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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Add a NIR pass to lower indirects to conditional load/store operations."
href="https://bugs.freedesktop.org/show_bug.cgi?id=92929">92929</a>
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<th>Summary</th>
<td>Add a NIR pass to lower indirects to conditional load/store operations.
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Other
</td>
</tr>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>glsl-compiler
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<th>Assignee</th>
<td>idr@freedesktop.org
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<th>Reporter</th>
<td>jason@jlekstrand.net
</td>
</tr>
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<p>
<div>
<pre>One of the things that NIR is currently missing is a pass to lower indirect
load/store operations to if-ladders. For example, an indirect load on a
5-element array would be rewritten as
if (i < 2) {
if (i < 1) {
a = foo[0];
} else {
b = foo[1];
}
c = phi(a, b);
} else {
if (i < 3) {
d = foo[2];
} else {
if (i < 4) {
e = foo[3];
} else {
f = foo[4];
}
g = phi(e, f);
}
h = phi(d, g);
}
result = phi(c, h);
where the if-ladder effectively does a binary search over the space of possible
indirect values. Implementing this shouldn't be terribly hard from a compiler
theory perspective; it's mostly an exercise in recursion. Lots of recursion...</pre>
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