diff mbox series

[GCC-12] Mention O2 vectorization enabling.

Message ID 20211008072911.86497-1-hongtao.liu@intel.com
State New
Headers
Series [GCC-12] Mention O2 vectorization enabling. |

Commit Message

Liu, Hongtao Oct. 8, 2021, 7:29 a.m. UTC 
  ---
 htdocs/gcc-12/changes.html | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Richard Biener Oct. 8, 2021, 11:18 a.m. UTC | #1 
On Fri, Oct 8, 2021 at 9:29 AM liuhongt via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> ---
>  htdocs/gcc-12/changes.html | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/htdocs/gcc-12/changes.html b/htdocs/gcc-12/changes.html
> index 22839f2d..6e898db7 100644
> --- a/htdocs/gcc-12/changes.html
> +++ b/htdocs/gcc-12/changes.html
> @@ -68,6 +68,15 @@ a work-in-progress.</p>
>  <!-- .................................................................. -->
>  <h2 id="general">General Improvements</h2>
>
> +<ul>
> +  <li>The vectorization is enabled in <code>-O2</code>, now <code>-O2</code> is

Vectorization is enabled at <code>-O2</code> which is now equivalent to the
original ...

> +      equivalent to the original <code>-O2 -ftree-vectorize
> +      -fvect-cost-model=very-cheap</code>. Note that default vect cost model has

Note that the default vectorizer cost model

> +      been changed which may have a subtle effect, for example for the case with
> +      <code>-O2 -fopenmp #pragma omp parallel for simd</code>.

.. which used to behave as <code>-fvect-cost-model=cheap</code> were specified.

OK with those changes.

Richard.

> +  </li>
> +</ul>
> +
>  <!-- .................................................................. -->
>  <h2 id="languages">New Languages and Language specific improvements</h2>
>
> --
> 2.18.1
>
diff mbox series

Patch

diff --git a/htdocs/gcc-12/changes.html b/htdocs/gcc-12/changes.html
index 22839f2d..6e898db7 100644
--- a/htdocs/gcc-12/changes.html
+++ b/htdocs/gcc-12/changes.html
@@ -68,6 +68,15 @@  a work-in-progress.</p>
 <!-- .................................................................. -->
 <h2 id="general">General Improvements</h2>
 
+<ul>
+  <li>The vectorization is enabled in <code>-O2</code>, now <code>-O2</code> is
+      equivalent to the original <code>-O2 -ftree-vectorize
+      -fvect-cost-model=very-cheap</code>. Note that default vect cost model has
+      been changed which may have a subtle effect, for example for the case with
+      <code>-O2 -fopenmp #pragma omp parallel for simd</code>.
+  </li>
+</ul>
+
 <!-- .................................................................. -->
 <h2 id="languages">New Languages and Language specific improvements</h2>