<html>
<head>
<base href="https://bugs.freedesktop.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 - dEQP-GLES3: modf does not produce correct results with infinities"
href="https://bugs.freedesktop.org/show_bug.cgi?id=89645">89645</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>dEQP-GLES3: modf does not produce correct results with infinities
</td>
</tr>
<tr>
<th>Product</th>
<td>Mesa
</td>
</tr>
<tr>
<th>Version</th>
<td>git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>Drivers/DRI/i965
</td>
</tr>
<tr>
<th>Assignee</th>
<td>idr@freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>itoral@igalia.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=114429" name="attach_114429" title="Fixes modf with infinities by adding a conditional at the IR level">attachment 114429</a> <a href="attachment.cgi?id=114429&action=edit" title="Fixes modf with infinities by adding a conditional at the IR level">[details]</a></span>
Fixes modf with infinities by adding a conditional at the IR level
List of affected tests:
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.lowp_vertex
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.lowp_fragment
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.mediump_vertex
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.mediump_fragment
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.highp_vertex
dEQP-GLES3.functional.shaders.builtin_functions.precision.modf.highp_fragment
The problem is that Mesa implements modf as trunc to get the integer part, then
subtracts that from the parameter to obtain the remainder and that gives a NaN
instead of 0. I tried calculating the remainder directly with ir_unop_fract but
that also gives as NaN as result, so it looks like there is no way around this
issue.
Of course, we can add a conditional check to modf in order to detect this case
specifically and solve it directly, but that would hurt all emissions of the
function, so I am not sure that we want to do this. Attached is a patch that
does this at the IR level (even if we want to do this maybe we want to do it
inside i965, not sure) and fixes the tests.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the QA Contact for the bug.</li>
</ul>
</body>
</html>