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Re: [PATCH] Optimise the fpclassify builtin to perform integer operations when possible
On Tue, 13 Sep 2016, Tamar Christina wrote:
>
>
> On 12/09/16 23:33, Joseph Myers wrote:
> > Why is this boolean false for ieee_quad_format, mips_quad_format and
> > ieee_half_format? They should meet your description (even if the x86 /
> > m68k "extended" formats don't because of the leading mantissa bit being
> > set for infinities).
> >
> Ah, I played it a bit too safe there. I will change this and do some
> re-testing and update the patch.
It occurred to me that there might be an issue with your approach of
overlaying the floating-point value with a single integer, when the quad
formats are used on 32-bit systems where TImode isn't fully supported as a
scalar mode. However, if that's an issue the answer isn't to mark the
formats as non-IEEE, it's to support ORing together the relevant parts of
multiple words when determining whether the mantissa is nonzero (or some
equivalent logic).
--
Joseph S. Myers
joseph@codesourcery.com