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<p>That can't happen or won't benefit much, before the compiler
supports super-natual alignments. So there's a deeper level of
support needed.<br>
<br>
And personally I don't think that's the right long term direction.
It takes a long time to develop and maintain this stuff and you
never know what the market will look like in 10 years.<br>
ARM has SVE, and RISC-V has the upcoming vector extension which
will move far away from the traditional SIMD stuff.<br>
<br>
Compiler support for block vectorization has rarely paid off
really well given the amount of work that needs to go into it. So
maybe it's better to wait for the next iteration :)<br>
</p>
<div class="moz-cite-prefix">On 4/6/19 11:13 PM, Ben Grasset wrote:<br>
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<blockquote type="cite"
cite="mid:CAL4d7FgXf48q-j9UpcaN3_xG3XkTBisw_UiORFAt_AHtmp04bg@mail.gmail.com">
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<div dir="ltr">On Wed, Mar 27, 2019 at 11:32 AM J. Gareth
Moreton <<a href="mailto:gareth@moreton-family.com"
moz-do-not-send="true">gareth@moreton-family.com</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
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<div>So with the false start that was pure inline
assembly, I like to talk about how to move forward with
FPC, or at least with x86_64.</div>
</blockquote>
<div><br>
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<div>It occurred to me today, aren't you the person who
fixed the -Sv compiler flag so that it actually works? I'd
say expansion on that functionality would be more widely
useful than just about anything else I can think of with
regards to optimization (because it's so easy to use, and
yet so powerful.)</div>
<div><br>
</div>
<div>Maybe start with making it fully use AVX instructions
for the operations? IIRC, currently, even if you use the
AVX or AVX2 compiler flags, it will always generate stuff
like this:</div>
<div><br>
</div>
<div>
<div>vmovups<span style="white-space:pre"> </span>(%rdx),%xmm0</div>
<div>addps<span style="white-space:pre"> </span>(%r8),%xmm0</div>
<div>vmovups<span style="white-space:pre"> </span>%xmm0,(%rax)</div>
</div>
<div><br>
</div>
<div>rather than using vaddps.</div>
<div><br>
</div>
<div>From there you could make it support arrays larger than
4 elements, e.t.c....</div>
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