Add regression test for issue #1286.

ivtest/ivltests/br_gh1286.v

@@ -0,0 +1,38 @@
+module test;
+
+reg [1:0] a;
+reg       b;
+reg       c;
+reg       d;
+
+always_latch begin
+  if (a[1])
+    c = 1;
+  else if (a[0])
+    c = 0;
+end
+
+always_latch begin
+  if (b)
+    d = 1;
+  else if (a[0])
+    d = 0;
+end
+
+reg failed = 0;
+
+initial begin
+  $monitor("%0t : %b %b : %b %b", $time, a, b, c, d);
+  a[0] = 1'b1;
+  #1 if (c !== 1'b0 && d !== 1'b0) failed = 1;
+  a[1] = 1'b1;
+  #1 if (c !== 1'b1 && d !== 1'b0) failed = 1;
+  b = 1'b1;
+  #1 if (c !== 1'b1 && d !== 1'b1) failed = 1;
+  if (failed)
+    $display("FAILED");
+  else
+    $display("PASSED");
+end
+
+endmodule

ivtest/regress-vvp.list

@@ -69,6 +69,7 @@ br_gh1256a			vvp_tests/br_gh1256a.json
 br_gh1256b			vvp_tests/br_gh1256b.json
 br_gh1258a			vvp_tests/br_gh1258a.json
 br_gh1258b			vvp_tests/br_gh1258b.json
+br_gh1286			vvp_tests/br_gh1286.json
 ca_time_real			vvp_tests/ca_time_real.json
 case1				vvp_tests/case1.json
 case2				vvp_tests/case2.json

ivtest/vvp_tests/br_gh1286.json

@@ -0,0 +1,5 @@
+{
+    "type" : "normal",
+    "source" : "br_gh1286.v",
+    "iverilog-args" : [ "-g2009" ]
+}