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From: "lee.imple at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/114417] std::experimental::simd is not a POD (by ABI definitions) and is always passed by reference instead of by value
Date: Thu, 21 Mar 2024 18:01:34 +0000	[thread overview]
Message-ID: <bug-114417-4-gQECOWgQCj@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114417-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114417

--- Comment #7 from Imple Lee <lee.imple at gmail dot com> ---
I tried to dig into the source code and it seems like it was designed to be
"passed via the stack". Not sure whether this was specified by the
specification (did not find relevant requirements, but I am not quite familiar
with that) or just an implementation choice.

In GCC git tree [libstdc++-v3/include/experimental/bits/simd_fixed_size.h, line
27](https://gcc.gnu.org/git?p=gcc.git;a=blob;f=libstdc%2B%2B-v3/include/experimental/bits/simd_fixed_size.h;h=408855212979cc32699db0805079ac74f495a8fa;hb=HEAD#l27):

...
  * The fixed_size ABI gives the following guarantees:
  *  - simd objects are passed via the stack
...

  parent reply	other threads:[~2024-03-21 18:01 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-21 16:05 [Bug libstdc++/114417] New: simd parameters are passed by memory on x64 , not using the available sse registers lee.imple at gmail dot com
2024-03-21 16:09 ` [Bug target/114417] " pinskia at gcc dot gnu.org
2024-03-21 16:16 ` lee.imple at gmail dot com
2024-03-21 16:17 ` lee.imple at gmail dot com
2024-03-21 16:26 ` [Bug target/114417] std::experimental::simd " pinskia at gcc dot gnu.org
2024-03-21 16:28 ` pinskia at gcc dot gnu.org
2024-03-21 16:34 ` [Bug libstdc++/114417] std::experimental::simd is not a POD (by ABI definitions) and is always passed by reference instead of by value pinskia at gcc dot gnu.org
2024-03-21 16:37 ` pinskia at gcc dot gnu.org
2024-03-21 18:01 ` lee.imple at gmail dot com [this message]
2024-03-22  1:37 ` de34 at live dot cn
2024-04-22 12:46 ` mkretz at gcc dot gnu.org
2024-04-22 12:48 ` mkretz at gcc dot gnu.org
2024-04-22 17:18 ` lee.imple at gmail dot com

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