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? -- H.J.