From ad76625d4d828cb093b55aa9f5aae59b7ba9724f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miodrag=20Milanovi=C4=87?= <mmicko@gmail.com>
Date: Thu, 2 Oct 2025 11:27:44 +0200
Subject: [PATCH] gatemate: respect keep attribute and prevent crash with BEL
 set (#1566)

---
 himbaechel/uarch/gatemate/pack.cc | 20 ++++++++++++++++++++
 himbaechel/uarch/gatemate/pack.h  |  1 +
 2 files changed, 21 insertions(+)

diff --git a/himbaechel/uarch/gatemate/pack.cc b/himbaechel/uarch/gatemate/pack.cc
index 354e86d1..1ae99985 100644
--- a/himbaechel/uarch/gatemate/pack.cc
+++ b/himbaechel/uarch/gatemate/pack.cc
@@ -137,6 +137,8 @@ void GateMatePacker::optimize_lut()
         CellInfo &ci = *cell.second;
         if (!ci.type.in(id_CC_LUT1, id_CC_LUT2))
             continue;
+        if (ci.attrs.count(ctx->id("keep")))
+            continue;
         NetInfo *o_net = ci.getPort(id_O);
         if (!o_net) {
             count_cell(ci);
@@ -176,6 +178,8 @@ void GateMatePacker::optimize_mx()
         CellInfo &ci = *cell.second;
         if (!ci.type.in(id_CC_MX2, id_CC_MX4))
             continue;
+        if (ci.attrs.count(ctx->id("keep")))
+            continue;
         NetInfo *y_net = ci.getPort(id_Y);
         if (!y_net) {
             count_cell(ci);
@@ -220,6 +224,8 @@ void GateMatePacker::optimize_ff()
         CellInfo &ci = *cell.second;
         if (!ci.type.in(id_CC_DFF, id_CC_DLT))
             continue;
+        if (ci.attrs.count(ctx->id("keep")))
+            continue;
 
         NetInfo *q_net = ci.getPort(id_Q);
         if (!q_net) {
@@ -378,6 +384,19 @@ void GateMatePacker::repack_cpe()
     flush_cells();
 }
 
+void GateMatePacker::remove_double_constrained()
+{
+    for (auto &cell : ctx->cells) {
+        CellInfo &ci = *cell.second;
+        if (!ci.attrs.count(ctx->id("BEL")))
+            continue;
+        if (ci.cluster != ClusterId()) {
+            log_warning("Removing BEL attribute for cell '%s'.\n", ci.name.c_str(ctx));
+            ci.unsetAttr(ctx->id("BEL"));
+        }
+    }
+}
+
 void GateMateImpl::pack()
 {
     const ArchArgs &args = ctx->args;
@@ -404,6 +423,7 @@ void GateMateImpl::pack()
     packer.pack_cpe();
     packer.copy_clocks();
     packer.remove_constants();
+    packer.remove_double_constrained();
 
     if (forced_die != IdString()) {
         for (auto &cell : ctx->cells) {
diff --git a/himbaechel/uarch/gatemate/pack.h b/himbaechel/uarch/gatemate/pack.h
index 65ab9baf..7e247ffb 100644
--- a/himbaechel/uarch/gatemate/pack.h
+++ b/himbaechel/uarch/gatemate/pack.h
@@ -64,6 +64,7 @@ struct GateMatePacker
 
     void remove_constants();
     void remove_clocking();
+    void remove_double_constrained();
 
     void cleanup();
     void repack_cpe();