[cocci] [PATCH 3/3] coccinelle: misc: minmax: improve performance when no candidate exists

[Sang-Heon Jeon <ekffu200098@gmail.com>]

The rules that report an opencoded min() or max() search every
function body, even when the file contains nothing to find.

To avoid this, collect the candidates first and run the search only
when one exists. A candidate is any conditional expression whose
condition is a comparison.

Every opencoded min() or max() is also a candidate, so the same
opportunities are reported as before and the output does not
change. A report-mode run over every .c file in the tree produces
identical output.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 scripts/coccinelle/misc/minmax.cocci | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/scripts/coccinelle/misc/minmax.cocci b/scripts/coccinelle/misc/minmax.cocci
index ca4830ae3042..93c074b9439f 100644
--- a/scripts/coccinelle/misc/minmax.cocci
+++ b/scripts/coccinelle/misc/minmax.cocci
@@ -17,7 +17,21 @@ virtual org
 virtual context
 virtual patch
 
-@rmax depends on !patch@
+@max_candidate@
+expression E1, E2, E3, E4;
+binary operator cmp = {>, >=};
+@@
+
+	(E1 cmp E2 ? E3 : E4)
+
+@min_candidate@
+expression E1, E2, E3, E4;
+binary operator cmp = {<, <=};
+@@
+
+	(E1 cmp E2 ? E3 : E4)
+
+@rmax depends on !patch && max_candidate@
 identifier func;
 expression x, y;
 binary operator cmp = {>, >=};
@@ -51,7 +65,7 @@ func(...)
 }
 
 // Ignore errcode returns.
-@errcode@
+@errcode depends on min_candidate@
 position p;
 identifier func;
 expression x;
@@ -65,7 +79,7 @@ func(...)
 	...>
 }
 
-@rmin depends on !patch@
+@rmin depends on !patch && min_candidate@
 identifier func;
 expression x, y;
 binary operator cmp = {<, <=};
@@ -98,7 +112,7 @@ func(...)
 	...>
 }
 
-@pmax depends on patch@
+@pmax depends on patch && max_candidate@
 identifier func;
 expression x, y;
 binary operator cmp = {>=, >};
@@ -131,7 +145,7 @@ func(...)
 	...>
 }
 
-@pmin depends on patch@
+@pmin depends on patch && min_candidate@
 identifier func;
 expression x, y;
 binary operator cmp = {<=, <};
-- 
2.43.0