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D48342.diff
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Created
Thu, Jun 20, 4:07 PM

D48342.diff

Index: libcxx/trunk/include/memory
===================================================================
--- libcxx/trunk/include/memory
+++ libcxx/trunk/include/memory
@@ -1502,6 +1502,12 @@
typedef typename _Alloc::difference_type type;
};
+template <class _Tp>
+struct __is_default_allocator : false_type {};
+
+template <class _Tp>
+struct __is_default_allocator<_VSTD::allocator<_Tp> > : true_type {};
+
template <class _Alloc>
struct _LIBCPP_TEMPLATE_VIS allocator_traits
{
@@ -1615,7 +1621,7 @@
static
typename enable_if
<
- (is_same<allocator_type, allocator<_Tp> >::value
+ (__is_default_allocator<allocator_type>::value
|| !__has_construct<allocator_type, _Tp*, _Tp>::value) &&
is_trivially_move_constructible<_Tp>::value,
void
@@ -1640,23 +1646,25 @@
construct(__a, _VSTD::__to_raw_pointer(__begin2), *__begin1);
}
- template <class _Tp>
+ template <class _SourceTp, class _DestTp,
+ class _RawSourceTp = typename remove_const<_SourceTp>::type,
+ class _RawDestTp = typename remove_const<_DestTp>::type>
_LIBCPP_INLINE_VISIBILITY
static
typename enable_if
<
- (is_same<allocator_type, allocator<_Tp> >::value
- || !__has_construct<allocator_type, _Tp*, _Tp>::value) &&
- is_trivially_move_constructible<_Tp>::value,
+ is_trivially_move_constructible<_DestTp>::value &&
+ is_same<_RawSourceTp, _RawDestTp>::value &&
+ (__is_default_allocator<allocator_type>::value ||
+ !__has_construct<allocator_type, _DestTp*, _SourceTp&>::value),
void
>::type
- __construct_range_forward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
+ __construct_range_forward(allocator_type&, _SourceTp* __begin1, _SourceTp* __end1, _DestTp*& __begin2)
{
- typedef typename remove_const<_Tp>::type _Vp;
ptrdiff_t _Np = __end1 - __begin1;
if (_Np > 0)
{
- _VSTD::memcpy(const_cast<_Vp*>(__begin2), __begin1, _Np * sizeof(_Tp));
+ _VSTD::memcpy(const_cast<_RawDestTp*>(__begin2), __begin1, _Np * sizeof(_DestTp));
__begin2 += _Np;
}
}
@@ -1679,7 +1687,7 @@
static
typename enable_if
<
- (is_same<allocator_type, allocator<_Tp> >::value
+ (__is_default_allocator<allocator_type>::value
|| !__has_construct<allocator_type, _Tp*, _Tp>::value) &&
is_trivially_move_constructible<_Tp>::value,
void
Index: libcxx/trunk/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
===================================================================
--- libcxx/trunk/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
+++ libcxx/trunk/test/std/containers/sequences/vector/vector.cons/construct_iter_iter.pass.cpp
@@ -146,9 +146,40 @@
#endif
}
+// Initialize a vector with a different value type.
+void test_ctor_with_different_value_type() {
+ {
+ // Make sure initialization is performed with each element value, not with
+ // a memory blob.
+ float array[3] = {0.0f, 1.0f, 2.0f};
+ std::vector<int> v(array, array + 3);
+ assert(v[0] == 0);
+ assert(v[1] == 1);
+ assert(v[2] == 2);
+ }
+ struct X { int x; };
+ struct Y { int y; };
+ struct Z : X, Y { int z; };
+ {
+ Z z;
+ Z *array[1] = { &z };
+ // Though the types Z* and Y* are very similar, initialization still cannot
+ // be done with `memcpy`.
+ std::vector<Y*> v(array, array + 1);
+ assert(v[0] == &z);
+ }
+ {
+ // Though the types are different, initialization can be done with `memcpy`.
+ int32_t array[1] = { -1 };
+ std::vector<uint32_t> v(array, array + 1);
+ assert(v[0] == 4294967295);
+ }
+}
+
int main() {
basic_test_cases();
emplaceable_concept_tests(); // See PR34898
test_ctor_under_alloc();
+ test_ctor_with_different_value_type();
}

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