Add regression test for invalid array query signedness

Check arithmetic right shifts of invalid `$left`, `$right`, `$low`,
`$high`, `$increment` and `$size` results. Cover dimensions below and above
the valid range and include valid signed results as controls.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

Author: larsclausen

ivtest/ivltests/array_query_invalid_signedness.v

@@ -0,0 +1,41 @@
+// Check that invalid array-query results keep their signed integer type.
+
+module test;
+
+  reg [7:0] values [0:1];
+  reg failed;
+
+  `define check(val, exp) \
+    if (val !== exp) begin \
+      $display("FAILED(%0d): '%s' expected %b, got %b", `__LINE__, \
+               `"val`", exp, val); \
+      failed = 1'b1; \
+    end
+
+  initial begin
+    failed = 1'b0;
+
+    // Dimension 0 does not exist.
+    `check($left(values, 0) >>> 8, 32'bx);
+    `check($right(values, 0) >>> 8, 32'bx);
+    `check($low(values, 0) >>> 8, 32'bx);
+    `check($high(values, 0) >>> 8, 32'bx);
+    `check($increment(values, 0) >>> 8, 32'bx);
+    `check($size(values, 0) >>> 8, 32'bx);
+
+    // Dimension 3 does not exist.
+    `check($left(values, 3) >>> 8, 32'bx);
+    `check($right(values, 3) >>> 8, 32'bx);
+    `check($low(values, 3) >>> 8, 32'bx);
+    `check($high(values, 3) >>> 8, 32'bx);
+    `check($increment(values, 3) >>> 8, 32'bx);
+    `check($size(values, 3) >>> 8, 32'bx);
+
+    `check($increment(values, 1) >>> 8, -1);
+    `check($increment(values, 2) >>> 8, 0);
+    if (!failed) begin
+      $display("PASSED");
+    end
+  end
+
+endmodule

ivtest/regress-vvp.list

@@ -10,6 +10,7 @@ array_index_real_fail		vvp_tests/array_index_real_fail.json
 array_packed_sysfunct		vvp_tests/array_packed_sysfunct.json
 array_packed_value_list		vvp_tests/array_packed_value_list.json
 array_packed_write_read		vvp_tests/array_packed_write_read.json
+array_query_invalid_signedness	vvp_tests/array_query_invalid_signedness.json
 array_slice_concat		vvp_tests/array_slice_concat.json
 assign_op_return_select		vvp_tests/assign_op_return_select.json
 assign_op_signed1		vvp_tests/assign_op_signed1.json

ivtest/vvp_tests/array_query_invalid_signedness.json

@@ -0,0 +1,5 @@
+{
+    "type"          : "normal",
+    "source"        : "array_query_invalid_signedness.v",
+    "iverilog-args" : [ "-g2005-sv" ]
+}