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<div class="moz-cite-prefix">On 05/25/2018 02:01 PM, Friedman, Eli
via cfe-dev wrote:<br>
</div>
<blockquote type="cite"
cite="mid:25e7b79a-c309-7d7a-42d3-130677045b94@codeaurora.org">
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<div class="moz-cite-prefix">On 5/25/2018 11:46 AM, JF Bastien
wrote:<br>
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<blockquote type="cite"
cite="mid:7A085E79-CC0C-4709-8405-2F2032DFDC3F@apple.com"> <br
class="">
<div><br class="">
<blockquote type="cite" class="">
<div class="">On May 25, 2018, at 11:38 AM, Friedman, Eli
<<a href="mailto:efriedma@codeaurora.org" class=""
moz-do-not-send="true">efriedma@codeaurora.org</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div text="#000000" bgcolor="#FFFFFF" class="">
<div class="moz-cite-prefix">On 5/25/2018 11:29 AM, JF
Bastien via cfe-dev wrote:<br class="">
</div>
<blockquote type="cite"
cite="mid:AC7AF159-592E-4EA7-9AA4-A8242D750526@apple.com"
class="">
<div class="">
<div class="">
<ol class="MailOutline">
<li class="">Teach the target infrastructure
that hardware interference size is something
they can specify (in tablegen files
somewhere).</li>
<li class="">Allow overriding the value in
sub-targets using -march or -mcpu (the
sub-target defines the numeric value, and the
user gets the overriden one by using -march or
-mcpu).</li>
</ol>
</div>
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</blockquote>
<br class="">
We can't change the value based on -mcpu. We generally
allow mixing code built with different values of -mcpu.
And any code which is linked together must use the same
value for hardware_destructive_interference_size, or
else we violate ODR.<br class="">
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<div><br class="">
</div>
<div>Interesting point. The case I’d like to cover is one
where the developer wants to get the exact right value for
their particular CPU, instead of a conservative answer with
extra padding. How do you think we should meet this use
case?</div>
<br class="">
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</blockquote>
<br>
Go back to the standards committee and ask for a function that
isn't constexpr? I can't think of any other reasonable solution.<br>
</blockquote>
<br>
Unfortunately, to define structure layouts they need to be constant.<br>
<br>
The best solution I've thought of is to extend the abi_tag support
to force the mangling of interfaces depending on values of these
constructs to be different.<br>
<br>
-Hal <br>
<br>
<blockquote type="cite"
cite="mid:25e7b79a-c309-7d7a-42d3-130677045b94@codeaurora.org"> <br>
-Eli<br>
<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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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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