https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92300
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-10-31
Ever confirmed|0 |1
Severity|normal |enhancement
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
make_pair(1, 2) creates a std::pair<int, int> which is not the same type as the
value_type. That means there's a conversion from pair<int, int> to pair<const
int, int>, which gets done by allocating a node, constructing the value_type
into the node, then checking if the key exists. That's the expected behaviour
when inserting something that is not the same type as the value_type, so I
don't think this is a bug.
We could special-case pair<key_type, mapped_type> to avoid that step, because
we can use the non-const key directly. Converting it to a const key isn't
needed to check if it exists.
In fact we could special-case pair<cv key_type, anything>.
Confirming as an enhancement request.
