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<title>Issue 4280: simd::partial_load uses undefined identifier T</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#Ready">Tentatively Ready</a> status.</em></p>
<h3 id="4280"><a href="lwg-active.html#4280">4280</a>. <code class='backtick'>simd::partial_load</code> uses undefined identifier <code class='backtick'>T</code></h3>
<p><b>Section:</b> 29.10.8.7 <a href="https://wg21.link/simd.loadstore">[simd.loadstore]</a> <b>Status:</b> <a href="lwg-active.html#Ready">Tentatively Ready</a>
 <b>Submitter:</b> Tim Song <b>Opened:</b> 2025-06-21 <b>Last modified:</b> 2025-08-26</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Tentatively Ready">Tentatively Ready</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The <i>Effects:</i> element of <code class='backtick'>std::simd::partial_load</code> (after the latest rename) uses <code class='backtick'>T</code> 
but that is not defined anywhere. It should be <code class='backtick'>V::value_type</code>.
<p/>
Also, this paragraph should be a <i>Returns:</i> element.
</p>

<p><i>[2025-08-21; Reflector poll]</i></p>

<p>
Set status to Tentatively Ready after nine votes in favour during reflector poll.
</p>



<p id="res-4280"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N5008" title=" Working Draft, Programming Languages — C++">N5008</a>.
</p>

<ol>
<li><p>Modify 29.10.8.7 <a href="https://wg21.link/simd.loadstore">[simd.loadstore]</a> as indicated:</p>

<blockquote>
<pre><code>
template&lt;class V = <i>see below</i>, ranges::contiguous_range R, class... Flags&gt;
  requires ranges::sized_range&lt;R&gt;
  constexpr V partial_load(R&amp;&amp; r, flags&lt;Flags...&gt; f = {});
[&hellip;]
template&lt;class V = <i>see below</i>, contiguous_iterator I, sized_sentinel_for&lt;I&gt; S, class... Flags&gt;
  constexpr V partial_load(I first, S last, const typename V::mask_type&amp; mask,
                           flags&lt;Flags...&gt; f = {});
</code></pre>
<blockquote>
<p>
-6- [&hellip;]
<p/>
-7- <i>Mandates</i>: [&hellip;]
<p/>
-8- <i>Preconditions</i>: [&hellip;]
<p/>
-9- <del><i>Effects</i>: Initializes the</del><ins><i>Returns</i>: A <code class='backtick'>basic_simd</code> object 
whose</ins> <code><i>i</i></code><sup>th</sup> element <ins>is initialized</ins> with
<code>mask[<i>i</i>] &amp;&amp; <i>i</i> &lt; ranges::size(r) ? static_cast&lt;T&gt;(ranges::data(r)[<i>i</i>]) : T()</code> 
for all <code><i>i</i></code> in the range of <code>[0, V::size())</code><ins>, where <code class='backtick'>T</code> is <code class='backtick'>V::value_type</code></ins>.
<p/>
-10- <i>Remarks</i>: The default argument for template parameter <code class='backtick'>V</code> is <code>basic_simd&lt;ranges::range_value_t&lt;R&gt;&gt;</code>.
</p>
</blockquote>
</blockquote>
</li>

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