[libc++] Speed up set_intersection() by fast-forwarding over ranges of non-matching elements with one-sided binary search. (#75230) One-sided binary search, aka meta binary search, has been in the public domain for decades, and has the general advantage of being constant time in the best case, with the downside of executing at most 2*log(N) comparisons vs classic binary search's exact log(N). There are two scenarios in which it really shines: the first one is when operating over non-random-access iterators, because the classic algorithm requires knowing the container's size upfront, which adds N iterator increments to the complexity. The second one is when traversing the container in order, trying to fast-forward to the next value: in that case the classic algorithm requires at least O(N*log(N)) comparisons and, for non-random-access iterators, O(N^2) iterator increments, whereas the one-sided version will yield O(N) operations on both counts, with a best-case of O(log(N)) comparisons which is very common in practice.
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.