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<vector>: Avoid off-by-default warning C4365 in vector<bool> copy algorithms with /J #6013

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<vector>: Avoid off-by-default warning C4365 in vector<bool> copy algorithms with /J #6013

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655e813
Avoid off-by-default warning C4365 when assigning promoted `int` to `…
StephanTLavavej Jan 14, 2026
e11fb95
Add test coverage for squirrelly `/J` to `GH_000625_vector_bool_optim…
StephanTLavavej Jan 14, 2026
3fa037b
Fix off-by-default warning C4365 in `GH_000625_vector_bool_optimizati…
StephanTLavavej Jan 14, 2026
6b4b4ce
Merge branch 'main' into vector-bool-warnings
StephanTLavavej Jan 15, 2026
fd2143e
All shall love unsigned char and despair.
StephanTLavavej Jan 15, 2026
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29 changes: 16 additions & 13 deletions stl/inc/vector
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Original file line number Diff line number Diff line change
Expand Up @@ -3704,8 +3704,8 @@ _CONSTEXPR20 void _Fill_vbool(_VbIt _First, const _VbIt _Last, const bool _Val)
} else
#endif // _HAS_CXX20
{
const auto _VbFirst_ch = reinterpret_cast<const char*>(_VbFirst);
const auto _VbLast_ch = reinterpret_cast<const char*>(_VbLast);
const auto _VbFirst_ch = reinterpret_cast<const unsigned char*>(_VbFirst);
const auto _VbLast_ch = reinterpret_cast<const unsigned char*>(_VbLast);
const auto _Count_ch = static_cast<size_t>(_VbLast_ch - _VbFirst_ch);
const auto _ValChar = static_cast<unsigned char>(_Val ? -1 : 0);
_CSTD memset(_VbFirst, _ValChar, _Count_ch);
Expand Down Expand Up @@ -3894,21 +3894,24 @@ _CONSTEXPR20 _OutIt _Copy_vbool(_VbIt _First, _VbIt _Last, _OutIt _Dest) {
} else
#endif // _HAS_CXX20
{
// If _First and _Dest have matching char alignment, use memmove
// If _First and _Dest have matching unsigned char alignment, use memmove
const auto _UnalignedFirstBits = _First._Myoff & _Vbase{7};
const auto _UnalignedDestBits = _Dest._Myoff & _Vbase{7};
if (_UnalignedFirstBits == _UnalignedDestBits) {
const auto _UnalignedLastBits = _Last._Myoff & _Vbase{7};

auto _VbFirst_ch = reinterpret_cast<const char*>(_VbFirst) + (_First._Myoff - _UnalignedFirstBits) / 8;
const auto _VbLast_ch = reinterpret_cast<const char*>(_VbLast) + (_Last._Myoff - _UnalignedLastBits) / 8;
auto _VbDest_ch = reinterpret_cast<char*>(_VbDest) + (_Dest._Myoff - _UnalignedDestBits) / 8;
auto _VbFirst_ch =
reinterpret_cast<const unsigned char*>(_VbFirst) + (_First._Myoff - _UnalignedFirstBits) / 8;
const auto _VbLast_ch =
reinterpret_cast<const unsigned char*>(_VbLast) + (_Last._Myoff - _UnalignedLastBits) / 8;
auto _VbDest_ch = reinterpret_cast<unsigned char*>(_VbDest) + (_Dest._Myoff - _UnalignedDestBits) / 8;

// Copy bits until the next char alignment
// Copy bits until the next unsigned char alignment
if (_UnalignedFirstBits != 0) {
const auto _SourceBitMask = static_cast<char>(UCHAR_MAX << _UnalignedFirstBits);
const auto _DestBitMask = static_cast<char>(UCHAR_MAX >> (8 - _UnalignedFirstBits));
*_VbDest_ch = (*_VbDest_ch & _DestBitMask) | (*_VbFirst_ch & _SourceBitMask);
const auto _SourceBitMask = static_cast<unsigned char>(UCHAR_MAX << _UnalignedFirstBits);
const auto _DestBitMask = static_cast<unsigned char>(UCHAR_MAX >> (8 - _UnalignedFirstBits));
*_VbDest_ch =
static_cast<unsigned char>((*_VbDest_ch & _DestBitMask) | (*_VbFirst_ch & _SourceBitMask));
++_VbFirst_ch;
++_VbDest_ch;
}
Expand All @@ -3917,9 +3920,9 @@ _CONSTEXPR20 _OutIt _Copy_vbool(_VbIt _First, _VbIt _Last, _OutIt _Dest) {

// Copy remaining last bits
if (_UnalignedLastBits != 0) {
const auto _SourceBitMask = static_cast<char>(UCHAR_MAX >> (8 - _UnalignedLastBits));
const auto _DestBitMask = static_cast<char>(UCHAR_MAX << _UnalignedLastBits);
*_VbDest_ch = (*_VbDest_ch & _DestBitMask) | (*_VbLast_ch & _SourceBitMask);
const auto _SourceBitMask = static_cast<unsigned char>(UCHAR_MAX >> (8 - _UnalignedLastBits));
const auto _DestBitMask = static_cast<unsigned char>(UCHAR_MAX << _UnalignedLastBits);
*_VbDest_ch = static_cast<unsigned char>((*_VbDest_ch & _DestBitMask) | (*_VbLast_ch & _SourceBitMask));
}

return _DestEnd;
Expand Down
3 changes: 3 additions & 0 deletions tests/std/tests/GH_000625_vector_bool_optimization/env.lst
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Original file line number Diff line number Diff line change
Expand Up @@ -2,3 +2,6 @@
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

RUNALL_INCLUDE ..\usual_matrix.lst
RUNALL_CROSSLIST
* PM_CL=""
* PM_CL="/J"
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