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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - Add FP64 support to the i965 shader backends"
href="https://bugs.freedesktop.org/show_bug.cgi?id=92760#c34">Comment # 34</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - Add FP64 support to the i965 shader backends"
href="https://bugs.freedesktop.org/show_bug.cgi?id=92760">bug 92760</a>
from <span class="vcard"><a class="email" href="mailto:siglesias@igalia.com" title="Samuel Iglesias <siglesias@igalia.com>"> <span class="fn">Samuel Iglesias</span></a>
</span></b>
<pre>(In reply to Connor Abbott from <a href="show_bug.cgi?id=92760#c33">comment #33</a>)
<span class="quote">> (In reply to Samuel Iglesias from <a href="show_bug.cgi?id=92760#c32">comment #32</a>)
> > I found an issue related to the opt_algebraic passes after we lowered lrp
> > instruction when it has double-based types as arguments (lrp instruction
> > does not support doubles in BDW).
> >
> > Currently, the lowering of double ops run as part the optimization loop in
> > nir_optimize(). In that lowering function, I converted the lrp to its
> > equivalent mathematical function when we have doubles as arguments... which
> > is reverted by opt_algebraic() in next iteration of the optimization loop :-)
> >
> > My idea is: remove my lrp's lowering pass, add a new flag in
> > nir_shader_compiler_options called 'lower_lrp_doubles' and modify
> > nir_opt_algebraic.py to run its lrp's lowering when the arguments are
> > doubles, if that flag is enabled. Any driver that does not support lrp with
> > double arguments, just enable that nir option in its configuration.
> >
> > I would like to know your opinion about this solution before implementing
> > it. Do you have other solutions in mind?
> >
> > Thanks!
>
> That seems like a fine solution -- we already do similar things in a number
> of different places in opt_algebraic. Just keep in mind that you'll have to
> disable the lrp optimization in opt_algebraic for doubles when that option
> is enabled to avoid running into the same problem.</span >
OK, thanks Connor!</pre>
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