#pragma clang loop - documentation

[Dmitri Gribenko]

On Wed, Jun 11, 2014 at 2:20 AM, Tyler Nowicki <tnowicki at apple.com> wrote:
> Hi,
>
> Here is a patch for the loop hints documentation. I’m not exactly sure if I wrote the attribute documentation correctly. If I missed something please let me know.

> +Extensions for loop hint optimizations
> +======================================
> +
> +The ``#pragma clang loop`` directive is used to specify hints for optimizing the
> +subsequent for, while, do-while, or c++11 range-based for loop. The directive
> +provides options for controlling vectorization, interleaving, and unrolling.

This documentation describes syntax and the high-level effect of the
pragma, but it does not explain what are the semantic constraints on
the loop.  Users would want to know when it is valid to apply the
pragma, and the documentation does not explain that.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/