[PATCH v2] coccinelle: misc: add excluded_middle.cocci script

[Denis Efremov]

Check for !A || A && B condition. It's equivalent to !A || B.

Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
Changes in v2:
 - spelling mistake fixed
 - position variable moved on the && operator
 - patch pattern changed to - (A && B)
 - word "condition" removed from warning message

 scripts/coccinelle/misc/excluded_middle.cocci | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 scripts/coccinelle/misc/excluded_middle.cocci

diff --git a/scripts/coccinelle/misc/excluded_middle.cocci b/scripts/coccinelle/misc/excluded_middle.cocci
new file mode 100644
index 000000000000..ab28393e4843
--- /dev/null
+++ b/scripts/coccinelle/misc/excluded_middle.cocci
@@ -0,0 +1,39 @@
+// 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")
-- 
2.26.2