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From: Richard Biener <richard.guenther@gmail.com>
To: Georg Johann Lay <avr@gjlay.de>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [patch, avr] Fix PR target/99184: Wrong cast from double to 16-bit and 32-bit ints.
Date: Mon, 19 Sep 2022 09:51:52 +0200	[thread overview]
Message-ID: <CAFiYyc0qsrXMq608-B7v+ZP-T60Nei18KMM+5bJax12dCyFH=A@mail.gmail.com> (raw)
In-Reply-To: <f4ae2f92-9ee2-ff9d-603a-d73c010a2fe3@gjlay.de>

On Sun, Sep 18, 2022 at 7:40 PM Georg Johann Lay <avr@gjlay.de> wrote:
>
> Hello,
>
> this patch fixed PR target/99184 which incorrectly rounded during 64-bit
> (long) double to 16-bit and 32-bit integers.
>
> The patch just removes the respective roundings from
> libf7-asm.sx::to_integer and ::to_unsigned.  Luckily, LibF7 does nowhere
> use respective functions internally, the only user is in libf7.c::f7_exp
>
> which reads
>
>    f7_round (qq, qq);
>    int16_t q = f7_get_s16 (qq);
>
> so that f7_get_s16() operates on an already rounded value, and therefore
> this code works unaltered with or without rounding in to_integer.
>
> The patch applies to directory
>
> ./libgcc/config/avr/libf7/
>
> and is the same for all GCC versions v10+.
>
> Please someone with write permissions commit it to trunk and backport to
> v12, v11, and v10 as it is a wrong-code issue.
>
> The patch will fit without problems (except for ChangeLog) because there
> is no traffic on that folder.

Thanks, I've pushed the change.  Please in future try to send patches
that can be applied with git am, thus use git format-patch

Richard.

>
> Thanks, Johann
>
>
> libgcc/config/avr/libf7/
>         PR target/99184
>         Remove rounding from double to [u]int16 and [u]int32 casts.
>
>         * libf7-asm.sx (to_integer, to_unsigned): Don't round 16-bit
>         and 32-bit integers.
>

  reply	other threads:[~2022-09-19  7:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-18 17:39 [patch,avr] " Georg Johann Lay
2022-09-19  7:51 ` Richard Biener [this message]
2022-09-19  8:57   ` [patch, avr] " Georg Johann Lay
2022-09-19  9:06     ` Richard Biener
2022-09-19 14:58       ` Jonathan Wakely

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