gcc-13/changes.html - GCN: document -mlow-precision-sqrt

diff --git a/htdocs/gcc-13/changes.html b/htdocs/gcc-13/changes.html
index 390193ca..d335eab3 100644
--- a/htdocs/gcc-13/changes.html
+++ b/htdocs/gcc-13/changes.html
@@ -179,6 +179,12 @@ a work-in-progress.</p>
   <li>Support for the Instinct MI200 series devices (<a
       href="https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html">
       <code>gfx90a</code></a>) has been added.</li>
+  <li>The <code>-mlow-precision-sqrt</code> option (disabled by default)
+      has been added to use the hardware <code>sqrt</code> also for
+      double-precision floating point arguments; note that the result
+      only has much a reduced accurary of 2<sup>29</sup> ULP. This
+      option requires <code>-funsafe-math-optimizations</code>
+      (implied by <code>-ffast-math</code>) in addition.</li>
 </ul>
 
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