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From: "wilco at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libgcc/108279] Improved speed for float128 routines
Date: Wed, 18 Jan 2023 20:10:47 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108279

--- Comment #21 from Wilco <wilco at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #20)
> __attribute__((noinline, optimize ("rounding-math"))) static int
> round_to_nearest (void) { return 1.0f - __FLT_MIN__ =3D=3D 1.0f + __FLT_M=
IN__; }

Wouldn't that always set inexact?

> and
>   if (round_to_nearest ()) \
>     _fcw =3D FP_RND_NEAREST; \
>   else \
>     __asm__ __volatile__ ("%vstmxcsr\t%0" : "=3Dm" (_fcw)); \
>=20
> Except that from _fcw we don't determine just the rounding mode but also
> what exceptions are enabled.

Yes that wouldn't work in fenv but FP emulation functions don't need to read
the exception flags.=