Re: docs: document early break support and pragma novector

[Richard Biener]

On Tue, 16 Apr 2024, Tamar Christina wrote:

> docs: document early break support and pragma novector

OK.

> ---
> diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html
> index 
> b4c602a523717c1d64333e44aefb60ba0ed02e7a..aceecb86f17443cfae637e90987427b98c42f6eb
>  100644
> --- a/htdocs/gcc-14/changes.html
> +++ b/htdocs/gcc-14/changes.html
> @@ -200,6 +200,34 @@ a work-in-progress.</p>
>      for indicating parameters that are expected to be null-terminated
>      strings.
>    </li>
> +  <li>
> +    The vectorizer now supports vectorizing loops which contain any number 
> of early breaks.
> +    This means loops such as:
> +    <pre>
> +     int z[100], y[100], x[100];
> +     int foo (int n)
> +     {
> +       int res = 0;
> +       for (int i = 0; i < n; i++)
> +         {
> +            y[i] = x[i] * 2;
> +            res += x[i] + y[i];
> +
> +            if (x[i] > 5)
> +              break;
> +
> +            if (z[i] > 5)
> +              break;
> +
> +         }
> +       return res;
> +     }
> +    </pre>
> +    can now be vectorized on a number of targets.  In this first version any
> +    input data sources must either have a statically known size at compile 
> time
> +    or the vectorizer must be able to determine based on auxillary 
> information
> +    that the accesses are aligned.
> +  </li>
>  </ul>
>  <!-- .................................................................. -->
>  <h2 id="languages">New Languages and Language specific improvements</h2>
> @@ -231,6 +259,9 @@ a work-in-progress.</p>
>    previous options <code>-std=c2x</code>, <code>-std=gnu2x</code>
>    and <code>-Wc11-c2x-compat</code>, which are deprecated but remain
>    supported.</li>
> +  <li>GCC supports a new pragma <code>&#x23;pragma GCC novector</code> to
> +      indicate to the vectorizer not to vectorize the loop annotated with the
> +      pragma.</li>
>  </ul>
>  
>  <h3 id="cxx">C++</h3>
> @@ -400,6 +431,9 @@ a work-in-progress.</p>
>        warnings are enabled for C++ as well</li>
>    <li>The DR 2237 code no longer gives an error, it emits
>        a <code>-Wtemplate-id-cdtor</code> warning instead</li>
> +  <li>GCC supports a new pragma <code>&#x23;pragma GCC novector</code> to
> +      indicate to the vectorizer not to vectorize the loop annotated with the
> +      pragma.</li>
>  </ul>
>  
>  <h4 id="libstdcxx">Runtime Library (libstdc++)</h4>
> 
> 
> 
> 
> 

-- 
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)