Re: [Patch, MIPS] Fix warning from malloc/malloc.c

["Carlos O'Donell" <carlos at redhat dot com>]

On 12/10/2014 06:13 PM, Steve Ellcey  wrote:
> Here is a fix for another warning (now error) found in my MIPS build.
> 
> 	malloc.c: In function '__posix_memalign':
> 	malloc.c:4976:50: error: logical not is only applied to the left hand side of comparison [-Werror=logical-not-parentheses]
> 		|| !powerof2 (alignment / sizeof (void *)) != 0
>                                                   ^
> 	cc1: all warnings being treated as errors
> 
> 
> The fix is to remove the '!= 0' comparision since it is redundant.

Removing '!= 0' creates a boolean coersion from the int type and we avoid
this in glibc because it is clearer to say exactly what you mean e.g. != 0 or == 0.

Is not the right fix to add a bracket to clarify the `!` is applied to the left
side only e.g. "|| (!powerof2 (alignment / sizeof (void *))) != 0"?
 
> OK to checkin?
> 
> Steve Ellcey
> sellcey@imgtec.com
> 
> 2014-12-10  Steve Ellcey  <sellcey@imgtec.com>
> 
> 	* malloc/malloc.c: Fix powerof2 check.
> 
> 
> diff --git a/malloc/malloc.c b/malloc/malloc.c
> index 6bfb859..cb91b97 100644
> --- a/malloc/malloc.c
> +++ b/malloc/malloc.c
> @@ -4973,7 +4973,7 @@ __posix_memalign (void **memptr, size_t alignment, size_t size)
>    /* Test whether the SIZE argument is valid.  It must be a power of
>       two multiple of sizeof (void *).  */
>    if (alignment % sizeof (void *) != 0
> -      || !powerof2 (alignment / sizeof (void *)) != 0
> +      || !powerof2 (alignment / sizeof (void *))
>        || alignment == 0)
>      return EINVAL;
>  
> 

c.