19 files changed, 481 insertions, 7 deletions
diff --git a/tests/memories/firrtl_938.v b/tests/memories/firrtl_938.v
new file mode 100644
index 000000000..af5efcd25
--- /dev/null
+++ b/tests/memories/firrtl_938.v
@@ -0,0 +1,22 @@
+module top
+(
+	input [7:0] data_a,
+	input [6:1] addr_a,
+	input we_a, clk,
+	output reg [7:0] q_a
+);
+	// Declare the RAM variable
+	reg [7:0] ram[63:0];
+
+	// Port A
+	always @ (posedge clk)
+	begin
+		if (we_a)
+		begin
+			ram[addr_a] <= data_a;
+			q_a <= data_a;
+		end
+			q_a <= ram[addr_a];
+	end
+
+endmodule
diff --git a/tests/simple/dff_init.v b/tests/simple/dff_init.v
index be947042e..375ea5c4d 100644
--- a/tests/simple/dff_init.v
+++ b/tests/simple/dff_init.v
@@ -40,3 +40,15 @@ module dff1a_test(n1, n1_inv, clk);
       n1 <= n1_inv;
   assign n1_inv = ~n1;
 endmodule
+
+module dff_test_997 (y, clk, wire4);
+// https://github.com/YosysHQ/yosys/issues/997
+   output wire [1:0] y;
+   input             clk;
+   input signed      wire4;
+   reg [1:0]  reg10 = 0;
+   always @(posedge clk) begin
+      reg10 <= wire4;
+   end
+   assign y = reg10;
+endmodule
diff --git a/tests/simple/forloops.v b/tests/simple/forloops.v
new file mode 100644
index 000000000..8665222d8
--- /dev/null
+++ b/tests/simple/forloops.v
@@ -0,0 +1,25 @@
+module forloops01 (input clk, a, b, output reg [3:0] p, q, x, y);
+	integer k;
+	always @(posedge clk) begin
+		for (k=0; k<2; k=k+1)
+			p[2*k +: 2] = {a, b} ^ {2{k}};
+		x <= k + {a, b};
+	end
+	always @* begin
+		for (k=0; k<4; k=k+1)
+			q[k] = {~a, ~b, a, b} >> k[1:0];
+		y = k - {a, b};
+	end
+endmodule
+
+module forloops02 (input clk, a, b, output reg [3:0] q, x, output [3:0] y);
+	integer k;
+	always @* begin
+		for (k=0; k<4; k=k+1)
+			q[k] = {~a, ~b, a, b} >> k[1:0];
+	end
+	always @* begin
+		x = k + {a, b};
+	end
+	assign y = k - {a, b};
+endmodule
diff --git a/tests/simple/localparam_attr.v b/tests/simple/localparam_attr.v
new file mode 100644
index 000000000..2ef76c71c
--- /dev/null
+++ b/tests/simple/localparam_attr.v
@@ -0,0 +1,11 @@
+module uut_localparam_attr (I, O);
+
+(* LOCALPARAM_ATTRIBUTE = "attribute_content" *)
+localparam WIDTH = 1;
+
+input  wire [WIDTH-1:0] I;
+output wire [WIDTH-1:0] O;
+
+assign O = I;
+
+endmodule
diff --git a/tests/simple/mem2reg.v b/tests/simple/mem2reg.v
index 9839fd4a8..100426785 100644
--- a/tests/simple/mem2reg.v
+++ b/tests/simple/mem2reg.v
@@ -92,3 +92,25 @@ module mem2reg_test5(input ctrl, output out);
 	assign out = bar[foo[0]];
 endmodule
 
+// ------------------------------------------------------
+
+module mem2reg_test6 (din, dout);
+        input   wire    [3:0] din;
+        output  reg     [3:0] dout;
+
+        reg [1:0] din_array  [1:0];
+        reg [1:0] dout_array [1:0];
+
+        always @* begin
+		din_array[0] = din[0 +: 2];
+		din_array[1] = din[2 +: 2];
+
+		dout_array[0] = din_array[0];
+		dout_array[1] = din_array[1];
+
+		{dout_array[0][1], dout_array[0][0]} = dout_array[0][0] + dout_array[1][0];
+
+		dout[0 +: 2] = dout_array[0];
+		dout[2 +: 2] = dout_array[1];
+        end
+endmodule
diff --git a/tests/simple/param_attr.v b/tests/simple/param_attr.v
new file mode 100644
index 000000000..34d63a34e
--- /dev/null
+++ b/tests/simple/param_attr.v
@@ -0,0 +1,11 @@
+module uut_param_attr (I, O);
+
+(* PARAMETER_ATTRIBUTE = "attribute_content" *)
+parameter WIDTH = 1;
+
+input  wire [WIDTH-1:0] I;
+output wire [WIDTH-1:0] O;
+
+assign O = I;
+
+endmodule
diff --git a/tests/simple/peepopt.v b/tests/simple/peepopt.v
new file mode 100644
index 000000000..b27b9fe57
--- /dev/null
+++ b/tests/simple/peepopt.v
@@ -0,0 +1,9 @@
+module peepopt_shiftmul_0 #(parameter N=3, parameter W=3) (input [N*W-1:0] i, input [$clog2(N)-1:0] s, output [W-1:0] o);
+assign o = i[s*W+:W];
+endmodule
+
+module peepopt_muldiv_0(input [1:0] i, output [1:0] o);
+wire [3:0] t;
+assign t = i * 3;
+assign o = t / 3;
+endmodule
diff --git a/tests/simple/wandwor.v b/tests/simple/wandwor.v
new file mode 100644
index 000000000..34404aa26
--- /dev/null
+++ b/tests/simple/wandwor.v
@@ -0,0 +1,36 @@
+module wandwor_test0 (A, B, C, D, X, Y, Z);
+	input A, B, C, D;
+	output wor X;
+	output wand Y;
+	output Z;
+
+	assign X = A, X = B, Y = C, Y = D;
+	foo foo_0 (C, D, X);
+	foo foo_1 (A, B, Y);
+	foo foo_2 (X, Y, Z);
+endmodule
+
+module wandwor_test1 (A, B, C, D, X, Y, Z);
+	input [3:0] A, B, C, D;
+	output wor [3:0] X;
+	output wand [3:0] Y;
+	output Z;
+
+	bar bar_inst (
+		.I0({A, B}),
+		.I1({B, A}),
+		.O({X, Y})
+	);
+
+	assign X = C, X = D;
+	assign Y = C, Y = D;
+	assign Z = ^{X,Y};
+endmodule
+
+module foo(input I0, I1, output O);
+	assign O = I0 ^ I1;
+endmodule
+
+module bar(input [7:0] I0, I1, output [7:0] O);
+	assign O = I0 + I1;
+endmodule
diff --git a/tests/simple/xfirrtl b/tests/simple/xfirrtl
index 50d693513..ba61a4476 100644
--- a/tests/simple/xfirrtl
+++ b/tests/simple/xfirrtl
@@ -16,6 +16,7 @@ operators.v	$pow
 partsel.v	drops modules
 process.v	drops modules
 realexpr.v	drops modules
+retime.v	Initial value (11110101) for (retime_test.ff) not supported
 scopes.v	original verilog issues ( -x where x isn't declared signed)
 sincos.v	$adff
 specify.v	no code (empty module generates error
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..2752ff8cc 100644
--- a/tests/simple_abc9/abc9.v
+++ b/tests/simple_abc9/abc9.v
@@ -142,3 +142,111 @@ assign b = ~a;
 (* keep *) reg d;
 always @* d <= &c;
 endmodule
+
+// Citation: https://github.com/alexforencich/verilog-ethernet
+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
+
+// Citation: https://github.com/alexforencich/verilog-ethernet
+// TODO: yosys -p "synth_xilinx -abc9 -top abc9_test022" abc9.v -q
+// returns before b4321a31
+//   Warning: Wire abc9_test022.\m_eth_payload_axis_tkeep [7] is used but has no
+//   driver.
+//   Warning: Wire abc9_test022.\m_eth_payload_axis_tkeep [3] is used but has no
+//   driver.
+module abc9_test022
+(
+    input  wire        clk,
+    input  wire        i,
+    output wire [7:0]  m_eth_payload_axis_tkeep
+);
+    reg [7:0]  m_eth_payload_axis_tkeep_reg = 8'd0;
+    assign m_eth_payload_axis_tkeep = m_eth_payload_axis_tkeep_reg;
+    always @(posedge clk)
+        m_eth_payload_axis_tkeep_reg <= i ? 8'hff : 8'h0f;
+endmodule
+
+// Citation: https://github.com/riscv/riscv-bitmanip
+// TODO: yosys -p "synth_xilinx -abc9 -top abc9_test023" abc9.v -q
+// returns before 14233843
+//   Warning: Wire abc9_test023.\dout [1] is used but has no driver.
+module abc9_test023 #(
+	parameter integer N = 2,
+	parameter integer M = 2
+) (
+	input [7:0] din,
+	output [M-1:0] dout
+);
+	wire [2*M-1:0] mask = {M{1'b1}};
+	assign dout = (mask << din[N-1:0]) >> M;
+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_ %%'"
diff --git a/tests/svinterfaces/runone.sh b/tests/svinterfaces/runone.sh
index 0adecc797..54cf5f2ec 100755
--- a/tests/svinterfaces/runone.sh
+++ b/tests/svinterfaces/runone.sh
@@ -11,12 +11,12 @@ echo "" > $STDERRFILE
 
 echo -n "Test: ${TESTNAME} -> "
 
-$PWD/../../yosys -p "read_verilog -sv ${TESTNAME}.sv ; hierarchy -check -top TopModule ; synth ; write_verilog ${TESTNAME}_syn.v" >> $STDOUTFILE >> $STDERRFILE
-$PWD/../../yosys -p "read_verilog -sv ${TESTNAME}_ref.v ; hierarchy -check -top TopModule ; synth ; write_verilog ${TESTNAME}_ref_syn.v" >> $STDOUTFILE >> $STDERRFILE
+set -e
 
-rm -f a.out reference_result.txt dut_result.txt
+$PWD/../../yosys -p "read_verilog -sv ${TESTNAME}.sv ; hierarchy -check -top TopModule ; synth ; write_verilog ${TESTNAME}_syn.v" >> $STDOUTFILE 2>> $STDERRFILE
+$PWD/../../yosys -p "read_verilog -sv ${TESTNAME}_ref.v ; hierarchy -check -top TopModule ; synth ; write_verilog ${TESTNAME}_ref_syn.v" >> $STDOUTFILE 2>> $STDERRFILE
 
-set -e
+rm -f a.out reference_result.txt dut_result.txt
 
 iverilog -g2012 ${TESTNAME}_syn.v
 iverilog -g2012 ${TESTNAME}_ref_syn.v
diff --git a/tests/tools/autotest.sh b/tests/tools/autotest.sh
index 86a90793e..920474a84 100755
--- a/tests/tools/autotest.sh
+++ b/tests/tools/autotest.sh
@@ -132,13 +132,13 @@ do
 		fn=$(basename $fn)
 		bn=$(basename $bn)
 
+		rm -f ${bn}_ref.fir
 		if [[ "$ext" == "v" ]]; then
 			egrep -v '^\s*`timescale' ../$fn > ${bn}_ref.${ext}
 		else
 			"$toolsdir"/../../yosys -f "$frontend $include_opts" -b "verilog" -o ${bn}_ref.v ../${fn}
 			frontend="verilog -noblackbox"
 		fi
-		rm -f ${bn}_ref.fir
 
 		if [ ! -f ../${bn}_tb.v ]; then
 			"$toolsdir"/../../yosys -f "$frontend $include_opts" -b "test_autotb $autotb_opts" -o ${bn}_tb.v ${bn}_ref.v
@@ -147,7 +147,8 @@ do
 		fi
 		if $genvcd; then sed -i 's,// \$dump,$dump,g' ${bn}_tb.v; fi
 		compile_and_run ${bn}_tb_ref ${bn}_out_ref ${bn}_tb.v ${bn}_ref.v $libs \
-					"$toolsdir"/../../techlibs/common/simlib.v
+					"$toolsdir"/../../techlibs/common/simlib.v \
+					"$toolsdir"/../../techlibs/common/simcells.v
 		if $genvcd; then mv testbench.vcd ${bn}_ref.vcd; fi
 
 		test_count=0
diff --git a/tests/various/chparam.sh b/tests/various/chparam.sh
new file mode 100644
index 000000000..9bb8d81db
--- /dev/null
+++ b/tests/various/chparam.sh
@@ -0,0 +1,52 @@
+#!/bin/bash
+
+trap 'echo "ERROR in chparam.sh" >&2; exit 1' ERR
+
+cat > chparam1.sv << "EOT"
+module top #(
+        parameter [31:0] X = 0
+) (
+        input [31:0] din,
+        output [31:0] dout
+);
+        assign dout = X-din;
+endmodule
+
+module top_props #(
+        parameter [31:0] X = 0
+) (
+        input [31:0] dout
+);
+        always @* assert (dout != X);
+endmodule
+
+bind top top_props #(.X(123456789)) props (.*);
+EOT
+
+cat > chparam2.sv << "EOT"
+module top #(
+	parameter [31:0] X = 0
+) (
+	input [31:0] din,
+	output [31:0] dout
+);
+	assign dout = X-din;
+	always @* assert (dout != 123456789);
+endmodule
+EOT
+
+if ../../yosys -q -p 'verific -sv chparam1.sv'; then
+	../../yosys -q -p 'verific -sv chparam1.sv; hierarchy -chparam X 123123123 -top top; prep -flatten' \
+			-p 'sat -verify -prove-asserts -show-ports -set din[0] 1' \
+			-p 'sat -falsify -prove-asserts -show-ports -set din[0] 0'
+
+	../../yosys -q -p 'verific -sv chparam2.sv; hierarchy -chparam X 123123123 -top top; prep -flatten' \
+			-p 'sat -verify -prove-asserts -show-ports -set din[0] 1' \
+			-p 'sat -falsify -prove-asserts -show-ports -set din[0] 0'
+fi
+../../yosys -q -p 'read_verilog -sv chparam2.sv; hierarchy -chparam X 123123123 -top top; prep -flatten' \
+		-p 'sat -verify -prove-asserts -show-ports -set din[0] 1' \
+		-p 'sat -falsify -prove-asserts -show-ports -set din[0] 0'
+
+rm chparam1.sv
+rm chparam2.sv
diff --git a/tests/various/opt_rmdff.v b/tests/various/opt_rmdff.v
new file mode 100644
index 000000000..b1c06703c
--- /dev/null
+++ b/tests/various/opt_rmdff.v
@@ -0,0 +1,50 @@
+module opt_rmdff_test (input C, input D, input E, output [29:0] Q);
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove0 (.CLK(C), .D(D), .EN(1'b0), .Q(Q[0])); // EN is never active
+(* init = "1'b1" *) wire Q1; assign Q[1] = Q1;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove1 (.CLK(C), .D(D), .EN(1'b0), .Q(Q1)); // EN is never active
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove2 (.CLK(C), .D(D), .EN(1'bx), .Q(Q[2])); // EN is don't care
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) keep3 (.CLK(C), .D(D), .EN(1'b1), .Q(Q[3])); // EN is always active
+(* init = "1'b0" *) wire Q4; assign Q[4] = Q4;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(0), .EN_POLARITY(1)) keep4 (.CLK(C), .D(D), .EN(1'b1), .Q(Q4)); // EN is always active
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) remove5 (.CLK(C), .D(D), .EN(1'b1), .Q(Q[5])); // EN is never active
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) remove6 (.CLK(C), .D(D), .EN(1'bx), .Q(Q[6])); // EN is don't care
+(* init = "1'b0" *) wire Q7; assign Q[7] = Q7;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(0), .EN_POLARITY(0)) keep7 (.CLK(C), .D(D), .EN(E), .Q(Q7)); // EN is non constant
+
+\$_DFFE_PP_ remove8 (.C(C), .D(D), .E(1'b0), .Q(Q[8])); // EN is never active
+(* init = "1'b1" *) wire Q9; assign Q[9] = Q9;
+\$_DFFE_PP_ remove9 (.C(C), .D(D), .E(1'b0), .Q(Q9)); // EN is never active
+\$_DFFE_PP_ remove10 (.C(C), .D(D), .E(1'bx), .Q(Q[10])); // EN is don't care
+\$_DFFE_PP_ keep11 (.C(C), .D(D), .E(1'b1), .Q(Q[11])); // EN is always active
+(* init = "1'b0" *) wire Q12; assign Q[12] = Q12;
+\$_DFFE_PP_ keep12 (.C(C), .D(D), .E(1'b1), .Q(Q12)); // EN is always active
+
+\$_DFFE_NN_ remove13 (.C(C), .D(D), .E(1'b1), .Q(Q[13])); // EN is never active
+(* init = "1'b1" *) wire Q14; assign Q[14] = Q14;
+\$_DFFE_NN_ remove14 (.C(C), .D(D), .E(1'b1), .Q(Q14)); // EN is never active
+\$_DFFE_NN_ remove15 (.C(C), .D(D), .E(1'bx), .Q(Q[15])); // EN is don't care
+\$_DFFE_NN_ keep16 (.C(C), .D(D), .E(1'b0), .Q(Q[16])); // EN is always active
+(* init = "1'b0" *) wire Q17; assign Q[17] = Q17;
+\$_DFFE_NN_ keep17 (.C(C), .D(D), .E(1'b0), .Q(Q17)); // EN is always active
+
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove18 (.CLK(1'b0), .D(D), .EN(E), .Q(Q[18])); // CLK is constant
+(* init = "1'b1" *) wire Q19; assign Q[19] = Q19;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove19 (.CLK(1'b1), .D(D), .EN(E), .Q(Q19)); // CLK is constant
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove20 (.CLK(C), .D(1'bx), .EN(E), .Q(Q[20])); // D is undriven, Q has no initial value
+(* init = "1'b0" *) wire Q21; assign Q[21] = Q21;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) keep21 (.CLK(C), .D(1'bx), .EN(E), .Q(Q21)); // D is undriven, Q has initial value
+//\$dffe #(.WIDTH(1), .CLK_POLARITY(0), .EN_POLARITY(1)) remove22 (.CLK(C), .D(1'b0), .EN(1'b1), .Q(Q[22])); // D is constant, no initial Q value, EN is always active
+//                                                                                                           // (TODO, Q starts with 1'bx and becomes 1'b0)
+(* init = "1'b0" *) wire Q23; assign Q[23] = Q23;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) noenable23 (.CLK(C), .D(1'b0), .EN(1'b1), .Q(Q23)); // D is constant, initial Q value same as D, EN is always active
+(* init = "1'b1" *) wire Q24; assign Q[24] = Q24;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) keep24 (.CLK(C), .D(1'b0), .EN(1'b0), .Q(Q24)); // D is constant, initial Q value NOT same as D, EN is always active
+(* init = "1'b1" *) wire Q25; assign Q[25] = Q25;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) remove25 (.CLK(C), .D(1'b0), .EN(1'b1), .Q(Q25)); // D is constant, EN is never active
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) remove26 (.CLK(C), .D(Q[26]), .EN(1'b1), .Q(Q[26])); // D is Q, EN is always active
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) remove27 (.CLK(C), .D(Q[27]), .EN(1'b1), .Q(Q[27])); // D is Q, EN is never active, but no initial value
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(0)) remove28 (.CLK(C), .D(Q[28]), .EN(E), .Q(Q[28])); // EN is nonconst, but no initial value
+(* init = "1'b1" *) wire Q29; assign Q[29] = Q29;
+\$dffe #(.WIDTH(1), .CLK_POLARITY(1), .EN_POLARITY(1)) keep29 (.CLK(C), .D(Q[29]), .EN(1'b1), .Q(Q29)); // EN is always active, but with initial value
+
+endmodule
diff --git a/tests/various/opt_rmdff.ys b/tests/various/opt_rmdff.ys
new file mode 100644
index 000000000..081f81782
--- /dev/null
+++ b/tests/various/opt_rmdff.ys
@@ -0,0 +1,26 @@
+read_verilog -icells opt_rmdff.v
+prep
+design -stash gold
+read_verilog -icells opt_rmdff.v
+proc
+opt_rmdff
+
+select -assert-count 0 c:remove*
+select -assert-min 7 c:keep*
+select -assert-count 0  t:$dffe 7:$_DFFE_* %u c:noenable* %i
+
+design -stash gate
+
+design -import gold -as gold
+design -import gate -as gate
+
+equiv_make gold gate equiv
+hierarchy -top equiv
+equiv_simple -undef
+equiv_status -assert
+
+design -load gold
+stat
+
+design -load gate
+stat
diff --git a/tests/various/specify.v b/tests/various/specify.v
new file mode 100644
index 000000000..afc421da8
--- /dev/null
+++ b/tests/various/specify.v
@@ -0,0 +1,30 @@
+module test (
+	input EN, CLK,
+	input [3:0] D,
+	output reg [3:0] Q
+);
+	always @(posedge CLK)
+		if (EN) Q <= D;
+
+	specify
+		if (EN) (CLK *> (Q : D)) = (1, 2:3:4);
+		$setup(D, posedge CLK &&& EN, 5);
+		$hold(posedge CLK, D &&& EN, 6);
+	endspecify
+endmodule
+
+module test2 (
+	input A, B,
+	output Q
+);
+	xor (Q, A, B);
+	specify
+		//specparam T_rise = 1;
+		//specparam T_fall = 2;
+		`define T_rise 1
+		`define T_fall 2
+		(A => Q) = (`T_rise,`T_fall);
+		//(B => Q) = (`T_rise+`T_fall)/2.0;
+		(B => Q) = 1.5;
+	endspecify
+endmodule
diff --git a/tests/various/specify.ys b/tests/various/specify.ys
new file mode 100644
index 000000000..a5ca07219
--- /dev/null
+++ b/tests/various/specify.ys
@@ -0,0 +1,56 @@
+read_verilog -specify specify.v
+prep
+cd test
+select t:$specify2 -assert-count 0
+select t:$specify3 -assert-count 1
+select t:$specrule -assert-count 2
+cd test2
+select t:$specify2 -assert-count 2
+select t:$specify3 -assert-count 0
+select t:$specrule -assert-count 0
+cd
+write_verilog specify.out
+design -stash gold
+
+read_verilog -specify specify.out
+prep
+cd test
+select t:$specify2 -assert-count 0
+select t:$specify3 -assert-count 1
+select t:$specrule -assert-count 2
+cd test2
+select t:$specify2 -assert-count 2
+select t:$specify3 -assert-count 0
+select t:$specrule -assert-count 0
+cd
+design -stash gate
+
+design -copy-from gold -as gold test
+design -copy-from gate -as gate test
+rename -hide
+rename -enumerate -pattern A_% t:$specify3
+rename -enumerate -pattern B_% t:$specrule r:TYPE=$setup %i
+rename -enumerate -pattern C_% t:$specrule r:TYPE=$hold %i
+select n:A_* -assert-count 2
+select n:B_* -assert-count 2
+select n:C_* -assert-count 2
+equiv_make gold gate equiv
+hierarchy -top equiv
+equiv_struct
+equiv_induct -seq 5
+equiv_status -assert
+design -reset
+
+design -copy-from gold -as gold test2
+design -copy-from gate -as gate test2
+rename -hide
+rename -enumerate -pattern A_% t:$specify2 r:T_RISE_TYP=1 %i
+rename -enumerate -pattern B_% t:$specify2 n:A_* %d
+select n:A_* -assert-count 2
+select n:B_* -assert-count 2
+equiv_make gold gate equiv
+hierarchy -top equiv
+equiv_struct
+equiv_induct -seq 5
+equiv_status -assert
+design -reset