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<p>I think carter has it still right that it happens in the
backends.</p>
<p>If a new backend doesn't support these we could move this up into
Cmm though without much issue I think.<br>
</p>
<div class="moz-cite-prefix">Am 28/10/2021 um 23:12 schrieb Carter
Schonwald:<br>
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cite="mid:CAHYVw0ymoYp_F8z0zjJ7rfeypDzt_R+J-ohwMQ3N8cWvBvON2g@mail.gmail.com">
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<div dir="ltr">I think thats done on a per backend basis (though
theres been a lot of changes since i last looked at some of the
relevent pieces). (i'm actually based in Cambridge MA for the
next 1-2 years if you wanna brain storm IRL sometime)<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Thu, Oct 28, 2021 at 4:59
PM Norman Ramsey <<a href="mailto:nr@cs.tufts.edu"
moz-do-not-send="true" class="moz-txt-link-freetext">nr@cs.tufts.edu</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On
x86, GHC can translate 8-bit and 16-bit operations directly<br>
into the 8-bit and 16-bit machine instructions that the
hardware<br>
supports. But there are other platforms on which the smallest<br>
unit of arithmetic may be 32 or even 64 bits. Is there a
central<br>
module in GHC that can take care of rewriting 8-bit and 16-bit
operations<br>
into 32-bit or 64-bit operations? Or is each back end on its
own<br>
for this?<br>
<br>
(One of my students did some nice work on implementing this
transformation<br>
with a minimal set of sign-extension and zero-extension
operations:<br>
<a href="https://www.cs.tufts.edu/~nr/pubs/widen.pdf"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://www.cs.tufts.edu/~nr/pubs/widen.pdf</a>.)<br>
<br>
<br>
Norman<br>
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