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<div class="moz-cite-prefix">On 4/7/19 12:16 AM, Ben Grasset wrote:<br>
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<div dir="ltr">On Sat, Apr 6, 2019 at 5:27 PM Jeppe Johansen
<<a href="mailto:jeppe@j-software.dk"
moz-do-not-send="true">jeppe@j-software.dk</a>> wrote:<br>
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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.</p>
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<div>I'm fairly confident the existing functionality could be
improved upon in a useful way. Gareth has already done so in
the past.</div>
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Perhaps but it's a nightmare in so many places to satisfy
requirements for potential uses. Ideally the programmer would
specify minimum alignment requirements per type<br>
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<div> On Sat, Apr 6, 2019 at 5:27 PM Jeppe Johansen <<a
href="mailto:jeppe@j-software.dk" moz-do-not-send="true">jeppe@j-software.dk</a>>
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<p>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.</p>
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<div>I sincerely doubt I will be using a RISC-V based
desktop PC in 10 years. Also nobody said -Sv could not
also be extended to stuff such as ARM Neon at some point
down the line if someone was up to it. One thing at a time
though.</div>
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<p>It's too hard to say, and the RISC-V foundation has made really
bad decisions that will prevent them from getting a good start.</p>
<p>But you will not find anyone who don't think vector extensions
are better for software than SIMD. ARM SVE and RISC-V Vector
extensions are true vector extensions, whereas the SSE, AVX,
NEON, Advanced SIMD, etc are packed SIMD extensions requiring a
ton of hoops and jumps to use in real block vectorized code<br>
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<div dir="ltr">On Sat, Apr 6, 2019 at 5:27 PM Jeppe
Johansen <<a href="mailto:jeppe@j-software.dk"
moz-do-not-send="true">jeppe@j-software.dk</a>>
wrote:<br>
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<p>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 :) </p>
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<div>It very objectively pays off in every compiler that
has it. I don't think "it's too hard" is a good
excuse. I made my previous comment because it seems
like Gareth if anyone specifically does *not* think it
is too hard.<br>
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Do you have any quantifiable data to point at here?<br>
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