From 63074ccb895c504d7a766b199ed7fad42a54e114 Mon Sep 17 00:00:00 2001
From: Peter Gadfort <peter.gadfort@gmail.com>
Date: Sat, 18 Jan 2025 10:27:10 -0700
Subject: [PATCH 1/3] add support for passing flatten -separator to flatten in
 synth

---
 techlibs/common/synth.cc | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index 74a484d59ae..a1ce1ae1b11 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -98,7 +98,7 @@ struct SynthPass : public ScriptPass {
 		log("\n");
 	}
 
-	string top_module, fsm_opts, memory_opts, abc;
+	string top_module, fsm_opts, memory_opts, abc, flatten_separator;
 	bool autotop, flatten, noalumacc, nofsm, noabc, noshare, flowmap, booth;
 	int lut;
 	std::vector<std::string> techmap_maps;
@@ -120,6 +120,7 @@ struct SynthPass : public ScriptPass {
 		booth = false;
 		abc = "abc";
 		techmap_maps.clear();
+		flatten_separator = "";
 	}
 
 	void execute(std::vector<std::string> args, RTLIL::Design *design) override
@@ -154,6 +155,8 @@ struct SynthPass : public ScriptPass {
 			}
 			if (args[argidx] == "-flatten") {
 				flatten = true;
+				if (design->scratchpad.count("flatten.separator"))
+					flatten_separator = design->scratchpad_get_string("flatten.separator");
 				continue;
 			}
 			if (args[argidx] == "-lut" && argidx + 1 < args.size()) {
@@ -239,8 +242,12 @@ struct SynthPass : public ScriptPass {
 
 		if (check_label("coarse")) {
 			run("proc");
-			if (flatten || help_mode)
-				run("flatten", "  (if -flatten)");
+			if (flatten || help_mode) {
+				if (!flatten_separator.empty())
+					run(stringf("flatten -separator %s", flatten_separator.c_str()), "  (if -flatten)");
+				else
+					run("flatten", "  (if -flatten)");
+			}
 			run("opt_expr");
 			run("opt_clean");
 			run("check");

From c4f90693aa1efe1e416dc385c0ee5e68840a5c31 Mon Sep 17 00:00:00 2001
From: Peter Gadfort <peter.gadfort@gmail.com>
Date: Sat, 18 Jan 2025 10:37:56 -0700
Subject: [PATCH 2/3] Revert "add support for passing flatten -separator to
 flatten in synth"

This reverts commit 63074ccb895c504d7a766b199ed7fad42a54e114.
---
 techlibs/common/synth.cc | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index a1ce1ae1b11..74a484d59ae 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -98,7 +98,7 @@ struct SynthPass : public ScriptPass {
 		log("\n");
 	}
 
-	string top_module, fsm_opts, memory_opts, abc, flatten_separator;
+	string top_module, fsm_opts, memory_opts, abc;
 	bool autotop, flatten, noalumacc, nofsm, noabc, noshare, flowmap, booth;
 	int lut;
 	std::vector<std::string> techmap_maps;
@@ -120,7 +120,6 @@ struct SynthPass : public ScriptPass {
 		booth = false;
 		abc = "abc";
 		techmap_maps.clear();
-		flatten_separator = "";
 	}
 
 	void execute(std::vector<std::string> args, RTLIL::Design *design) override
@@ -155,8 +154,6 @@ struct SynthPass : public ScriptPass {
 			}
 			if (args[argidx] == "-flatten") {
 				flatten = true;
-				if (design->scratchpad.count("flatten.separator"))
-					flatten_separator = design->scratchpad_get_string("flatten.separator");
 				continue;
 			}
 			if (args[argidx] == "-lut" && argidx + 1 < args.size()) {
@@ -242,12 +239,8 @@ struct SynthPass : public ScriptPass {
 
 		if (check_label("coarse")) {
 			run("proc");
-			if (flatten || help_mode) {
-				if (!flatten_separator.empty())
-					run(stringf("flatten -separator %s", flatten_separator.c_str()), "  (if -flatten)");
-				else
-					run("flatten", "  (if -flatten)");
-			}
+			if (flatten || help_mode)
+				run("flatten", "  (if -flatten)");
 			run("opt_expr");
 			run("opt_clean");
 			run("check");

From f0860459ac668a420915bca1628da5e634797f3a Mon Sep 17 00:00:00 2001
From: Peter Gadfort <peter.gadfort@gmail.com>
Date: Sat, 18 Jan 2025 10:45:19 -0700
Subject: [PATCH 3/3] add support for using scratchpad value for
 flatten.separator in flatten command

---
 passes/techmap/flatten.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/passes/techmap/flatten.cc b/passes/techmap/flatten.cc
index 619fa4a689d..3425509b15f 100644
--- a/passes/techmap/flatten.cc
+++ b/passes/techmap/flatten.cc
@@ -357,6 +357,9 @@ struct FlattenPass : public Pass {
 
 		FlattenWorker worker;
 
+		if (design->scratchpad.count("flatten.separator"))
+			worker.separator = design->scratchpad_get_string("flatten.separator");
+
 		size_t argidx;
 		for (argidx = 1; argidx < args.size(); argidx++) {
 			if (args[argidx] == "-wb") {