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<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - i965: Timeout in dEQP-GLES31.functional.ssbo.layout.random.all_shared_buffer.5"
href="https://bugs.freedesktop.org/show_bug.cgi?id=104271#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - i965: Timeout in dEQP-GLES31.functional.ssbo.layout.random.all_shared_buffer.5"
href="https://bugs.freedesktop.org/show_bug.cgi?id=104271">bug 104271</a>
from <span class="vcard"><a class="email" href="mailto:currojerez@riseup.net" title="Francisco Jerez <currojerez@riseup.net>"> <span class="fn">Francisco Jerez</span></a>
</span></b>
<pre>IMHO the ultimate reason for the regression is that the dataflow propagation
logic of the copy propagation pass has a serious run-time complexity problem in
acyclic CFGs. The patch this was bisected to is merely increasing the amount
of work done in each iteration which substantially exacerbates the problem. A
proper fix would involve reworking the copy propagation dataflow logic to
reduce the polynomial degree of its run-time complexity in the acyclic case.
Working on it -- It will likely give you better performance than before my
undef handling patch.
Updating importance to high-priority enhancement since this is purely a
(largely pre-existing) compile-time performance issue, spec conformance is
unaffected by it.</pre>
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