Add regression tests for invalid size casts

Check that an error is reported for size casts with either a value of 0, a
negative value or an undefined value.

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

ivtest/ivltests/size_cast_fail1.v

@@ -0,0 +1,12 @@
+// Check that an error is reported when using a zero value for a size cast.
+
+module test;
+
+  localparam integer N = 0;
+
+  initial begin
+    int x, y;
+    y = N'(x); // This should fail, N is zero
+  end
+
+endmodule

ivtest/ivltests/size_cast_fail2.v

@@ -0,0 +1,12 @@
+// Check that an error is reported when using a negative value for a size cast.
+
+module test;
+
+  localparam integer N = -1;
+
+  initial begin
+    int x, y;
+    y = N'(x); // This should fail, N is negative
+  end
+
+endmodule

ivtest/ivltests/size_cast_fail3.v

@@ -0,0 +1,12 @@
+// Check that an error is reported when using an undefined value for a size cast.
+
+module test;
+
+  localparam integer N = 32'hx;
+
+  initial begin
+    int x, y;
+    y = N'(x); // This should fail, N is undefined
+  end
+
+endmodule

ivtest/regress-sv.list

@@ -465,6 +465,9 @@ size_cast2		normal,-g2005-sv	ivltests
 size_cast3		normal,-g2009		ivltests
 size_cast4		normal,-g2009		ivltests
 size_cast5		normal,-g2009		ivltests
+size_cast_fail1		CE,-g2009		ivltests
+size_cast_fail2		CE,-g2009		ivltests
+size_cast_fail3		CE,-g2009		ivltests
 slongint_test		normal,-g2005-sv	ivltests
 sshortint_test		normal,-g2005-sv	ivltests
 string_events		normal,-g2009		ivltests gold=string_events.gold