libstdc++-v3/testsuite/20_util/assume_aligned/97132.cc

// Copyright (C) 2020-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
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// terms of the GNU General Public License as published by the
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// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
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// { dg-do compile { target c++20 } }

#include <memory>

// PR libstdc++/97132 - assume_aligned is not constexpr

constexpr bool test01()
{
  struct alignas(32) S { int i; };
  S s{42};
  int* p = std::assume_aligned<32>(&s.i);
  *p = 48;
  return s.i == 48;
}

static_assert( test01() );