Merge pull request #1130 from YosysHQ/eddie/fix710

memory_dff: walk through more than one mux for computing read enable

3 files changed, 33 insertions, 6 deletions

diff --git a/passes/memory/memory_dff.cc b/passes/memory/memory_dff.cc
index 220d29295..5215cce44 100644
--- a/passes/memory/memory_dff.cc
+++ b/passes/memory/memory_dff.cc
@@ -182,11 +182,17 @@ struct MemoryDffWorker
 
 		if (mux_cells_a.count(sig_data) || mux_cells_b.count(sig_data))
 		{
-			bool enable_invert = mux_cells_a.count(sig_data) != 0;
-			Cell *mux = enable_invert ? mux_cells_a.at(sig_data) : mux_cells_b.at(sig_data);
-			SigSpec check_q = sigmap(mux->getPort(enable_invert ? "\\B" : "\\A"));
+			RTLIL::SigSpec en;
+			RTLIL::SigSpec check_q;
+
+			do {
+				bool enable_invert = mux_cells_a.count(sig_data) != 0;
+				Cell *mux = enable_invert ? mux_cells_a.at(sig_data) : mux_cells_b.at(sig_data);
+				check_q = sigmap(mux->getPort(enable_invert ? "\\B" : "\\A"));
+				sig_data = sigmap(mux->getPort("\\Y"));
+				en.append(enable_invert ? module->LogicNot(NEW_ID, mux->getPort("\\S")) : mux->getPort("\\S"));
+			} while (mux_cells_a.count(sig_data) || mux_cells_b.count(sig_data));
 
-			sig_data = sigmap(mux->getPort("\\Y"));
 			for (auto bit : sig_data)
 				if (sigbit_users_count[bit] > 1)
 					goto skip_ff_after_read_merging;
@@ -195,7 +201,7 @@ struct MemoryDffWorker
 			{
 				disconnect_dff(sig_data);
 				cell->setPort("\\CLK", clk_data);
-				cell->setPort("\\EN", enable_invert ? module->LogicNot(NEW_ID, mux->getPort("\\S")) : mux->getPort("\\S"));
+				cell->setPort("\\EN", en.size() > 1 ? module->ReduceAnd(NEW_ID, en) : en);
 				cell->setPort("\\DATA", sig_data);
 				cell->parameters["\\CLK_ENABLE"] = RTLIL::Const(1);
 				cell->parameters["\\CLK_POLARITY"] = RTLIL::Const(clk_polarity);
diff --git a/tests/memories/issue00710.v b/tests/memories/issue00710.v
new file mode 100644
index 000000000..7a5fad1c2
--- /dev/null
+++ b/tests/memories/issue00710.v
@@ -0,0 +1,17 @@
+// expect-wr-ports 1
+// expect-rd-ports 1
+// expect-rd-clk \clk
+
+module top(input clk, input we, re, reset, input [7:0] addr, wdata, output reg [7:0] rdata);
+
+reg [7:0] bram[0:255];
+(* keep *) reg dummy;
+
+always @(posedge clk)
+	if (reset)
+		dummy <= 1'b0;
+	else if (re)
+		rdata <= bram[addr];
+	else if (we)
+		bram[addr] <= wdata;
+endmodule
diff --git a/tests/memories/run-test.sh b/tests/memories/run-test.sh
index 734a96682..d0537bb98 100755
--- a/tests/memories/run-test.sh
+++ b/tests/memories/run-test.sh
@@ -14,7 +14,7 @@ shift "$((OPTIND-1))"
 
 bash ../tools/autotest.sh $seed -G *.v
 
-for f in `egrep -l 'expect-(wr|rd)-ports' *.v`; do
+for f in `egrep -l 'expect-(wr-ports|rd-ports|rd-clk)' *.v`; do
 	echo -n "Testing expectations for $f .."
 	../../yosys -qp "proc; opt; memory -nomap;; dump -outfile ${f%.v}.dmp t:\$mem" $f
 	if grep -q expect-wr-ports $f; then
@@ -25,6 +25,10 @@ for f in `egrep -l 'expect-(wr|rd)-ports' *.v`; do
 		grep -q "parameter \\\\RD_PORTS $(gawk '/expect-rd-ports/ { print $3; }' $f)\$" ${f%.v}.dmp ||
 				{ echo " ERROR: Unexpected number of read ports."; false; }
 	fi
+	if grep -q expect-rd-clk $f; then
+		grep -q "connect \\\\RD_CLK \\$(gawk '/expect-rd-clk/ { print $3; }' $f)\$" ${f%.v}.dmp ||
+				{ echo " ERROR: Unexpected read clock."; false; }
+	fi
 	echo " ok."
 done