Neil Ferguson <nferguso@xxxxxxx> writes:
> Whilst reading the GCC man page documentation for the -mfpmath option,
> I came across this sentence for -mfpmath=sse:
>
> > The resulting code should be considerably faster in the major-
> > ity of cases and avoid the numerical instability problems of
> > 387 code, but may break some existing code that expects tempo-
> > raries to be 80bit.
>
> Can someone point me to a description of these "numerical instability
> problems of 387 code", please?
>
> I've searched the GCC site & mailing lists, and I've searched with
> Google, but I can't find anything that details the particular concerns
> that led to this note in the manual. All I can find is a list message
> containing the patch that put it into the man page.
See, e.g.,
http://gcc.gnu.org/PR323
and the many PRs which have been marked as a duplicate of that one.
Ian
