On Mon, Jan 21, 2019 at 5:56 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > On Mon, Jan 21, 2019 at 8:43 AM Uros Bizjak <ubiz...@gmail.com> wrote: > > > > On Mon, Jan 21, 2019 at 5:15 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > > > > > TI->SF and TI->DF conversions in libgcc2.c: > > > > > > FSTYPE > > > FUNC (DWtype u) > > > { > > > ... > > > } > > > > > > have no rounding mode support. We should replace __floattisf, > > > __floattidf, > > > __floatuntisf and __floatuntidf in libgcc2.c with these from soft-fp. > > > > > > PR libgcc/88931 > > > * config/i386/64/t-softfp-compat (libgcc2-ti-functions): New. > > > (LIB2FUNCS_EXCLUDE): Likewise. > > > (libgcc2-ti-softp): Likewise. > > > (LIB2ADD): Likewise. > > > --- > > > libgcc/config/i386/64/t-softfp-compat | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/libgcc/config/i386/64/t-softfp-compat > > > b/libgcc/config/i386/64/t-softfp-compat > > > index 0978695c3a4..abb78032bf5 100644 > > > --- a/libgcc/config/i386/64/t-softfp-compat > > > +++ b/libgcc/config/i386/64/t-softfp-compat > > > @@ -13,3 +13,11 @@ libgcc2-tf-functions = _divtc3 _multc3 _powitf2 > > > LIB2FUNCS_EXCLUDE += $(libgcc2-tf-functions) > > > libgcc2-tf-compats = $(addsuffix .c, $(libgcc2-tf-functions)) > > > LIB2ADD += $(addprefix $(srcdir)/config/i386/64/, $(libgcc2-tf-compats)) > > > + > > > +# Replace _floatdisf, _floatdidf, _floatundisf and _floatundidf in > > > +# libgcc2.c, which have no rounding mode support, with floattisf.c, > > > +# floattidf.c, floatundisf.c and floatundidf.c from soft-fp. > > > +libgcc2-ti-functions = _floatdisf _floatdidf _floatundisf _floatundidf > > > +LIB2FUNCS_EXCLUDE += $(libgcc2-ti-functions) > > > +libgcc2-ti-softp = floattisf.c floattidf.c floatuntisf.c floatuntidf.c > > > +LIB2ADD += $(addprefix $(srcdir)/soft-fp/, $(libgcc2-ti-softp)) > > > > It is not that simple. Please note that libgcc2 functions use FP > > instructions in narrower mode (so, in effect still use FPU), while > > soft-fp functions don't even touch the FPU, and do everything using > > bit twiddling. I think that your change would introduce qoute > > noticeable runtime regressions. > > > > By "run-time regressions", did you mean performance or correctness?
Performance. Uros. > -- > H.J.