The function like macro __is_nonneg() casts its argument to (long long)
in an attempt to silence -Wtype-limits warnings on unsigned values.
But this workaround is incomplete as proven here:
$ cat foo.c
#include <linux/minmax.h>
int foo(unsigned int a)
{
return __is_nonneg(a);
}
$ make CFLAGS_KERNEL="-Wtype-limits" foo.o
CALL scripts/checksyscalls.sh
DESCEND objtool
INSTALL libsubcmd_headers
CC foo.o
foo.c: In function 'foo':
./include/linux/minmax.h:68:57: warning: comparison is always true due to limited range of data type [-Wtype-limits]
68 | #define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
| ^~
./include/linux/compiler.h:350:50: note: in definition of macro 'statically_true'
350 | #define statically_true(x) (__builtin_constant_p(x) && (x))
| ^
foo.c:5:16: note: in expansion of macro '__is_nonneg'
5 | return __is_nonneg(a);
| ^~~~~~~~~~~
./include/linux/minmax.h:68:57: warning: comparison is always true due to limited range of data type [-Wtype-limits]
68 | #define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
| ^~
./include/linux/compiler.h:350:57: note: in definition of macro 'statically_true'
350 | #define statically_true(x) (__builtin_constant_p(x) && (x))
| ^
foo.c:5:16: note: in expansion of macro '__is_nonneg'
5 | return __is_nonneg(a);
| ^~~~~~~~~~~
And because -Wtype-limits is now globally disabled, such a workaround
now becomes useless. Remove the __is_nonneg()'s cast and its related
comment.
Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
Changelog:
v1 -> v2: new patch
---
include/linux/minmax.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index a0158db54a04..3e2e3e539ba1 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -52,9 +52,6 @@
/*
* Check whether a signed value is always non-negative.
*
- * A cast is needed to avoid any warnings from values that aren't signed
- * integer types (in which case the result doesn't matter).
- *
* On 64-bit any integer or pointer type can safely be cast to 'long long'.
* But on 32-bit we need to avoid warnings about casting pointers to integers
* of different sizes without truncating 64-bit values so 'long' or 'long long'
@@ -65,7 +62,7 @@
* but they are handled by the !is_signed_type() case).
*/
#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__
-#define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
+#define __is_nonneg(ux) statically_true((ux) >= 0)
#else
#define __is_nonneg(ux) statically_true( \
(typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0)
--
2.51.2On Fri, 19 Dec 2025 23:39:48 +0100
Vincent Mailhol <mailhol@kernel.org> wrote:
> The function like macro __is_nonneg() casts its argument to (long long)
> in an attempt to silence -Wtype-limits warnings on unsigned values.
nak.
The cast is needed for pointer types, not for -Wtype-limits.
which is why the '#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__'
test is there.
David
>
> But this workaround is incomplete as proven here:
>
> $ cat foo.c
> #include <linux/minmax.h>
>
> int foo(unsigned int a)
> {
> return __is_nonneg(a);
> }
> $ make CFLAGS_KERNEL="-Wtype-limits" foo.o
> CALL scripts/checksyscalls.sh
> DESCEND objtool
> INSTALL libsubcmd_headers
> CC foo.o
> foo.c: In function 'foo':
> ./include/linux/minmax.h:68:57: warning: comparison is always true due to limited range of data type [-Wtype-limits]
> 68 | #define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
> | ^~
> ./include/linux/compiler.h:350:50: note: in definition of macro 'statically_true'
> 350 | #define statically_true(x) (__builtin_constant_p(x) && (x))
> | ^
> foo.c:5:16: note: in expansion of macro '__is_nonneg'
> 5 | return __is_nonneg(a);
> | ^~~~~~~~~~~
> ./include/linux/minmax.h:68:57: warning: comparison is always true due to limited range of data type [-Wtype-limits]
> 68 | #define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
> | ^~
> ./include/linux/compiler.h:350:57: note: in definition of macro 'statically_true'
> 350 | #define statically_true(x) (__builtin_constant_p(x) && (x))
> | ^
> foo.c:5:16: note: in expansion of macro '__is_nonneg'
> 5 | return __is_nonneg(a);
> | ^~~~~~~~~~~
>
> And because -Wtype-limits is now globally disabled, such a workaround
> now becomes useless. Remove the __is_nonneg()'s cast and its related
> comment.
>
> Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
> ---
> Changelog:
>
> v1 -> v2: new patch
> ---
> include/linux/minmax.h | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/include/linux/minmax.h b/include/linux/minmax.h
> index a0158db54a04..3e2e3e539ba1 100644
> --- a/include/linux/minmax.h
> +++ b/include/linux/minmax.h
> @@ -52,9 +52,6 @@
> /*
> * Check whether a signed value is always non-negative.
> *
> - * A cast is needed to avoid any warnings from values that aren't signed
> - * integer types (in which case the result doesn't matter).
> - *
> * On 64-bit any integer or pointer type can safely be cast to 'long long'.
> * But on 32-bit we need to avoid warnings about casting pointers to integers
> * of different sizes without truncating 64-bit values so 'long' or 'long long'
> @@ -65,7 +62,7 @@
> * but they are handled by the !is_signed_type() case).
> */
> #if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__
> -#define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
> +#define __is_nonneg(ux) statically_true((ux) >= 0)
> #else
> #define __is_nonneg(ux) statically_true( \
> (typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0)
>
On 20/12/2025 at 11:02, David Laight wrote: > On Fri, 19 Dec 2025 23:39:48 +0100 > Vincent Mailhol <mailhol@kernel.org> wrote: > >> The function like macro __is_nonneg() casts its argument to (long long) >> in an attempt to silence -Wtype-limits warnings on unsigned values. > > nak. > > The cast is needed for pointer types, not for -Wtype-limits. > which is why the '#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__' > test is there. OK. I will remove that fourth patch in v3. Yours sincerely, Vincent Mailhol
Hi Vincent,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 3e7f562e20ee87a25e104ef4fce557d39d62fa85]
url: https://github.com/intel-lab-lkp/linux/commits/Vincent-Mailhol/kbuild-remove-gcc-s-Wtype-limits/20251220-064204
base: 3e7f562e20ee87a25e104ef4fce557d39d62fa85
patch link: https://lore.kernel.org/r/20251219-remove_wtype-limits-v2-4-2e92b3f566c5%40kernel.org
patch subject: [PATCH v2 4/4] minmax: remove useless cast in __is_nonneg()
config: x86_64-rhel-9.4-ltp (https://download.01.org/0day-ci/archive/20251220/202512201303.je0bERQn-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251220/202512201303.je0bERQn-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512201303.je0bERQn-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from <command-line>:
lib/lzo/lzo1x_compress.c: In function 'lzo1x_1_do_compress':
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:10: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:10: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:27: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:27: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
--
In file included from <command-line>:
lib/lzo/lzo1x_compress.c: In function 'lzo1x_1_do_compress_safe':
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:10: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:10: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:27: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
>> include/linux/minmax.h:65:46: warning: ordered comparison of pointer with integer zero [-Wextra]
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~
include/linux/compiler_types.h:610:23: note: in definition of macro '__compiletime_assert'
610 | if (!(condition)) \
| ^~~~~~~~~
include/linux/compiler_types.h:630:9: note: in expansion of macro '_compiletime_assert'
630 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:90:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~~~~~~~
include/linux/minmax.h:65:25: note: in expansion of macro 'statically_true'
65 | #define __is_nonneg(ux) statically_true((ux) >= 0)
| ^~~~~~~~~~~~~~~
include/linux/minmax.h:50:14: note: in expansion of macro '__is_nonneg'
50 | (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
| ^~~~~~~~~~~
include/linux/minmax.h:72:27: note: in expansion of macro '__sign_use'
72 | (__sign_use(ux) & __sign_use(uy))
| ^~~~~~~~~~
include/linux/minmax.h:90:27: note: in expansion of macro '__types_ok'
90 | BUILD_BUG_ON_MSG(!__types_ok(ux, uy), \
| ^~~~~~~~~~
include/linux/minmax.h:95:9: note: in expansion of macro '__careful_cmp_once'
95 | __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
| ^~~~~~~~~~~~~~~~~~
include/linux/minmax.h:102:25: note: in expansion of macro '__careful_cmp'
102 | #define min(x, y) __careful_cmp(min, x, y)
| ^~~~~~~~~~~~~
lib/lzo/lzo1x_compress.c:65:54: note: in expansion of macro 'min'
65 | const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
| ^~~
vim +65 include/linux/minmax.h
9
10 /*
11 * min()/max()/clamp() macros must accomplish several things:
12 *
13 * - Avoid multiple evaluations of the arguments (so side-effects like
14 * "x++" happen only once) when non-constant.
15 * - Perform signed v unsigned type-checking (to generate compile
16 * errors instead of nasty runtime surprises).
17 * - Unsigned char/short are always promoted to signed int and can be
18 * compared against signed or unsigned arguments.
19 * - Unsigned arguments can be compared against non-negative signed constants.
20 * - Comparison of a signed argument against an unsigned constant fails
21 * even if the constant is below __INT_MAX__ and could be cast to int.
22 */
23 #define __typecheck(x, y) \
24 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
25
26 /*
27 * __sign_use for integer expressions:
28 * bit #0 set if ok for unsigned comparisons
29 * bit #1 set if ok for signed comparisons
30 *
31 * In particular, statically non-negative signed integer expressions
32 * are ok for both.
33 *
34 * NOTE! Unsigned types smaller than 'int' are implicitly converted to 'int'
35 * in expressions, and are accepted for signed conversions for now.
36 * This is debatable.
37 *
38 * Note that 'x' is the original expression, and 'ux' is the unique variable
39 * that contains the value.
40 *
41 * We use 'ux' for pure type checking, and 'x' for when we need to look at the
42 * value (but without evaluating it for side effects!
43 * Careful to only ever evaluate it with sizeof() or __builtin_constant_p() etc).
44 *
45 * Pointers end up being checked by the normal C type rules at the actual
46 * comparison, and these expressions only need to be careful to not cause
47 * warnings for pointer use.
48 */
49 #define __sign_use(ux) (is_signed_type(typeof(ux)) ? \
50 (2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
51
52 /*
53 * Check whether a signed value is always non-negative.
54 *
55 * On 64-bit any integer or pointer type can safely be cast to 'long long'.
56 * But on 32-bit we need to avoid warnings about casting pointers to integers
57 * of different sizes without truncating 64-bit values so 'long' or 'long long'
58 * must be used depending on the size of the value.
59 *
60 * This does not work for 128-bit signed integers since the cast would truncate
61 * them, but we do not use s128 types in the kernel (we do use 'u128',
62 * but they are handled by the !is_signed_type() case).
63 */
64 #if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__
> 65 #define __is_nonneg(ux) statically_true((ux) >= 0)
66 #else
67 #define __is_nonneg(ux) statically_true( \
68 (typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0)
69 #endif
70
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