From: David Christensen <drc@linux.vnet.ibm.com>
To: David Marchand <david.marchand@redhat.com>,
Stanislaw Kardach <kda@semihalf.com>
Cc: dev <dev@dpdk.org>,
upstream@semihalf.com, Aaron Conole <aconole@redhat.com>,
Bruce Richardson <bruce.richardson@intel.com>,
"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
"Ruifeng Wang (Arm Technology China)" <ruifeng.wang@arm.com>,
Jerin Jacob Kollanukkaran <jerinj@marvell.com>
Subject: Re: [PATCH 0/3] Fix xmm_t to rte_xmm_t scalar conversion
Date: Mon, 20 Jun 2022 15:54:48 -0700 [thread overview]
Message-ID: <63ed6e6c-337d-8f8a-9410-1e43b0561967@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAJFAV8yDTyLG8hGR+X2x0Yp9g=L91ZuaxaseNbg=CpUBm7FoAQ@mail.gmail.com>
> On Thu, Jun 9, 2022 at 2:17 PM Stanislaw Kardach <kda@semihalf.com> wrote:
>>
>> As David noticed in [1] there is an issue with C++ compilation of the
>> rte_vect.h header in RISC-V. Upon closer inspection, the problem appears on
>> all architectures due to the type conversion rules in C++.
>> More precisely a union type rte_xmm_t requires a conversion constructor
>> from xmm_t type.
>> The most obvious fix is to use a structure initializer for such copies
>> (since rte_xmm_t union contains xmm_t anyway). The generated assembly
>> at -O2 is exactly the same, so there's no real impact.
>>
>> The bigger question is whether accessing bits of the architecture specific
>> xmm_t type in an array fashion is always correct? All current architectures
>> define rte_xmm_t in the same manner implying that.
>
> Copying other arch maintainers.
My read of the Altivec vector layout for LE systems says the existing
union operator rte_xmm_t is correct, though my C++ experience is
limited. How can I generate an error with C++ to expose this issue?
Dave
next prev parent reply other threads:[~2022-06-20 22:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-09 12:16 Stanislaw Kardach
2022-06-09 12:16 ` [PATCH 1/3] eal/riscv: fix xmm_t casting for C++ Stanislaw Kardach
2022-06-13 9:29 ` David Marchand
2022-06-09 12:17 ` [PATCH 2/3] lpm: fix xmm_t casting for C++ in scalar version Stanislaw Kardach
2022-06-13 9:29 ` David Marchand
2022-06-09 12:17 ` [PATCH 3/3] ci: use crossbuild-essential-riscv64 for compiling Stanislaw Kardach
2022-06-13 9:29 ` David Marchand
2022-06-14 12:31 ` Aaron Conole
2022-06-15 7:25 ` [PATCH 0/3] Fix xmm_t to rte_xmm_t scalar conversion David Marchand
2022-06-20 22:54 ` David Christensen [this message]
2022-06-21 9:30 ` Stanisław Kardach
2022-06-21 9:38 ` Bruce Richardson
2022-06-21 9:42 ` Stanisław Kardach
2022-06-21 9:49 ` Bruce Richardson
2022-06-21 10:22 ` Thomas Monjalon
2022-06-21 11:05 ` Stanisław Kardach
2022-06-21 11:53 ` Thomas Monjalon
2022-06-21 12:37 ` Stanisław Kardach
2022-06-21 14:20 ` Bruce Richardson
2022-06-21 19:48 ` Tyler Retzlaff
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=63ed6e6c-337d-8f8a-9410-1e43b0561967@linux.vnet.ibm.com \
--to=drc@linux.vnet.ibm.com \
--cc=aconole@redhat.com \
--cc=bruce.richardson@intel.com \
--cc=david.marchand@redhat.com \
--cc=dev@dpdk.org \
--cc=jerinj@marvell.com \
--cc=kda@semihalf.com \
--cc=konstantin.ananyev@intel.com \
--cc=ruifeng.wang@arm.com \
--cc=upstream@semihalf.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).