While DI <-> BF conversions can be handled (and are) through
DI <-> XF <-> BF and for narrower integral modes even sometimes
through DF or SF, because XFmode has 64-bit mantissa and so all
the DImode values are exactly representable in XFmode.
That is not the case for TImode, and while e.g. the HF -> TI
conversions are IMHO useless in libgcc, because HFmode has
-65504.0f16, 65504.0f16 range, all the integers will be already
representable in SImode (or even HImode for unsigned) and so
I think HF -> DI -> TI conversions are faster and valid,
BFmode has roughly the same range as SFmode and so we absolutely need
the TI -> BF conversions to avoid double rounding.
As for BF -> TI conversions, they can be either also implemented
in libgcc, or they can be implemented (as done in this commit)
as BF -> SF -> TI conversions with the same code generation used
elsewhere, just doing the 16-bit left shift of the bits - I think
we don't need to handle sNaNs during the BF -> SF part because
SF -> TI (which is already a libcall too) will handle that too.
The BF -> SF -> TI path avoids wasting
32: 0000000000015e10 321 FUNC GLOBAL DEFAULT 13 __fixbfti@@GCC_13.0.0
89: 0000000000015f60 299 FUNC GLOBAL DEFAULT 13 __fixunsbfti@@GCC_13.0.0
2023-03-10 Jakub Jelinek <jakub@redhat.com>
PR target/107703
* optabs.cc (expand_fix): For conversions from BFmode to integral,
use shifts to convert it to SFmode first and then convert SFmode
to integral.
* soft-fp/floattibf.c: New file.
* soft-fp/floatuntibf.c: New file.
* config/i386/libgcc-glibc.ver: Export __float{,un}tibf @ GCC_13.0.0.
* config/i386/64/t-softfp (softfp_extras): Add floattibf and
floatuntibf.
(CFLAGS-floattibf.c, CFLAGS-floatunstibf.c): Add -msse2.
246127ab23