On Wed, 25 Oct 2017, vladimir.mezent...@oracle.com wrote: > On 10/25/2017 10:28 AM, Joseph Myers wrote: > > On Wed, 25 Oct 2017, vladimir.mezent...@oracle.com wrote: > > > >> +# Disable FMA (floating-point multiply-add) instructions for complex > >> division. > >> +# These instructions can produce different result if two operations > >> executed separately. > >> +LIBGCC2_FFP_CONTRAST_CFLAGS = -ffp-contract=off > >> +LIB2_DIV3_FUNCS = _divdc3 _divhc3 _divsc3 > > Without regard to whether the change is appropriate in the first place, > > I'm doubtful of the logic for selecting floating-point modes. I'd expect > > something that applies to all floating-point modes. Even if nothing has > > fused XFmode operations, some architectures (e.g. s390, powerpc) have > > fused operations on TFmode / KFmode. > > Hello Joseph and GCC-team, > Different people are giving me different directions. > I am glad to change my fix but please provide clear directions on how > you want to see it.
I am unconvinced of the need for a change that reduces accuracy in some cases to make things less surprising in other cases. I am clear that if there is to be such a change, it should be made consistently for all affected floating-point modes, including TFmode / KFmode where available, since those have fused operations on some platforms. -- Joseph S. Myers jos...@codesourcery.com
