2016 LLVM Developers' Meeting - Bay Area

We want to discuss current state of libcxx performance w.r.t. libstdc++. What are the regressions that we know and plan to fix them. A few of the regressions are: 

PR21192 - Reading from stdin is 1-2 orders of magnitude slower than using libstdc++ 
PR19708 - std::find is significantly slower than libstdc++. 
PR20837 - libc++'s std::sort is O(N^2) in the worst case (instead of O(N*ln(N))). 
PR26886 - libc++'s std::stable_sort also has a worst-case complexity issue. 
PR15456 - A faster implementation of std::function is possible 
PR16747 and PR21275 - Our unordered_multimap insert is much slower than libstdc++'s 
- Removing Heap usage 
- Missing features (and performance issues) in <regex> 
- Non-conforming allocators in the test suite 
- Identifying missing attributes in functions 
- Debug mode for the library