On 08/05/19 18:50 +0200, François Dumont wrote:
Here is a patch to reduce number of operators exposed at std namespace
scope.
* include/bits/stl_deque.h
(_Deque_iterator<>::operator+(difference_type)): Make hidden friend.
(_Deque_iterator<>::operator-(difference_type)): Likewise.
(operator==(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
(operator!=(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
(operator<(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
(operator<=(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
(operator>(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
(operator>=(const _Deque_iterator<>&, const _Deque_iterator<>&)):
Likewise.
Tested under Linux x86_64 normal/debug modes.
Ok to commit ?
François
diff --git a/libstdc++-v3/include/bits/stl_deque.h
b/libstdc++-v3/include/bits/stl_deque.h
index 7a7a42aa903..72420c27646 100644
--- a/libstdc++-v3/include/bits/stl_deque.h
+++ b/libstdc++-v3/include/bits/stl_deque.h
@@ -238,24 +238,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
return *this;
}
- _Self
- operator+(difference_type __n) const _GLIBCXX_NOEXCEPT
- {
- _Self __tmp = *this;
- return __tmp += __n;
- }
-
_Self&
operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
{ return *this += -__n; }
- _Self
- operator-(difference_type __n) const _GLIBCXX_NOEXCEPT
- {
- _Self __tmp = *this;
- return __tmp -= __n;
- }
-
These two are already not visible at namespace-scope, but it doesn't
hurt to make them hidden friends for consistency.
+ friend _Self
+ operator+(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
+ {
+ _Self __tmp = __x;
+ return __tmp += __n;
I know you've just reused the original implementation, but it has a
problem that we might as well fix while touching t his code.
This function prevents NRVO copy elision, because __tmp += __n returns
a reference, which gets copied into the return value.
If you write it like this then the copy is elided, and __tmp is
constructed directly in the return value slot:
_Self __tmp = __x;
__tmp += __n;
return __tmp;
+ friend _Self
+ operator-(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
+ {
+ _Self __tmp = __x;
+ return __tmp -= __n;
Same problem here. It would be better to write:
_Self __tmp = __x;
__tmp -= __n;
return __tmp;
OK for trunk with those two changes, thanks.
