https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67085
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> --- The changes in r244150 turned some internal copies into moves, improving the PR 70898 testcase from 61 seconds to 29 seconds. If I modify the testcase attached here to track moves as well as copies, GCC 6 prints: Printing counts of numbers of calls to comparator copy + move constructors. Before queue construction: 0 + 0 After queue construction : 4 + 0 After 3 calls to push : 16 + 0 After 3 calls to pop : 33 + 0 Since r244150 GCC 7 trunk prints: Printing counts of numbers of calls to comparator copy + move constructors. Before queue construction: 0 + 0 After queue construction : 2 + 2 After 3 calls to push : 8 + 8 After 3 calls to pop : 17 + 16 I'm testing a patch that reduces the PR 70898 test to under 4s and makes the attachment here print: Printing counts of numbers of calls to comparator copy + move constructors. Before queue construction: 0 + 0 After queue construction : 1 + 3 After 3 calls to push : 4 + 12 After 3 calls to pop : 7 + 26 This doesn't help if your comparison function is only copyable and not movable, but it's 2017 not 2007 so I think that's OK.
