From: Jonathan Wakely <jwakely@redhat.com>
To: Matthias Kretz <m.kretz@gsi.de>
Cc: gcc Patches <gcc-patches@gcc.gnu.org>,
"libstdc++" <libstdc++@gcc.gnu.org>
Subject: Re: [PATCH 04/11 v3] libstdc++: Make use of __builtin_bit_cast
Date: Fri, 25 Jun 2021 12:23:46 +0100 [thread overview]
Message-ID: <CACb0b4=x=_4okOWnydfNXp=QS5torF+-fN5Ct7gbu1X7BHzyDg@mail.gmail.com> (raw)
In-Reply-To: <14392010.RDIVbhacDa@minbar>
On Thu, 24 Jun 2021 at 15:02, Matthias Kretz wrote:
>
> For -ffast-math there was a missing using namespace __proposed left. The
> attached patch resolves the issue.
OK for trunk, please push (after adding yourself to the "Write After
Approval" section of MAINTAINERS as per
https://gcc.gnu.org/gitwrite.html as your first commit).
Thanks!
> From: Matthias Kretz <m.kretz@gsi.de>
>
> The __bit_cast function was a hack to achieve what __builtin_bit_cast
> can do, therefore use __builtin_bit_cast if possible. However,
> __builtin_bit_cast cannot be used to cast from/to fixed_size_simd, since
> it isn't trivially copyable (in the language sense — in principle it
> is). Therefore add __proposed::simd_bit_cast to enable the use case
> required in the test framework.
>
> Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
>
> libstdc++-v3/ChangeLog:
>
> * include/experimental/bits/simd.h (__bit_cast): Implement via
> __builtin_bit_cast #if available.
> (__proposed::simd_bit_cast): Add overloads for simd and
> simd_mask, which use __builtin_bit_cast (or __bit_cast #if not
> available), which return an object of the requested type with
> the same bits as the argument.
> * include/experimental/bits/simd_math.h: Use simd_bit_cast
> instead of __bit_cast to allow casts to fixed_size_simd.
> (copysign): Remove branch that was only required if __bit_cast
> cannot be constexpr.
> * testsuite/experimental/simd/tests/bits/test_values.h: Switch
> from __bit_cast to __proposed::simd_bit_cast since the former
> will not cast fixed_size objects anymore.
> ---
> libstdc++-v3/include/experimental/bits/simd.h | 57 ++++++++++++++++++-
> .../include/experimental/bits/simd_math.h | 37 ++++++------
> .../simd/tests/bits/test_values.h | 8 +--
> 3 files changed, 76 insertions(+), 26 deletions(-)
>
>
> --
> ──────────────────────────────────────────────────────────────────────────
> Dr. Matthias Kretz https://mattkretz.github.io
> GSI Helmholtz Centre for Heavy Ion Research https://gsi.de
> std::experimental::simd https://github.com/VcDevel/std-simd
> ──────────────────────────────────────────────────────────────────────────
next prev parent reply other threads:[~2021-06-25 11:24 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-08 12:10 [PATCH 00/11] stdx::simd optimizations, corrections, and cleanups Matthias Kretz
2021-06-08 12:11 ` [PATCH 01/11] libstdc++: Improve copysign codegen Matthias Kretz
2021-06-08 12:11 ` [PATCH 02/11] libstdc++: Remove dead code Matthias Kretz
2021-06-08 12:11 ` [PATCH 03/11] libstdc++: Improve fixed_size codegen Matthias Kretz
2021-06-08 12:11 ` [PATCH 04/11] libstdc++: Make use of __builtin_bit_cast Matthias Kretz
2021-06-11 10:53 ` [PATCH 04/11 v2] " Matthias Kretz
2021-06-24 14:01 ` [PATCH 04/11 v3] " Matthias Kretz
2021-06-24 14:08 ` Jakub Jelinek
2021-06-24 14:11 ` Jonathan Wakely
2021-06-24 14:12 ` Jonathan Wakely
2021-06-24 14:21 ` Jakub Jelinek
2021-06-24 14:34 ` Jonathan Wakely
2021-06-24 14:40 ` Jonathan Wakely
2021-06-24 14:44 ` Jakub Jelinek
2021-06-25 11:23 ` Jonathan Wakely [this message]
2021-06-08 12:11 ` [PATCH 05/11] libstdc++: Remove incorrect fabs overload Matthias Kretz
2021-06-08 12:11 ` [PATCH 06/11] libstdc++: Minor simd_math cleanups Matthias Kretz
2021-06-08 12:11 ` [PATCH 07/11] libstdc++: Fix condition when AVX512F ldexp implementation is used Matthias Kretz
2021-06-08 12:11 ` [PATCH 08/11] libstdc++: Avoid raising fp exceptions in trunc, floor, and ceil Matthias Kretz
2021-06-08 12:11 ` [PATCH 09/11] libstdc++: Ensure unrolled loops inline the lambda Matthias Kretz
2021-06-08 12:12 ` [PATCH 10/11] libstdc++: Fix internal names: add missing underscores Matthias Kretz
2021-06-08 12:12 ` [PATCH 11/11] libstdc++: Fix ODR issues with different -m flags Matthias Kretz
2021-06-09 12:22 ` Richard Biener
2021-06-09 12:53 ` Matthias Kretz
2021-06-09 13:22 ` Richard Biener
2021-11-15 8:57 ` Matthias Kretz
2022-01-14 21:30 ` Jonathan Wakely
2022-01-17 0:08 ` Jonathan Wakely
2021-06-24 13:42 ` [PATCH 00/11] stdx::simd optimizations, corrections, and cleanups Jonathan Wakely
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