From: Patrick Palka <ppalka@redhat.com>
To: Jonathan Wakely <jwakely@redhat.com>
Cc: gcc Patches <gcc-patches@gcc.gnu.org>,
"libstdc++" <libstdc++@gcc.gnu.org>
Subject: Re: [PATCH 4/6] libstdc++: Adjust fast_float's over/underflow behavior for conformnace
Date: Mon, 17 Jan 2022 15:05:51 -0500 [thread overview]
Message-ID: <CAMOnLZYzzUBU61Mr-GnR_6P=vZMmTeb-Frm5J42s--bNcOM-aA@mail.gmail.com> (raw)
In-Reply-To: <CACb0b4=ewbVgjC02nz3xY1Ccn3s1d2=h6pEWE=JrdUYkTKgoxw@mail.gmail.com>
On Mon, Jan 17, 2022 at 5:49 AM Jonathan Wakely <jwakely@redhat.com> wrote:
>
>
>
> On Sun, 16 Jan 2022 at 18:12, Patrick Palka via Libstdc++ <libstdc++@gcc.gnu.org> wrote:
>>
>> This makes fast_float handle the situation where std::from_chars is
>> specified to return result_out_of_range, i.e. when the parsed value
>> is outside the representable range of the floating-point type.
>>
>> This adjusts fast_float's behavior in case of over/underflow: instead of
>> returning errc{} and setting value to +-0 or +-infinity, return
>> result_out_of_range and don't modify value, as per [charconv.from.chars]/1.
>>
>> libstdc++-v3/ChangeLog:
>>
>> * src/c++17/fast_float/LOCAL_PATCHES: Update.
>> * src/c++17/fast_float/fast_float.h (from_chars_advanced): In
>> case of over/underflow, return errc::result_out_of_range and don't
>> modify 'value'.
>>
>
> Typo in the commit summary line "conformnace".
>
> OK for trunk.
>
> Please report this as an issue to the upstream project, if you didn't already (and if they haven't documented this as an intentional deviation from the standard).
This behavior difference isn't documented AFAICT, so I reported the
issue upstream at https://github.com/fastfloat/fast_float/issues/120
next prev parent reply other threads:[~2022-01-17 20:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-16 18:06 [PATCH 1/6 v2] libstdc++: Directly implement hexfloat std::from_chars for binary32/64 Patrick Palka
2022-01-16 18:06 ` [PATCH 2/6] libstdc++: Import the fast_float library Patrick Palka
2022-01-17 10:45 ` Jonathan Wakely
2022-01-18 3:10 ` Hans-Peter Nilsson
2022-01-16 18:06 ` [PATCH 3/6] libstdc++: Apply modifications to our local copy of fast_float Patrick Palka
2022-01-17 10:46 ` Jonathan Wakely
2022-01-16 18:06 ` [PATCH 4/6] libstdc++: Adjust fast_float's over/underflow behavior for conformnace Patrick Palka
2022-01-17 10:49 ` Jonathan Wakely
2022-01-17 20:05 ` Patrick Palka [this message]
2022-01-16 18:06 ` [PATCH 5/6] libstdc++: Use fast_float in std::from_chars for binary32/64 Patrick Palka
2022-01-17 10:50 ` Jonathan Wakely
2022-01-16 18:06 ` [PATCH 6/6] libstdc++: Import MSVC floating-point std::from_chars testcases Patrick Palka
2022-01-17 10:54 ` Jonathan Wakely
2022-01-17 20:23 ` Patrick Palka
2022-01-17 10:34 ` [PATCH 1/6 v2] libstdc++: Directly implement hexfloat std::from_chars for binary32/64 Jonathan Wakely
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