On Fri, 15 Oct 2021, Richard Biener via Gcc-patches wrote:
> On Fri, Sep 24, 2021 at 2:59 PM Jirui Wu via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > Hi,
> >
> > Ping: https://gcc.gnu.org/pipermail/gcc-patches/2021-August/577846.html
> >
> > The patch is attached as text for ease of use. Is there anything that needs
> > to change?
> >
> > Ok for master? If OK, can it be committed for me, I have no commit rights.
>
> I'm still not sure about the correctness. I suppose the
> flag_fp_int_builtin_inexact && !flag_trapping_math is supposed to guard
> against spurious inexact exceptions, shouldn't that be
> !flag_fp_int_builtin_inexact || !flag_trapping_math instead?
The following remarks may be relevant here, but are not intended as an
assertion of what is correct in this case.
1. flag_fp_int_builtin_inexact is the more permissive case ("inexact" may
or may not be raised). All existing uses in back ends are
"flag_fp_int_builtin_inexact || !flag_trapping_math" or equivalent.
2. flag_fp_int_builtin_inexact only applies to certain built-in functions
(as listed in invoke.texi). It's always unspecified, even in C2X, whether
casts of non-integer values from floating-point to integer types raise
"inexact". So flag_fp_int_builtin_inexact should not be checked in insn
patterns corresponding to simple casts from floating-point to integer,
only in insn patterns corresponding to the built-in functions listed for
-fno-fp-int-builtin-inexact in invoke.texi (or for operations that combine
such a built-in function with a cast of the *result* to integer type).
--
Joseph S. Myers
jos...@codesourcery.com
