<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - long double is suboptimal on WebAssembly"
href="https://bugs.llvm.org/show_bug.cgi?id=36038">36038</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>long double is suboptimal on WebAssembly
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: WebAssembly
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ncw@realvnc.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Wasm provides "long double" as an emulated 128-bit double, using the
compiler-rt library.
This is excessive precision for most applications, and a previous discussion
(which I can't find now...) in a GitHub thread indicated that several Wasm
contributors thought it would be better to simply provide 64-bit floats on
Wasm.
The argument was, "anyone who really needs 128-bit floats is writing rather
unusual software, and can use a library".
Using 128-bit long doubles is a long-term ABI commitment, which incurs overhead
in any application that uses snprintf or other such functions.
I don't believe this change is recorded elsewhere in Bugzilla.
(See PR35582 for another similar ABI change, int_fast16_t, and PR33337 for
changing size_t to long.)</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>