Add regression test for out-of-bounds array assignment operator

Check that an assignment operator on an out-of-bounds array element works
as expected. The out-of-bounds access should leave the array unmodified,
but the right-hand side must be evaluated regardless.

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

ivtest/ivltests/assign_op_oob.v

@@ -0,0 +1,44 @@
+// Check that the assignment operator is supported for out-of-bounds indices.
+// The write should be skipped, but side effects of the right-hand side
+// expression should still get evaluated.
+
+module test;
+
+  // Check that wider than 32 works
+  logic [39:0] a[1:0];
+  integer i;
+  logic [39:0] j = 0;
+
+  function logic [39:0] f;
+    j++;
+    return j;
+  endfunction
+
+  initial begin
+    a[0] = 23;
+    a[1] = 42;
+
+    // Immediate out-of-bounds indices
+    a[-1] += f();
+    a[2] += f();
+    a['hx] += f();
+
+    // Variable out-of-bounds indices
+    i = -1;
+    a[i] += f();
+    i = 2;
+    a[i] += f();
+    i = 'hx;
+    a[i] += f();
+
+    // Check that the in-bounds elements do not get affected by out-of-bounds
+    // updates. Check that the left-hand side of the operator assignment gets
+    // evaluated.
+    if (a[0] == 23 && a[1] == 42 && j == 6) begin
+      $display("PASSED");
+    end else begin
+      $display("FAILED");
+    end
+  end
+
+endmodule

ivtest/regress-sv.list

@@ -99,6 +99,7 @@ array_packed		normal,-g2005-sv	ivltests
 assign_op_after_cmp1	normal,-g2009		ivltests
 assign_op_after_cmp2	normal,-g2009		ivltests
 assign_op_concat	normal,-g2009		ivltests
+assign_op_oob		normal,-g2009		ivltests
 assign_op_type		normal,-g2009		ivltests
 bitp1			normal,-g2005-sv	ivltests
 bits			normal,-g2005-sv	ivltests

ivtest/regress-vlog95.list

@@ -792,6 +792,7 @@ writemem-invalid	RE			ivltests gold=writemem-invalid-vlog95.gold
 
 # For Verilog 95 signed is supported as an option (-pallowsigned=1).
 array6			normal,-pallowsigned=1	ivltests
+assign_op_oob		normal,-g2009,-pallowsigned=1	ivltests
 assign_op_type		normal,-g2009,-pallowsigned=1	ivltests
 bitp1			normal,-g2009,-pallowsigned=1	ivltests
 bits			normal,-g2009,-pallowsigned=1	ivltests