From 8b928a8274f8ad02943402f0d73c2894e5f0c2be Mon Sep 17 00:00:00 2001
From: Alain Dargelas <alain@silimate.com>
Date: Tue, 11 Mar 2025 10:26:02 -0700
Subject: [PATCH] Fixes to enable keep_hierarchy

---
 kernel/cost.cc                     | 13 ++++++++++++-
 passes/hierarchy/keep_hierarchy.cc |  4 +++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/kernel/cost.cc b/kernel/cost.cc
index 5d897ab7a..62710130a 100644
--- a/kernel/cost.cc
+++ b/kernel/cost.cc
@@ -101,6 +101,13 @@ static bool is_free(RTLIL::IdString type)
 	  type.in(ID($specrule), ID($specify2), ID($specify3)));
 }
 
+static bool is_mem(RTLIL::IdString type)
+{
+	return (
+		// tags
+		type.in(ID($memrd), ID($memrd_v2), ID($memwr), ID($memwr_v2), ID($meminit), ID($meminit_v2), ID($mem), ID($mem_v2)));
+}
+
 unsigned int max_inp_width(RTLIL::Cell *cell)
 {
 	unsigned int max = 0;
@@ -186,8 +193,12 @@ unsigned int CellCosts::get(RTLIL::Cell *cell)
 	} else if (is_free(cell->type)) {
 		log_debug("%s is free\n", cell->name.c_str());
 		return 0;
+	} else if (is_mem(cell->type)) {
+		// SILIMATE: Memory cells have no bearing on cross module optimizations
+		log_debug("%s is mem\n", cell->name.c_str());
+		return 1;
 	}
-	// TODO: $fsm $mem.* $macc
+	// TODO: $fsm $macc
 	// ignored: $pow
 
 	log_warning("Can't determine cost of %s cell (%d parameters).\n", log_id(cell->type), GetSize(cell->parameters));
diff --git a/passes/hierarchy/keep_hierarchy.cc b/passes/hierarchy/keep_hierarchy.cc
index 9d77b5239..21f8094b3 100644
--- a/passes/hierarchy/keep_hierarchy.cc
+++ b/passes/hierarchy/keep_hierarchy.cc
@@ -42,7 +42,9 @@ struct ThresholdHierarchyKeeping {
 			return 0;
 
 		if (module->get_blackbox_attribute())
-			log_error("Missing cost information on instanced blackbox %s\n", log_id(module));
+			// SILIMATE: Blackboxes have no bearing on cross module optimizations
+			// log_error("Missing cost information on instanced blackbox %s\n", log_id(module));
+			return 1;
 
 		if (done.count(module))
 			return done.at(module);