From 9c6d216a063452fcf0061b593b8ac278a39ff194 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Mon, 25 May 2020 07:32:27 -0700
Subject: [PATCH] tests: add test for abc9 -dff removing a redundant flop
 entirely

---
 tests/arch/xilinx/abc9_dff.ys | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tests/arch/xilinx/abc9_dff.ys b/tests/arch/xilinx/abc9_dff.ys
index c549e1fdc..e3889be05 100644
--- a/tests/arch/xilinx/abc9_dff.ys
+++ b/tests/arch/xilinx/abc9_dff.ys
@@ -116,4 +116,19 @@ design -load postopt
 select -assert-count 1 t:FDRE %co %a w:r %i
 
 
+design -reset
+read_verilog <<EOT
+module top(input clk, input a, b, output o);
+reg r1, r2;
+always @(posedge clk) begin
+    r1 <= a | b;
+    r2 <= ~(~a & ~b);
+end
+assign o = r1 | r2;
+endmodule
+EOT
+proc
+equiv_opt -assert -multiclock -map +/xilinx/cells_sim.v synth_xilinx -abc9 -dff -noiopad -noclkbuf
+
+
 logger -expect-no-warnings
-- 
2.30.2