 4");
-			} else if (!nowidelut && abc9) {
-				run("read_verilog -icells -lib -specify +/abc9_model.v");
+			} else if (!nowidelut) {
 				run("abc9 -maxlut 8 -W 500");
-			} else if (!nowidelut && !abc9) {
-				run("abc -lut 4:8");
 			}
 			run("clean");
 		}