[PATCH] math: fix Wshift-overflow warning.

[H.J. Lu]

On Mon, Sep 22, 2025 at 1:29 PM Collin Funk <collin.funk1@gmail.com> wrote:
>
> When compiling on x86_64 with -Wshift-overflow=2 you can see the
> following warning:
>
> ../sysdeps/ieee754/flt-32/math_config.h: In function ‘is_inf’:
> ../sysdeps/ieee754/flt-32/math_config.h:184:37: warning: result of ‘2139095040 << 1’ requires 33 bits to represent, but ‘int’ only has 32 bits [-Wshift-overflow=]
>   184 |   return (x << 1) == (EXPONENT_MASK << 1);
>       |                                     ^~
>
> This patch adjusts the definitions to use UINT32_C. This matches the
> definitions in sysdeps/ieee754/dbl-64/math_config.h which use UINT64_C
> for these definitions.
> ---
>  sysdeps/ieee754/flt-32/math_config.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/sysdeps/ieee754/flt-32/math_config.h b/sysdeps/ieee754/flt-32/math_config.h
> index 33ea631d5f..6bb5c3324c 100644
> --- a/sysdeps/ieee754/flt-32/math_config.h
> +++ b/sysdeps/ieee754/flt-32/math_config.h
> @@ -166,11 +166,11 @@ issignalingf_inline (float x)
>  #define MANTISSA_WIDTH  23
>  #define EXPONENT_WIDTH  8
>  #define EXPONENT_BIAS   127
> -#define MANTISSA_MASK   0x007fffff
> -#define EXPONENT_MASK   0x7f800000
> -#define EXP_MANT_MASK   0x7fffffff
> -#define QUIET_NAN_MASK  0x00400000
> -#define SIGN_MASK       0x80000000
> +#define MANTISSA_MASK   UINT32_C (0x007fffff)
> +#define EXPONENT_MASK   UINT32_C (0x7f800000)
> +#define EXP_MANT_MASK   UINT32_C (0x7fffffff)
> +#define QUIET_NAN_MASK  UINT32_C (0x00400000)
> +#define SIGN_MASK       UINT32_C (0x80000000)
>
>  static inline bool
>  is_nan (uint32_t x)
> --
> 2.51.0
>

LGTM.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

-- 
H.J.