http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49561
--- Comment #14 from Bryce Lelbach (wash) <blelbach at cct dot lsu.edu> 2012-07-03 03:35:31 UTC --- (In reply to comment #13) > Patch reverted, thus in C++11 mode size() is back to O(n) but std::list can > interoperate with the C++98 version of it. Why has this been reverted? If std::list<>::size() is not O(1), then GCC's C++11 standard library is not compliant with the C++11 international standard. I have personally spoken with multiple members of the standard body and confirmed that this behavior is REQUIRED by the C++11 standard. Please re-apply this patch for C++11 mode, or state somewhere in the GCC docs that GCC is not compliant with the C++11 standard. In the C++03 and C++98 standards, it was highly suggested that compiler vendors implement std::list<>::size() as O(1). I understand this is a breaking change, but honestly, the C++ standard has been suggesting the O(1) implementation for over a decade, and the GCC standard library developers have chosen to implement different behavior. You've had many years of warning about this. (In reply to comment #10) > I can confirm it was just luck, really. ^ Paolo, this is correct. I think it's a really, really bad idea for any particular vendor to cherrypick elements of an ISO standard to implement. If you feel that the C++11 standard is wrong to require an O(1) implementation, please file a standard defect (I'm afraid you can expect me to fight it). Otherwise, I'd like to ask that you please reconsider applying this patch.
