diff mbox series

docs: document early break support and pragma novector

Message ID patch-18416-tamar@arm.com
State New
Headers show
Series docs: document early break support and pragma novector | expand

Commit Message

Tamar Christina April 16, 2024, 5:23 a.m. UTC 
docs: document early break support and pragma novector

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Comments

Richard Biener April 16, 2024, 6:59 a.m. UTC | #1 
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>
> 
> 
> 
> 
>
diff mbox series

Patch

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>