linux/scripts/coccinelle/misc/orplus.cocci
Julia Lawall 937c812dfc coccinelle: orplus: reorganize to improve performance
Adding two #define constants is less common than performing & and |
operations on them, so put the addition first to reduce the set of cases
that have to be considered in detail.  At the same time, add & and |
patterns for both arguments of +, to account for commutativity and obtain
more results.

Running time is divided by 3 when applying this to the whole kernel on my
laptop with an Intel i5-6200U CPU.

Signed-off-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-11-16 08:56:42 +09:00

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/// Check for constants that are added but are used elsewhere as bitmasks
/// The results should be checked manually to ensure that the nonzero
/// bits in the two constants are actually disjoint.
///
// Confidence: Moderate
// Copyright: (C) 2013 Julia Lawall, INRIA/LIP6. GPLv2.
// Copyright: (C) 2013 Gilles Muller, INRIA/LIP6. GPLv2.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: --no-includes --include-headers
virtual org
virtual report
virtual context
@r@
constant c,c1;
identifier i,i1;
position p;
@@
(
c1 + c - 1
|
c1@i1 +@p c@i
)
@s@
constant r.c, r.c1;
identifier i;
expression e;
@@
(
e | c@i
|
e & c@i
|
e |= c@i
|
e &= c@i
|
e | c1@i
|
e & c1@i
|
e |= c1@i
|
e &= c1@i
)
@depends on s@
position r.p;
constant c1,c2;
@@
* c1 +@p c2
@script:python depends on s && org@
p << r.p;
@@
cocci.print_main("sum of probable bitmasks, consider |",p)
@script:python depends on s && report@
p << r.p;
@@
msg = "WARNING: sum of probable bitmasks, consider |"
coccilib.report.print_report(p[0],msg)