<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - Rejects valid subscript expression on array of unknown bound in constant expression"
href="https://bugs.llvm.org/show_bug.cgi?id=48402">bug 48402</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>WONTFIX
</td>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - Rejects valid subscript expression on array of unknown bound in constant expression"
href="https://bugs.llvm.org/show_bug.cgi?id=48402#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED WONTFIX - Rejects valid subscript expression on array of unknown bound in constant expression"
href="https://bugs.llvm.org/show_bug.cgi?id=48402">bug 48402</a>
from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
<pre>Expressions with undefined behavior are non-constant, and in particular it is
not possible to create an out-of-bounds array index in a constant expression.
It's not possible for a compiler to know whether your example has defined
behavior or not, so the only conservatively-correct thing we can do is reject.
I reported this to the C++ committee a few years back, and there was support
for rejecting cases such as this, but the standard hasn't yet been updated to
match.
Resolving WONTFIX for now: the behavior is intentional, and we expect the
standard to change to match. But this will be revisited if the standard goes in
a different direction.</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>