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From: "hubicka at ucw dot cz" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/109849] suboptimal code for vector walking loop
Date: Wed, 29 Nov 2023 12:27:02 +0000 [thread overview]
Message-ID: <bug-109849-4-67SxXLrEEr@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109849-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109849
--- Comment #32 from Jan Hubicka <hubicka at ucw dot cz> ---
> /tmp/build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_algobase.h:437:
> warning: 'void* __builtin_memcpy(void*, const void*, long unsigned int)'
> writing between 2 and 9223372036854775806 bytes into a region of size 0
> overflows the destination [-Wstringop-overflow=]
It warns on:
template<bool _IsMove>
struct __copy_move<_IsMove, true, random_access_iterator_tag>
{
template<typename _Tp, typename _Up>
_GLIBCXX20_CONSTEXPR
static _Up*
__copy_m(_Tp* __first, _Tp* __last, _Up* __result)
{
const ptrdiff_t _Num = __last - __first;
if (__builtin_expect(_Num > 1, true))
__builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
else if (_Num == 1)
std::__copy_move<_IsMove, false, random_access_iterator_tag>::
__assign_one(__result, __first);
return __result + _Num;
}
};
It is likely false positive on a code path that never happens in real
code, but we now optimize it better.
Does it show an inline path?
next prev parent reply other threads:[~2023-11-29 12:27 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-13 22:26 [Bug middle-end/109849] New: " hubicka at gcc dot gnu.org
2023-05-13 22:32 ` [Bug middle-end/109849] " pinskia at gcc dot gnu.org
2023-05-13 22:40 ` pinskia at gcc dot gnu.org
2023-05-14 5:57 ` amonakov at gcc dot gnu.org
2023-05-14 9:58 ` hubicka at ucw dot cz
2023-05-14 10:01 ` hubicka at ucw dot cz
2023-05-15 6:56 ` rguenth at gcc dot gnu.org
2023-05-17 14:53 ` hubicka at gcc dot gnu.org
2023-05-17 20:36 ` rguenth at gcc dot gnu.org
2023-05-18 9:35 ` hubicka at gcc dot gnu.org
2023-05-18 11:54 ` rguenth at gcc dot gnu.org
2023-05-18 13:00 ` hubicka at gcc dot gnu.org
2023-05-23 9:57 ` cvs-commit at gcc dot gnu.org
2023-05-23 10:10 ` rguenth at gcc dot gnu.org
2023-05-24 11:19 ` cvs-commit at gcc dot gnu.org
2023-06-16 14:20 ` hubicka at gcc dot gnu.org
2023-06-18 16:59 ` cvs-commit at gcc dot gnu.org
2023-06-19 16:28 ` cvs-commit at gcc dot gnu.org
2023-06-26 16:30 ` cvs-commit at gcc dot gnu.org
2023-06-28 9:47 ` cvs-commit at gcc dot gnu.org
2023-06-29 20:46 ` cvs-commit at gcc dot gnu.org
2023-06-30 14:28 ` cvs-commit at gcc dot gnu.org
2023-11-19 15:25 ` hubicka at gcc dot gnu.org
2023-11-21 14:17 ` cvs-commit at gcc dot gnu.org
2023-11-21 15:12 ` hubicka at gcc dot gnu.org
2023-11-24 16:35 ` cvs-commit at gcc dot gnu.org
2023-11-24 17:00 ` cvs-commit at gcc dot gnu.org
2023-11-24 17:00 ` jamborm at gcc dot gnu.org
2023-11-27 14:39 ` rguenth at gcc dot gnu.org
2023-11-28 9:33 ` redi at gcc dot gnu.org
2023-11-28 10:32 ` jamborm at gcc dot gnu.org
2023-11-28 12:41 ` redi at gcc dot gnu.org
2023-11-28 13:29 ` redi at gcc dot gnu.org
2023-11-28 15:29 ` redi at gcc dot gnu.org
2023-11-28 22:21 ` redi at gcc dot gnu.org
2023-11-29 12:27 ` hubicka at ucw dot cz [this message]
2023-11-29 15:25 ` cvs-commit at gcc dot gnu.org
2024-01-03 17:41 ` jamborm at gcc dot gnu.org
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