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[deque] fix: constexpr support for deque in C++23 #1281

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[deque] fix: constexpr support for deque in C++23 #1281

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c38d330
[deque] fix: constexpr support for deque in C++26
SekaiArendelle Jun 14, 2026
ecb2474
guard __builtin_operator_new with FAST_IO_HAS_BUILTIN, fallback to ::…
SekaiArendelle Jun 14, 2026
abc9d0d
guard __builtin_operator_delete with FAST_IO_HAS_BUILTIN, fallback to…
SekaiArendelle Jun 14, 2026
3db5734
replace __builtin_is_constant_evaluated with #if __cpp_if_consteval /…
SekaiArendelle Jun 14, 2026
be31236
[deque][test] guard constexpr test with #if for GCC>=15 / clang>=22
SekaiArendelle Jun 14, 2026
44a1f6f
Am I forgot to submit something?
SekaiArendelle Jun 14, 2026
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64 changes: 54 additions & 10 deletions include/fast_io_core_impl/allocation/adapters.h
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
#pragma once
#pragma once

// To make a constexpr allocator, we need ::std::allocator. Because only new expression and
// ::std::allocator<T>::allocate are allowed in constexpr functions. See https://github.com/microsoft/STL/issues/1532
Expand Down Expand Up @@ -145,10 +145,16 @@ class generic_allocator_adapter
if (false)
#endif
{
auto p{::operator new(n)};
auto p{
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
};
if (zero)
{
::fast_io::freestanding::bytes_clear_n(reinterpret_cast<::std::byte *>(p), n);
::fast_io::freestanding::bytes_clear_n(static_cast<::std::byte *>(p), n);
}
return p;
}
Expand Down Expand Up @@ -682,7 +688,11 @@ class generic_allocator_adapter
#if __cpp_constexpr_dynamic_alloc >= 201907L
if (__builtin_is_constant_evaluated())
{
#if FAST_IO_HAS_BUILTIN(__builtin_operator_delete)
__builtin_operator_delete(p);
#else
::operator delete(p);
#endif
}
else
#endif
Expand All @@ -704,7 +714,11 @@ class generic_allocator_adapter
#if __cpp_constexpr_dynamic_alloc >= 201907L
if (__builtin_is_constant_evaluated())
{
#if FAST_IO_HAS_BUILTIN(__builtin_operator_delete)
__builtin_operator_delete(p);
#else
::operator delete(p);
#endif
}
else
#endif
Expand Down Expand Up @@ -747,10 +761,16 @@ class generic_allocator_adapter
if (false)
#endif
{
auto p{::operator new(n)};
auto p{
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
};
if (zero)
{
::fast_io::freestanding::bytes_clear_n(reinterpret_cast<::std::byte *>(p), n);
::fast_io::freestanding::bytes_clear_n(static_cast<::std::byte *>(p), n);
}
return p;
}
Expand Down Expand Up @@ -847,7 +867,13 @@ class generic_allocator_adapter
if (false)
#endif
{
return ::operator new(n);
return
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
;
}
if constexpr (::fast_io::details::has_allocate_aligned_impl<alloc>)
{
Expand All @@ -874,7 +900,13 @@ class generic_allocator_adapter
if (false)
#endif
{
return ::operator new(n);
return
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
;
}
if constexpr (::fast_io::details::has_allocate_aligned_zero_impl<alloc>)
{
Expand Down Expand Up @@ -904,7 +936,13 @@ class generic_allocator_adapter
if (false)
#endif
{
return {::operator new(n), n};
return {
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
, n};
}
else
{
Expand All @@ -931,7 +969,13 @@ class generic_allocator_adapter
if (false)
#endif
{
return {::operator new(n), n};
return {
#if FAST_IO_HAS_BUILTIN(__builtin_operator_new)
__builtin_operator_new(n)
#else
::operator new(n)
#endif
, n};
}
else
{
Expand Down Expand Up @@ -2062,7 +2106,7 @@ class generic_allocator_adapter
if (false)
#endif
{
return ::operator new(n);
return static_cast<void *>(::fast_io::freestanding::allocator<::std::byte>{}.allocate(n));
}
else
{
Expand Down
16 changes: 14 additions & 2 deletions include/fast_io_core_impl/freestanding/algorithm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -301,9 +301,21 @@ inline constexpr output_iter overlapped_copy_trivial(input_iter first, ::std::si
{
tempbufferptr[i] = first[i];
}
for (::std::size_t i{}; i != n; ++i)
#if __cpp_if_consteval >= 202106L
if consteval
{
for (::std::size_t i{}; i != n; ++i)
{
::std::construct_at(::std::addressof(result[i]), ::std::move(tempbufferptr[i]));
}
}
else
#endif
{
result[i] = ::std::move(tempbufferptr[i]);
for (::std::size_t i{}; i != n; ++i)
{
result[i] = ::std::move(tempbufferptr[i]);
}
}
return result + n;
}
Expand Down
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