On Thu, Jun 17, 2021 at 12:39:04PM -0500, Segher Boessenkool wrote: > On Tue, Jun 08, 2021 at 08:21:25PM -0400, Michael Meissner wrote: > > GCC will not convert ternary operations into using min/max instructions > > provided in this patch unless the user uses -Ofast or similar switches due > > to > > issues with NaNs. > > It will not do it because it is *incorrect* to do :-) > > (The RTL operators smin/smax are undefined for any NaN inputs (unless > both are the same bit pattern), and for different sign zeroes; it isn't > only NaNs even). > > > gcc/ > > 2021-06-08 Michael Meissner <meiss...@linux.ibm.com> > > > > * config/rs6000/rs6000.c (rs6000_emit_minmax): Add support for ISA > > 3.1 IEEE 128-bit floating point xsmaxcqp and xsmincqp > > instructions. > > Please don't randomly break lines. > > > --- a/gcc/config/rs6000/rs6000.c > > +++ b/gcc/config/rs6000/rs6000.c > > @@ -16103,7 +16103,8 @@ rs6000_emit_minmax (rtx dest, enum rtx_code code, > > rtx op0, rtx op1) > > /* VSX/altivec have direct min/max insns. */ > > if ((code == SMAX || code == SMIN) > > && (VECTOR_UNIT_ALTIVEC_OR_VSX_P (mode) > > - || (mode == SFmode && VECTOR_UNIT_VSX_P (DFmode)))) > > + || (mode == SFmode && VECTOR_UNIT_VSX_P (DFmode)) > > + || (TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode)))) > > The actual insns only check TARGET_POWER10 (so no TARGET_FLOAT128_HW). > Which is right, this or that?
It should include TARGET_FLOAT128_HW. The problem area is a power10 running in big endian mode and running 32-bit code. Because we don't have TImode, we can't enable the IEEE 128-bit hardware instructions. And because we don't have GLIBC support, we don't enable the FLOAT128 stuff by default on big endian. > > +/* { dg-require-effective-target ppc_float128_hw } */ > > +/* { dg-require-effective-target power10_ok } */ > > +/* { dg-options "-mdejagnu-cpu=power10 -O2 -ffast-math" } */ > > In testcases we can assume that float128_hw is set whenever we have a > p10; we don't manually disable it to make live hard for ourselves ;-) Again, I put it in case somebody builds a BE power10 compiler. > We could disallow disabling QP float separately from all other float. > We will still need to test if float is enabled at all so it won't help > all that much immediately, alas. > > With that TARGET_POWER10 condition fixed: okay for trunk, and for 11 > once it is tested for trunk on all systems. Thanks! Thanks. -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797