Taking another swing at correctly optimizing fill_n.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@187587 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/algorithm b/include/algorithm
index 119fbbb..1403fd6 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -1987,17 +1987,23 @@
template <class _OutputIterator, class _Size, class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
-__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_, false_type)
+__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
{
for (; __n > 0; ++__first, --__n)
*__first = __value_;
return __first;
}
-template <class _OutputIterator, class _Size, class _Tp>
+template <class _Tp, class _Size, class _Up>
inline _LIBCPP_INLINE_VISIBILITY
-_OutputIterator
-__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_, true_type)
+typename enable_if
+<
+ is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
+ !is_same<_Tp, bool>::value &&
+ is_integral<_Up>::value && sizeof(_Up) == 1,
+ _Tp*
+>::type
+__fill_n(_Tp* __first, _Size __n,_Up __value_)
{
if (__n > 0)
_VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
@@ -2009,11 +2015,7 @@
_OutputIterator
fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
{
- return _VSTD::__fill_n(__first, __n, __value_, integral_constant<bool,
- is_pointer<_OutputIterator>::value &&
- is_trivially_assignable<typename remove_pointer<_OutputIterator>::type, _Tp>::value &&
- is_convertible<_Tp, unsigned char>::value &&
- sizeof(typename remove_pointer<_OutputIterator>::type) == 1>());
+ return _VSTD::__fill_n(__first, __n, __value_);
}
// fill
diff --git a/test/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp b/test/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
index 68bea69..bffcf1b 100644
--- a/test/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
+++ b/test/algorithms/alg.modifying.operations/alg.fill/fill_n.pass.cpp
@@ -94,6 +94,44 @@
assert(test1a[3].c == 11);
}
+class A
+{
+ char a_;
+public:
+ A() {}
+ explicit A(char a) : a_(a) {}
+ operator unsigned char() const {return 'b';}
+
+ friend bool operator==(const A& x, const A& y)
+ {return x.a_ == y.a_;}
+};
+
+void
+test5()
+{
+ A a[3];
+ assert(std::fill_n(&a[0], 3, A('a')) == a+3);
+ assert(a[0] == A('a'));
+ assert(a[1] == A('a'));
+ assert(a[2] == A('a'));
+}
+
+struct Storage
+{
+ union
+ {
+ unsigned char a;
+ unsigned char b;
+ };
+};
+
+void test6()
+{
+ Storage foo[5];
+ std::fill_n(&foo[0], 5, Storage());
+}
+
+
int main()
{
test_char<forward_iterator<char*> >();
@@ -109,4 +147,7 @@
test_int_array();
test_int_array_struct_source();
test_struct_array();
+
+ test5();
+ test6();
}