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From: "fchelnokov at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/114537] bit_cast does not work NSDMI of bitfields
Date: Mon, 01 Apr 2024 09:40:48 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114537

--- Comment #1 from Fedor Chelnokov <fchelnokov at gmail dot com> ---
Probably related:
```
#include <bit>

struct A { int a: 7; };

static_assert( 1 =3D=3D std::bit_cast<A>(std::bit_cast<int>(A{1})).a );
```
It looks valid and accepted by MSVC, but GCC prints:
error: '__builtin_bit_cast' accessing uninitialized byte at offset 0

Online demo: https://gcc.godbolt.org/z/3W5onY955=