From 2c94ca85d9421634d2a7a14094f5ec1a0b24180d Mon Sep 17 00:00:00 2001
From: Jannis Harder <me@jix.one>
Date: Tue, 7 Oct 2025 17:35:32 +0200
Subject: [PATCH] abc_new: Avoid bufnorm helper cell churn

We were performing the helper passes `abc9_ops -replace_zbufs` and
`abc9_ops -restore_zbufs` for every module, but those passes act on the
full design (and can't be applied entirely selectively due to entering
and leaving bufnorm).

This lead to an explosive creation of a lot of redundant bufnorm helper
cells that would have been cleaned up by `clean` but that never ran.
Instead we now run each helper pass once, one before and one after
iterating over the selected modules. This limits the number of bufnorm
helper cells.
---
 passes/cmds/portarcs.cc    |  2 +-
 passes/techmap/abc9_ops.cc |  2 +-
 passes/techmap/abc_new.cc  | 11 +++++++----
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/passes/cmds/portarcs.cc b/passes/cmds/portarcs.cc
index 8cc5d1236..4344d6cb2 100644
--- a/passes/cmds/portarcs.cc
+++ b/passes/cmds/portarcs.cc
@@ -125,7 +125,7 @@ struct PortarcsPass : Pass {
 
 				for (auto cell : m->cells())
 				// Ignore all bufnorm helper cells
-				if (!cell->type.in(ID($buf), ID($input_port), ID($connect))) {
+				if (!cell->type.in(ID($buf), ID($input_port), ID($connect), ID($tribuf))) {
 					auto tdata = tinfo.find(cell->type);
 					if (tdata == tinfo.end())
 						log_cmd_error("Missing timing data for module '%s'.\n", log_id(cell->type));
diff --git a/passes/techmap/abc9_ops.cc b/passes/techmap/abc9_ops.cc
index 2e762d7b9..373d5d15e 100644
--- a/passes/techmap/abc9_ops.cc
+++ b/passes/techmap/abc9_ops.cc
@@ -1605,6 +1605,7 @@ static void replace_zbufs(Design *design)
 
 		mod->bufNormalize();
 	}
+	design->bufNormalize(false);
 }
 
 
@@ -1624,7 +1625,6 @@ static void restore_zbufs(Design *design)
 			mod->addBuf(NEW_ID, Const(State::Sz, GetSize(sig_y)), sig_y);
 			mod->remove(cell);
 		}
-		mod->bufNormalize();
 	}
 }
 
diff --git a/passes/techmap/abc_new.cc b/passes/techmap/abc_new.cc
index c48295916..21ffa075b 100644
--- a/passes/techmap/abc_new.cc
+++ b/passes/techmap/abc_new.cc
@@ -141,7 +141,11 @@ struct AbcNewPass : public ScriptPass {
 				selected_modules = order_modules(active_design,
 												 active_design->selected_whole_modules_warn());
 				active_design->push_empty_selection();
-			} else {
+			}
+
+			run("abc9_ops -replace_zbufs");
+
+			if (help_mode) {
 				selected_modules = {nullptr};
 				run("foreach module in selection");
 			}
@@ -169,13 +173,10 @@ struct AbcNewPass : public ScriptPass {
 				}
 
 				run(stringf("  abc9_ops -write_box %s/input.box", tmpdir));
-				run("  abc9_ops -replace_zbufs");
 				run(stringf("  write_xaiger2 -mapping_prep -map2 %s/input.map2 %s/input.xaig", tmpdir, tmpdir));
 				run(stringf("  abc9_exe %s -cwd %s -box %s/input.box", exe_options, tmpdir, tmpdir));
 				run(stringf("  read_xaiger2 -sc_mapping -module_name %s -map2 %s/input.map2 %s/output.aig",
 							modname.c_str(), tmpdir.c_str(), tmpdir.c_str()));
-				run("  abc9_ops -restore_zbufs");
-
 				if (!help_mode && mod->has_attribute(ID(abc9_script))) {
 					if (script_save.empty())
 						active_design->scratchpad_unset("abc9.script");
@@ -196,6 +197,8 @@ struct AbcNewPass : public ScriptPass {
 				}
 			}
 
+			run("abc9_ops -restore_zbufs");
+
 			if (!help_mode) {
 				active_design->pop_selection();
 			}