Re: -mno-fancy-math-387 doesn't work with -mpentium3

Re: -mno-fancy-math-387 doesn't work with -mpentium3

[Roger Sayle]

Hi H.J.,

This is the documented behaviour of "-mno-fancy-math-387".

> -mno-fancy-math-387
> Some 387 emulators do not support the sin, cos and sqrt instructions
> for the 387.  Specify this option to avoid generating those
> instructions.  This option is the default on FreeBSD, OpenBSD and
> NetBSD.  This option is overridden when -march indicates that the
> target cpu will always have an FPU and so the instruction will not
> need emulation.  As of revision 2.6.1, these instructions are not
> generated unless you also use the -funsafe-math-optimizations switch.

As the pentium3 has an FPU, this option has no effect.  I take
it you have a case where you'd like to generate optimized code
but without using fsin, fcos and fsqrt on the pentium III?

Perhaps "-fno-builtin-sin -fno-builtin-cos -fno-builtin-sqrt"?

Roger
--
Roger Sayle,                         E-mail: roger@eyesopen.com
OpenEye Scientific Software,         WWW: http://www.eyesopen.com/
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