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<div class="moz-cite-prefix">On 08/20/2016 12:56 PM, Daniel Berlin
wrote:<br>
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cite="mid:CAF4BwTVrjzK=QdxukoA5=BRvkWrkF=Xbb=QGsP=15+Px28wLNA@mail.gmail.com"
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<div dir="ltr">It is already enabled by default for GVNHoist,
which is enabled by default at O1 and O2.
<div>There are patches in progress to convert other passes under
review.</div>
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Like I said, haven't been following along. This is a lot better
progress than I'd realized and greatly diminishes my concern, <br>
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<div>We just branched for 3.9, and are in the midst of
significant pass manager work, so i am not sure having a
super-near term date makes sense?</div>
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If we already have MemorySSA on by default, I think you've already
passed the threshold I was most worried about. There's a huge
difference between "we've got this new thing which which solve all
problems, but isn't yet available", and "we've got this new thing
which is already in use and we need to port this to". <br>
<br>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Aug 20, 2016 at 12:54 PM,
Philip Reames <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:listmail@philipreames.com" target="_blank">listmail@philipreames.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">On 08/20/2016 12:38 PM, Hal Finkel wrote:<br>
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hfinkel added a comment.<br>
<br>
In <a moz-do-not-send="true"
href="https://reviews.llvm.org/D23432#521624"
rel="noreferrer" target="_blank">https://reviews.llvm.org/D2343<wbr>2#521624</a>,
@reames wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0
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I am not actively objecting to this patch, but I
really don't like the overall direction here. Having
a threshold where our ability to optimize falls off a
cliff just seems really undesirable. As Hal pointed
out, there are likely options for summarizing alias
sets to allow quicker AA queries. How much have we
explored that design space?<br>
</blockquote>
<br>
My understanding from the discussion is that all uses of
the ASTracker are going to be replaced with
MemorySSA-based algorithms; that is why I was okay with
this (for now). If we still need an AST concept, then
we'll want to do something more sophisticated.<br>
</blockquote>
</span>
I haven't been following the MemorySSA work recently. Do we
have a concrete near term date in mind for enabling
MemorySSA? If not, I am not okay with an attitude of
"MemorySSA will fix everything... someday". That's a very
dangerous road to start walking down.<br>
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