Re: [PATCH v3 1/2] migration: Fix incorrect integer->float conversion caught by clang

[Richard Henderson]

On 11/22/19 9:00 AM, Markus Armbruster wrote:
> From: Fangrui Song <address@hidden>
> 
> Clang does not like qmp_migrate_set_downtime()'s code to clamp double
> @value to 0..INT64_MAX:
> 
>     qemu/migration/migration.c:2038:24: error: implicit conversion from 
> 'long' to 'double' changes value from 9223372036854775807 to 
> 9223372036854775808 [-Werror,-Wimplicit-int-float-conversion]
> 
> The warning will be enabled by default in clang 10. It is not
> available for clang <= 9.
> 
> The clamp is actually useless; @value is checked to be within
> 0..MAX_MIGRATE_DOWNTIME_SECONDS immediately before.  Delete it.
> 
> While there, make the conversion from double to int64_t explicit.
> 
> Signed-off-by: Fangrui Song <address@hidden>
> Reviewed-by: Markus Armbruster <address@hidden>
> [Patch split, commit message improved]
> Signed-off-by: Markus Armbruster <address@hidden>
> ---
>  migration/migration.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Reviewed-by: Richard Henderson <address@hidden>


r~