On Sun, 30 Jul 2023, Uros Bizjak wrote:
> Also introduce -m[no-]mmxfp-with-sse option to disable trapping V2SF
> named patterns in order to avoid generation of partial vector V4SFmode
> trapping instructions.
>
> The new option is enabled by default, because even with sanitization,
> a small but consistent speed up of 2 to 3% with Polyhedron capacita
> benchmark can be achieved vs. scalar code.
>
> Using -fno-trapping-math improves Polyhedron capacita runtime 8 to 9%
> vs. scalar code. This is what clang does by default, as it defaults
> to -fno-trapping-math.
I like the new option, note you lack invoke.texi documentation where
I'd also elaborate a bit on the interaction with -fno-trapping-math
and the possible performance impact then NaNs or denormals leak
into the upper halves and cross-reference -mdaz-ftz.
Thanks,
Richard.
> PR target/110832
>
> gcc/ChangeLog:
>
> * config/i386/i386.h (TARGET_MMXFP_WITH_SSE): New macro.
> * config/i386/i386/opt (mmmxfp-with-sse): New option.
> * config/i386/mmx.md (movq_<mode>_to_sse): Do not sanitize
> upper part of V2SFmode register with -fno-trapping-math.
> (<plusminusmult:insn>v2sf3): Enable for TARGET_MMXFP_WITH_SSE.
> (divv2sf3): Ditto.
> (<smaxmin:code>v2sf3): Ditto.
> (sqrtv2sf2): Ditto.
> (*mmx_haddv2sf3_low): Ditto.
> (*mmx_hsubv2sf3_low): Ditto.
> (vec_addsubv2sf3): Ditto.
> (vec_cmpv2sfv2si): Ditto.
> (vcond<V2FI:mode>v2sf): Ditto.
> (fmav2sf4): Ditto.
> (fmsv2sf4): Ditto.
> (fnmav2sf4): Ditto.
> (fnmsv2sf4): Ditto.
> (fix_truncv2sfv2si2): Ditto.
> (fixuns_truncv2sfv2si2): Ditto.
> (floatv2siv2sf2): Ditto.
> (floatunsv2siv2sf2): Ditto.
> (nearbyintv2sf2): Ditto.
> (rintv2sf2): Ditto.
> (lrintv2sfv2si2): Ditto.
> (ceilv2sf2): Ditto.
> (lceilv2sfv2si2): Ditto.
> (floorv2sf2): Ditto.
> (lfloorv2sfv2si2): Ditto.
> (btruncv2sf2): Ditto.
> (roundv2sf2): Ditto.
> (lroundv2sfv2si2): Ditto.
>
> Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
>
> Uros.
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
