Messages in this thread Patch in this message | | | From | Justin Stitt <> | Subject | [PATCH v2] include/uapi/linux/swab.h: move explicit cast outside ternary | Date | Tue, 7 Jun 2022 17:14:22 -0700 |
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A cast inside __builtin_constant_p doesn't do anything since it should evaluate as constant at compile time irrespective of this cast. Instead, I moved this cast outside the ternary to ensure the return type is as expected.
For instance, if __HAVE_BUILTIN_BSWAP16__ was not defined then __swab16 is actually returning an `int` not a `u16` due to integer promotion as described by Nick in this thread. This has repercussions when building with clang -Wformat. This fix should solve many of these warnings.
Link: https://github.com/ClangBuiltLinux/linux/issues/378 Suggested-by: Nathan Chancellor <nathan@kernel.org> Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Justin Stitt <jstitt007@gmail.com> --- include/uapi/linux/swab.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/uapi/linux/swab.h b/include/uapi/linux/swab.h index f6be3f2e6fee..ab5a1283800c 100644 --- a/include/uapi/linux/swab.h +++ b/include/uapi/linux/swab.h @@ -99,10 +99,10 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) * @x: value to byteswap */ #ifdef __HAVE_BUILTIN_BSWAP16__ -#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) +#define __swab16(x) (__u16)__builtin_bswap16(x) #else #define __swab16(x) \ - (__u16)(__builtin_constant_p((__u16)(x)) ? \ + (__u16)(__builtin_constant_p(x) ? \ ___constant_swab16(x) : \ __fswab16(x)) #endif @@ -112,10 +112,10 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) * @x: value to byteswap */ #ifdef __HAVE_BUILTIN_BSWAP32__ -#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) +#define __swab32(x) (__u32)__builtin_bswap32(x) #else #define __swab32(x) \ - (__builtin_constant_p((__u32)(x)) ? \ + (__u32)(__builtin_constant_p(x) ? \ ___constant_swab32(x) : \ __fswab32(x)) #endif @@ -125,10 +125,10 @@ static inline __attribute_const__ __u32 __fswahb32(__u32 val) * @x: value to byteswap */ #ifdef __HAVE_BUILTIN_BSWAP64__ -#define __swab64(x) (__u64)__builtin_bswap64((__u64)(x)) +#define __swab64(x) (__u64)__builtin_bswap64(x) #else #define __swab64(x) \ - (__builtin_constant_p((__u64)(x)) ? \ + (__u64)(__builtin_constant_p(x) ? \ ___constant_swab64(x) : \ __fswab64(x)) #endif -- 2.30.2
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