Introduce [parallel.simd.copy]

Author: jaredhoberock

data_parallel_types.html

@@ -1348,6 +1348,42 @@ <h1><ins><code>simd</code> constructors</ins></h1>
         </cxx-remarks>
       </cxx-function>
     </cxx-section>
+
+    <cxx-section id="parallel.simd.copy">
+      <h1><ins><code>simd</code> copy functions</ins></h1>
+
+        <cxx-function>
+          <cxx-signature><ins>template&lt;class U, class Flags&gt; void copy_from(const U* mem, Flags);</ins></cxx-signature>
+
+          <cxx-requires>
+          <ins>
+            If the template parameter <code>Flags</code> is <code>vector_aligned_tag</code>, <code>mem</code> shall point to storage aligned by <code>memory_alignment_v&lt;simd, U&gt;</code>. If the template parameter <code>Flags</code> is <code>overaligned_tag&lt;N&gt;</code>, <code>mem</code> shall point to storage aligend by <code>N</code>. If the template parameter <code>Flags</code> is <code>element_aligned_tag</code>, <code>mem</code> shall point to storage aligned by <code>alignonf(U)</code>. <code>[mem, mem + size())</code> is a valid range.
+          </ins>
+          </cxx-requires>
+
+          <cxx-effects>
+          <ins>
+            Replaces the elements of the <code>simd</code> object such that the <em>i</em>-th element is assigned with <code>static_cast&lt;T&gt;(mem[i])</code> for all <code>i</code> &#8714; <code>[0, size())</code>.
+          </ins>
+          </cxx-effects>
+
+          <cxx-remarks>
+          <ins>
+            This function shall not participate in overload resolution unless
+
+            <bl>
+              <li>
+                <code>is_simd_flag_type_v&lt;Flags&gt;</code> is <code>true</code>, and
+              </li>
+
+              <li>
+                <code>U</code> is a vectorizable type.
+              </li>
+            </bl>
+          </ins>
+          </cxx-remarks>
+        </cxx-function>
+    </cxx-section>
   </cxx-section>
 </cxx-clause>