From eec314e2621d3d055d7810f4b7e573a99e0239b2 Mon Sep 17 00:00:00 2001
From: Eddie Hung <eddie@fpgeh.com>
Date: Wed, 24 Apr 2019 21:06:53 -0700
Subject: [PATCH] Remove topo sort no-loop assertion, with test

---
 backends/aiger/xaiger.cc      | 13 -------
 tests/simple_abc9/abc.box     |  2 +
 tests/simple_abc9/abc9.v      | 73 +++++++++++++++++++++++++++++++++++
 tests/simple_abc9/run-test.sh |  2 +-
 4 files changed, 76 insertions(+), 14 deletions(-)
 create mode 100644 tests/simple_abc9/abc.box

diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 504a66086..f9d874e2d 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -294,20 +294,7 @@ struct XAigerWriter
 					for (auto user_cell : it.second)
 						toposort.edge(driver_cell, user_cell);
 
-#ifndef NDEBUG
-			toposort.analyze_loops = true;
-#endif
 			toposort.sort();
-#ifndef NDEBUG
-			for (auto &it : toposort.loops) {
-				log("  loop");
-				for (auto cell : it)
-					log(" %s", log_id(cell));
-				log("\n");
-			}
-#endif
-			log_assert(!toposort.found_loops);
-
 			for (auto cell_name : toposort.sorted) {
 				RTLIL::Cell *cell = module->cell(cell_name);
 				RTLIL::Module* box_module = module->design->module(cell->type);
diff --git a/tests/simple_abc9/abc.box b/tests/simple_abc9/abc.box
new file mode 100644
index 000000000..a8801d807
--- /dev/null
+++ b/tests/simple_abc9/abc.box
@@ -0,0 +1,2 @@
+MUXF8 1 0 3 1
+1 1 1
diff --git a/tests/simple_abc9/abc9.v b/tests/simple_abc9/abc9.v
index f37d975ff..fb5b759fb 100644
--- a/tests/simple_abc9/abc9.v
+++ b/tests/simple_abc9/abc9.v
@@ -142,3 +142,76 @@ assign b = ~a;
 (* keep *) reg d;
 always @* d <= &c;
 endmodule
+
+module abc9_test021(clk, rst, s_eth_hdr_valid, s_eth_hdr_ready, s_eth_dest_mac, s_eth_src_mac, s_eth_type, s_eth_payload_axis_tdata, s_eth_payload_axis_tkeep, s_eth_payload_axis_tvalid, s_eth_payload_axis_tready, s_eth_payload_axis_tlast, s_eth_payload_axis_tid, s_eth_payload_axis_tdest, s_eth_payload_axis_tuser, m_eth_hdr_valid, m_eth_hdr_ready, m_eth_dest_mac, m_eth_src_mac, m_eth_type, m_eth_payload_axis_tdata, m_eth_payload_axis_tkeep, m_eth_payload_axis_tvalid, m_eth_payload_axis_tready, m_eth_payload_axis_tlast, m_eth_payload_axis_tid, m_eth_payload_axis_tdest, m_eth_payload_axis_tuser);
+  input clk;
+  output [47:0] m_eth_dest_mac;
+  input m_eth_hdr_ready;
+  output m_eth_hdr_valid;
+  output [7:0] m_eth_payload_axis_tdata;
+  output [7:0] m_eth_payload_axis_tdest;
+  output [7:0] m_eth_payload_axis_tid;
+  output m_eth_payload_axis_tkeep;
+  output m_eth_payload_axis_tlast;
+  input m_eth_payload_axis_tready;
+  output m_eth_payload_axis_tuser;
+  output m_eth_payload_axis_tvalid;
+  output [47:0] m_eth_src_mac;
+  output [15:0] m_eth_type;
+  input rst;
+  input [191:0] s_eth_dest_mac;
+  output [3:0] s_eth_hdr_ready;
+  input [3:0] s_eth_hdr_valid;
+  input [31:0] s_eth_payload_axis_tdata;
+  input [31:0] s_eth_payload_axis_tdest;
+  input [31:0] s_eth_payload_axis_tid;
+  input [3:0] s_eth_payload_axis_tkeep;
+  input [3:0] s_eth_payload_axis_tlast;
+  output [3:0] s_eth_payload_axis_tready;
+  input [3:0] s_eth_payload_axis_tuser;
+  input [3:0] s_eth_payload_axis_tvalid;
+  input [191:0] s_eth_src_mac;
+  input [63:0] s_eth_type;
+  (* keep *)
+  wire [0:0] grant, request;
+  wire a;
+  not u0 (
+    a,
+    grant[0]
+  );
+  and u1  (
+    request[0],
+    s_eth_hdr_valid[0],
+    a
+  );
+  (* keep *)
+  MUXF8 u2  (
+    .I0(1'bx),
+    .I1(1'bx),
+    .O(o),
+    .S(1'bx)
+  );
+  arbiter  arb_inst (
+    .acknowledge(acknowledge),
+    .clk(clk),
+    .grant(grant),
+    .grant_encoded(grant_encoded),
+    .grant_valid(grant_valid),
+    .request(request),
+    .rst(rst)
+  );
+endmodule
+
+module arbiter (clk, rst, request, acknowledge, grant, grant_valid, grant_encoded);
+  input [3:0] acknowledge;
+  input clk;
+  output [3:0] grant;
+  output [1:0] grant_encoded;
+  output grant_valid;
+  input [3:0] request;
+  input rst;
+endmodule
+
+(* abc_box_id=1 *)
+module MUXF8(input I0, I1, S, output O);
+endmodule
diff --git a/tests/simple_abc9/run-test.sh b/tests/simple_abc9/run-test.sh
index 97f284378..4935d41ad 100755
--- a/tests/simple_abc9/run-test.sh
+++ b/tests/simple_abc9/run-test.sh
@@ -19,4 +19,4 @@ fi
 
 cp ../simple/*.v .
 DOLLAR='?'
-exec ${MAKE:-make} -f ../tools/autotest.mk $seed *.v EXTRA_FLAGS="-p 'hierarchy; synth -run coarse; techmap; opt -full; abc9 -lut 4; stat; check -assert; select -assert-none t:${DOLLAR}_NOT_ t:${DOLLAR}_AND_ %%'"
+exec ${MAKE:-make} -f ../tools/autotest.mk $seed *.v EXTRA_FLAGS="-p 'hierarchy; synth -run coarse; opt -full; techmap; abc9 -lut 4 -box ../abc.box; stat; check -assert; select -assert-none t:${DOLLAR}_NOT_ t:${DOLLAR}_AND_ %%'"
-- 
2.30.2