From b87327d1b9a0ec0c8b62694cb3697dcda1665ee2 Mon Sep 17 00:00:00 2001
From: "N. Engelhardt" <nak@yosyshq.com>
Date: Fri, 12 Apr 2024 13:38:33 +0200
Subject: [PATCH 1/2] fix hierarchy -generate mode handling of  cells

---
 passes/hierarchy/hierarchy.cc       |  2 +-
 tests/various/hierarchy_generate.ys | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 tests/various/hierarchy_generate.ys

diff --git a/passes/hierarchy/hierarchy.cc b/passes/hierarchy/hierarchy.cc
index 6fcda5d76..3ef04616f 100644
--- a/passes/hierarchy/hierarchy.cc
+++ b/passes/hierarchy/hierarchy.cc
@@ -47,7 +47,7 @@ void generate(RTLIL::Design *design, const std::vector<std::string> &celltypes,
 	{
 		if (design->module(cell->type) != nullptr)
 			continue;
-		if (cell->type.begins_with("$__"))
+		if (cell->type.begins_with("$") && !cell->type.begins_with("$__"))
 			continue;
 		for (auto &pattern : celltypes)
 			if (patmatch(pattern.c_str(), RTLIL::unescape_id(cell->type).c_str()))
diff --git a/tests/various/hierarchy_generate.ys b/tests/various/hierarchy_generate.ys
new file mode 100644
index 000000000..a4dc87a86
--- /dev/null
+++ b/tests/various/hierarchy_generate.ys
@@ -0,0 +1,19 @@
+read_verilog -icells <<EOF
+module top(input [2:0] a, input [2:0] b, output [2:0] y);
+
+sub sub_i (.a(a[0]), .b(b[0]), .y(y[0]));
+
+unknown_sub sub_ii (.a(a[1]), .b(b[1]), .y(y[1]));
+
+$__dunder_sub sub_iii (.a(a[2]), .b(b[2]), .y(y[2]));
+
+endmodule
+
+module sub(input a, input b, output y);
+    assign y = a ^ b;
+endmodule
+EOF
+hierarchy -generate unknown_sub i:a i:b o:y
+hierarchy -generate $__dunder_sub i:a i:b o:y
+hierarchy -top top -check
+check -assert

From e8ec19c273420c0cc5517bb5e584705ef17b5aa6 Mon Sep 17 00:00:00 2001
From: "N. Engelhardt" <nak@yosyshq.com>
Date: Fri, 12 Apr 2024 13:51:06 +0200
Subject: [PATCH 2/2] add command that should not have any effect to hierarchy
 -generate test (this documents the current behavior, not sure if it is
 desired functionality)

---
 tests/various/hierarchy_generate.ys | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/various/hierarchy_generate.ys b/tests/various/hierarchy_generate.ys
index a4dc87a86..9c01afb64 100644
--- a/tests/various/hierarchy_generate.ys
+++ b/tests/various/hierarchy_generate.ys
@@ -15,5 +15,6 @@ endmodule
 EOF
 hierarchy -generate unknown_sub i:a i:b o:y
 hierarchy -generate $__dunder_sub i:a i:b o:y
+hierarchy -generate $xor i:A i:B o:Y # this one is ignored
 hierarchy -top top -check
 check -assert