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Re: The state of glibc libm
Uros Bizjak <ubizjak@gmail.com> writes:
> Hello!
>
>>>> SSE ABI entries for i?86 in glibc were rejected. ?I proposed them like
>>>> 4-5 years ago to make -mfpmath=sse not suck.
>>>
>>> With the new libm hopefully this can be revisited.
>>>
>>> But there's the ABI and there's the internal implementation.
>>>
>>> My point was just that relying on x87 fully again does not really make
>>> sense anymore in 2012.
>>
>> That's true, the return value shuffle to/from the x87 stack might not be
>> too bad for performance, nor argument passing on the stack.
>
> Can this issue be solved with alternative function entry points, in
> the same way ICC does? This way, we can pass values in SSE, not on the
> stack.
Passing values in SSE is a big win, especially on some CPUs like Atom.
You can just annotate math.h (possibly with different entry names, so that
someone not including it doesn't get totally bogus results)
-Andi
--
ak@linux.intel.com -- Speaking for myself only