Fix __gnu_cxx::throw_allocator 2 * O(log(N)) complexity

[Jonathan Wakely]

On 13/11/18 07:15 +0100, François Dumont wrote:
>Oops, it was not the tested patch. Here it is.
>
>On 11/12/18 7:43 AM, François Dumont wrote:
>>When doing some debugging session I noticed that the 
>>__gnu_cxx::throw_allocator doubles all lookup on both insert and 
>>erase.
>>
>>Using map::insert result and erasing the found iterator avoids this 
>>double lookup.
>>
>>Â Â Â  * include/ext/throw_allocator.h
>>Â Â Â  (annotate_base::insert(void*, size_t)): Use insert result to 
>>check for
>>Â Â Â  double insert attempt.
>>Â Â Â  (annotate_base::insert_construct(void*)): Likewise.
>>Â Â Â  (annotate_base::check_allocated(void*, size_t)): Return found 
>>iterator.
>>Â Â Â  (annotate_base::erase(void*, size_t)): Use latter method returned
>>Â Â Â  iterator.
>>Â Â Â  (annotate_base::check_constructed(void*, size_t)): Return found 
>>iterator.
>>Â Â Â  (annotate_base::erase_construct(void*)): Use latter method returned
>>Â Â Â  iterator.
>>
>>Tested under linux x86_64.
>>
>>Ok to commit ?

OK, thanks.