<ul class="small-gap">
<li><a class="reference internal" href="#potentially-fixable" id="id7">Potentially Fixable</a></li>
<li><a class="reference internal" href="#floating-point" id="id8">Floating-Point</a></li>
-<li><a class="reference internal" href="#hard-to-fix" id="id9">Hard to Fix</a></li>
+<li><a class="reference internal" href="#simd-vectors" id="id9">SIMD Vectors</a></li>
+<li><a class="reference internal" href="#hard-to-fix" id="id10">Hard to Fix</a></li>
</ul>
</li>
</ul>
function implementation isn’t, e.g. <code>std::min</code> and <code>std::max</code>), is
well-defined in the <em>pexe</em>.</li>
</ul>
+</section><section id="simd-vectors">
+<h4 id="simd-vectors">SIMD Vectors</h4>
+<p>SIMD vector instructions aren’t part of the C/C++ standards and as such
+their behavior isn’t specified at all in C/C++; it is usually left up to
+the target architecture to specify behavior. Portable Native Client
+instead exposed <a class="reference internal" href="/native-client/reference/pnacl-c-cpp-language-support.html#portable-simd-vectors"><em>Portable SIMD Vectors</em></a> and
+offers the same guarantees on these vectors as the guarantees offered by
+the contained elements. Of notable interest amongst these guarantees are
+those of alignment for load/store instructions on vectors: they have the
+same alignment restriction as the contained elements.</p>
</section><section id="hard-to-fix">
<h4 id="hard-to-fix">Hard to Fix</h4>
<ul class="small-gap">