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<div class="moz-cite-prefix">On 12/5/2018 5:47 PM, David Jones
wrote:<br>
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cite="mid:CAPOMCaG-Rvf3BnLi+qsurePOsbh6jgUfBzHrgwnjCfWmPsVCVw@mail.gmail.com">
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<div dir="ltr">On Wed, Dec 5, 2018 at 5:40 PM Sanjay Patel
<<a href="mailto:spatel@rotateright.com"
moz-do-not-send="true">spatel@rotateright.com</a>>
wrote:<br>
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<div dir="auto">Hi David,</div>
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<div dir="auto">Thanks for reporting the problem. I don’t
have any guesses as to how this could cause OOM. Cc’ing
some people that might.</div>
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<div>+a few more, thanks! :-)</div>
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<div dir="auto">If the problem is only showing up on PPC,
a quick hack would be to add a TLI hook and disable the
transform for PPC. I’d prefer that to a full revert
(especially since I’ve already enhanced this code to
handle some vectors, and another enhancement is in
progress)...unless we have a test case that shows it’s
not a PPC-specific bug?</div>
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<div>Agreed on avoiding a revert... this looks like a pretty
hard-fought change, based on <a
href="https://bugs.llvm.org/show_bug.cgi?id=32023"
moz-do-not-send="true">https://bugs.llvm.org/show_bug.cgi?id=32023</a>.</div>
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<div>I do believe this is PPC-specific (although, as is
often the case, your change may simply be tickling a bug
somewhere else).</div>
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<p>If it's PPC-specific, my first guess here would be there's some
PowerPC-specific target combine that's trying to combine the
opposite way, or something like that. Assuming that's the case,
it probably runs out of memory pretty quickly, so it should be
fast to bisect if you restrict the memory usage with ulimit.<br>
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<p>-Eli<br>
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<pre class="moz-signature" cols="72">--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project</pre>
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