From: Patrick Palka <ppalka@redhat.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Patrick Palka <ppalka@redhat.com>,
Jonathan Wakely <jwakely@redhat.com>,
Jonathan Wakely via Libstdc++ <libstdc++@gcc.gnu.org>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH 3/4] libstdc++: Add floating-point std::to_chars implementation
Date: Mon, 21 Dec 2020 12:06:58 -0500 (EST) [thread overview]
Message-ID: <b4135452-06e-683-fc51-2f781eca8a78@idea> (raw)
In-Reply-To: <alpine.LFD.2.21.2012202126141.1637534@eddie.linux-mips.org>
On Sun, 20 Dec 2020, Maciej W. Rozycki wrote:
> On Thu, 17 Dec 2020, Patrick Palka via Gcc-patches wrote:
>
> > > >libstdc++-v3/ChangeLog:
> > > >
> > > > * config/abi/pre/gnu.ver: Add new exports.
> > > > * include/std/charconv (to_chars): Declare the floating-point
> > > > overloads for float, double and long double.
> > > > * src/c++17/Makefile.am (sources): Add floating_to_chars.cc.
> > > > * src/c++17/Makefile.in: Regenerate.
> > > > * src/c++17/floating_to_chars.cc: New file.
> > > > (to_chars): Define for float, double and long double.
> > > > * testsuite/20_util/to_chars/long_double.cc: New test.
> > >
> > > Sorry it took so long to review, this is OK for trunk.
> > >
> > > The patch needs some minor changes to rebase it on the current trunk:
> > > The linker script has additions since you send this patch, so the
> > > context in the patch is wrong and it doesn't apply, and in <charconv>
> > > the first line of context in the patch needs to have 'noexcept' added.
> > > That rebase should be easy though.
> > >
> > > I'll look at adding __float128 support for powerpc64le.
> >
> > Thanks a lot. I committed the patch series just now, after rebasing
> > and retesting on x86_64, aarch64 and ppc64le.
>
> This breaks with the `vax-netbsdelf' target in GCC compilation:
>
> .../libstdc++-v3/src/c++17/floating_to_chars.cc:126:38: error: static assertion failed
> 126 | static_assert(__DBL_MANT_DIG__ == 53);
> | ^
> make[5]: *** [Makefile:577: floating_to_chars.lo] Error 1
>
> So what's the fallback/alternative for non-IEEE-754 FP targets? Shouldn't
> we call into libc (possibly with a warning attribute) for the formats we
> don't have explicit handcoded support for?
Sorry about this bootstrap breakage. For now, we should probably just
disable the entire file/implementation on such targets until a proper
fallback could be implemented. I posted a patch to that effect here
https://gcc.gnu.org/pipermail/gcc-patches/2020-December/562379.html
which is pending review/approval. Until then, manually stubbing out all of
floating_to_chars.cc should probably suffice to restore bootstrap on
this target.
next prev parent reply other threads:[~2020-12-21 17:07 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 19:41 [PATCH 1/4] libstdc++: Import parts of the Ryu library Patrick Palka
2020-07-14 19:41 ` [PATCH 2/4] libstdc++: Apply modifications to our local copy of Ryu Patrick Palka
2020-07-15 18:12 ` Patrick Palka
2020-12-17 14:35 ` Jonathan Wakely
2020-07-14 19:41 ` [PATCH 3/4] libstdc++: Add floating-point std::to_chars implementation Patrick Palka
2020-07-15 18:21 ` Patrick Palka
2020-07-17 4:23 ` Patrick Palka
2020-07-17 16:24 ` Patrick Palka
2020-07-20 3:37 ` Patrick Palka
2020-07-20 12:31 ` Jonathan Wakely
2020-07-20 12:53 ` Patrick Palka
2020-07-20 14:13 ` Jonathan Wakely
2020-07-20 14:46 ` Patrick Palka
2020-07-22 15:56 ` Patrick Palka
2020-08-19 21:57 ` Patrick Palka
2020-12-17 14:32 ` Jonathan Wakely
2020-12-18 4:13 ` Patrick Palka
2020-12-18 13:24 ` Christophe Lyon
2020-12-18 14:58 ` Jonathan Wakely
2020-12-18 15:00 ` Patrick Palka
2020-12-18 16:52 ` Christophe Lyon
2020-12-18 17:03 ` Patrick Palka
2020-12-18 18:28 ` Christophe Lyon
2020-12-20 21:44 ` Maciej W. Rozycki
2020-12-21 17:06 ` Patrick Palka [this message]
2020-12-21 23:09 ` Maciej W. Rozycki
2020-07-14 19:41 ` [PATCH 4/4] libstdc++: Import MSVC floating-point std::to_chars testcases Patrick Palka
2020-07-14 19:49 ` Patrick Palka
2020-12-17 14:37 ` Jonathan Wakely
2020-07-14 19:46 ` [PATCH 1/4] libstdc++: Import parts of the Ryu library Patrick Palka
2020-07-25 11:44 ` Václav Haisman
2020-07-26 13:09 ` Patrick Palka
2020-12-17 14:34 ` Jonathan Wakely
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