Adding support for the SVA implication operator. For partial fix of issue #1292.

test_regress/t/t_assert_implication.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003-2009 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+scenarios(simulator => 1);
+
+compile(
+    verilator_flags2 => ['--assert --cc'],
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_assert_implication.v

@@ -0,0 +1,57 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Peter Monsson.
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk
+   );
+
+   input clk;
+   integer cyc; initial cyc=1;
+
+   Test test (/*AUTOINST*/
+	      // Inputs
+	      .clk			(clk));
+
+   always @ (posedge clk) begin
+      if (cyc!=0) begin
+         cyc <= cyc + 1;
+         if (cyc==10) begin
+            $write("*-* All Finished *-*\n");
+            $finish;
+         end
+      end
+   end
+
+endmodule
+
+module Test
+  (
+   input clk
+   );
+
+`ifdef FAIL_ASSERT_1
+   assert property (
+     @(posedge clk)
+     1 |-> 0
+   ) else $display("wrong implication");
+`endif
+
+   assert property (
+     @(posedge clk)
+     1 |-> 1
+   );
+
+   assert property (
+     @(posedge clk)
+     0 |-> 0
+   );
+
+   assert property (
+     @(posedge clk)
+     0 |-> 1
+   );
+   
+endmodule

test_regress/t/t_assert_implication_bad.pl

@@ -0,0 +1,26 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003-2009 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+scenarios(simulator => 1);
+
+top_filename("t/t_assert_implication.v");
+
+compile(
+    v_flags2 => ['+define+FAIL_ASSERT_1'],
+    verilator_flags2 => ['--assert --cc'],
+    );
+
+execute(
+    );
+
+# We expect to get a message when this assert fires:
+file_grep($Self->{run_log_filename}, qr/wrong implication/);
+
+ok(1);
+1;