"unlikely" fails to compile with --with-debug on Ununtu

[Mark Atwood]

Trying to build from bzr revno: 608 on ubuntu jaunty on EC2 (ami-0d729464). Uses gcc version 4.3.3

When doing ./configure --with-debug && make

lots of compile failures regarding "unlikely()"

as an example:

memcached_fetch.c: In function ‘memcached_fetch’:
memcached_fetch.c:11: error: conversion to ‘long int’ from ‘uint32_t’ may change the sign of the result [-Wsign-conversion]
memcached_fetch.c: In function ‘memcached_fetch_result’:
memcached_fetch.c:48: error: conversion to ‘long int’ from ‘uint32_t’ may change the sign of the result [-Wsign-conversion]

[Monty Taylor (mordred)]

Mark Atwood wrote:
> Public bug reported:
>
> Trying to build from bzr revno: 608 on ubuntu jaunty on EC2 (ami-
> 0d729464). Uses gcc version 4.3.3
>
> When doing ./configure --with-debug && make
>
> lots of compile failures regarding "unlikely()"
>
> as an example:
>
> memcached_fetch.c: In function ‘memcached_fetch’:
> memcached_fetch.c:11: error: conversion to ‘long int’ from ‘uint32_t’ may change the sign of the result [-Wsign-conversion]
> memcached_fetch.c: In function ‘memcached_fetch_result’:
> memcached_fetch.c:48: error: conversion to ‘long int’ from ‘uint32_t’ may change the sign of the result [-Wsign-conversion]

This is actually not related to unlikey() at all. This is releated to
the AND operator (&) being applied to a uint32_t and an enum.

One can work around this by doing a cast to uint32_t on the enum value.

[Trond Norbye (trond-norbye)]

If it isn't related to unlikely() at all... why do it go away if you replace unlikely() with if() ?