coccinelle: misc: add excluded_middle.cocci script

Check for !A || A && B condition. It's equivalent to !A || B.
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

scripts/coccinelle/misc/excluded_middle.cocci

+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Condition !A || A && B is equivalent to !A || B.
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+
+virtual patch
+virtual context
+virtual org
+virtual report
+
+@r depends on !patch@
+expression A, B;
+position p;
+@@
+
+* !A || (A &&@p B)
+
+@depends on patch@
+expression A, B;
+@@
+
+  !A ||
+-       (A && B)
++       B
+
+@script:python depends on report@
+p << r.p;
+@@
+
+coccilib.report.print_report(p[0], "WARNING !A || A && B is equivalent to !A || B")
+
+@script:python depends on org@
+p << r.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING !A || A && B is equivalent to !A || B")