<html>
<head>
<base href="http://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 - Address space 8388355 should not be generic in C++"
href="http://bugs.llvm.org/show_bug.cgi?id=32662">32662</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Address space 8388355 should not be generic in C++
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</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>Frontend
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>pkeir@outlook.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=18286" name="attach_18286" title="A MWE similar to the example described">attachment 18286</a> <a href="attachment.cgi?id=18286&action=edit" title="A MWE similar to the example described">[details]</a></span>
A MWE similar to the example described
LLVM supports address space annotation such as:
__attribute__((address_space(42))) int *p;
A most useful aspect of their functionality is knowing that such pointers
cannot be converted to one another. For example, this static assert passes:
using pt1 = __attribute__((address_space(1))) int *;
using pt2 = __attribute__((address_space(2))) int *;
static_assert(!std::is_convertible<pt0,pt1>::value,"");
Though this functionality has many uses within standard C++, LLVM's OpenCL
implementation also uses this feature. Since around Clang 3.9, however, an
aspect particular to OpenCL appears when compiling C++. This aspect should
rather rely on the user specifying explicitly that OpenCL is to be compiled;
perhaps via "-x cl -cl-std=CL2.0".
Address space 8388355 is used by Clang to implement the generic address space
added in OpenCL 2.0. In C++, converting a pointer targeting address space
8388355 should behave the same as pointers targeting other address spaces: it
should not be convertible.
As a concrete example, the following should not produce an error, but as of
Clang 3.9 it does:
using pt1 = __attribute__((address_space(1))) int *;
using pt2 = __attribute__((address_space(2))) int *;
using pt8388355 = __attribute__((address_space(8388355))) int *;
static_assert(!std::is_convertible<pt0,pt8388355>::value,"");
static_assert(!std::is_convertible<pt1,pt8388355>::value,"");</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>