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<div class="moz-cite-prefix">On 10/30/2014 09:58 PM, deadal nix
wrote:<br>
</div>
<blockquote
cite="mid:CANGV3T3FEd3jjH_10XJPChkZZt+Yo0m5UtFpeC8Hw0FedYd7ug@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-10-30 21:52 GMT-07:00 Hal Finkel
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">----- Original Message -----<br>
> From: "deadal nix" <<a moz-do-not-send="true"
href="mailto:deadalnix@gmail.com">deadalnix@gmail.com</a>><br>
> To: "Philip Reames" <<a moz-do-not-send="true"
href="mailto:listmail@philipreames.com">listmail@philipreames.com</a>><br>
> Cc: "Chandler Carruth" <<a
moz-do-not-send="true"
href="mailto:chandlerc@google.com">chandlerc@google.com</a>>,
"Hal Finkel" <<a moz-do-not-send="true"
href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>>,
"llvm-commits"<br>
> <<a moz-do-not-send="true"
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a>><br>
> Sent: Thursday, October 30, 2014 11:45:12 PM<br>
> Subject: Re: Add a pass to convert aggregate
loads/stores into scalar load stores<br>
><br>
</span><span class="">> Option 4 - Transform to series
of smaller integer loads<br>
> - This appears to be what this patch implements.
Not entirely sure<br>
> why this was chosen.<br>
><br>
><br>
> Yes, this is what this diff is doing.<br>
><br>
><br>
> This option allow to keep pointerness of
load/stores (it could be<br>
> refined in this patch, but the idea is there). It
also avoid to<br>
> generate a bunch of small load when a big load
would suffice.<br>
><br>
><br>
> Making a big load of iN (option 2) is also
reasonable, but in this<br>
> case, the load won't respect the target alignment's
constraints. I<br>
> thought it was a problem so I went for the option 3
instead.<br>
<br>
</span>You can manually set the alignment on the load to
be whatever you need (down to align 1).<br>
<span class="HOEnZb"><font color="#888888"><br>
-Hal<br>
</font></span><span class="im HOEnZb"><br>
</span></blockquote>
<div><br>
</div>
<div>I wasn't sure how well it is supported and wanted to
avoid to open a new can of worms. If you think this is a
better approach, I can update the diff in that direction.<br>
</div>
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</blockquote>
I would not advice investing effort in revising the existing patch
until we settle on an overall approach. <br>
<br>
p.s. Feel free to argue in favor of the current approach. The "it's
here and works, even if not ideal" argument is a worthy one which
hasn't really been made. <br>
<br>
Philip<br>
<br>
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