Link-Time Optimization (LTO): The Next Level of Compiler Optimization?

This article explores Link-Time Optimization (LTO), a technique that enhances program performance by performing optimizations during the linking stage. Traditional compilers optimize within individual files, while LTO allows for more comprehensive cross-file optimizations, such as function inlining and improved code locality. While LTO can yield significant performance improvements (e.g., a 9.2% reduction in runtime and a 20% decrease in binary size in the ProjectX project test), it also requires longer compilation and linking times and more memory. The author compares experiments on ProjectX and ffmpeg to illustrate the advantages and disadvantages of LTO and suggests trying LTO on projects not aggressively optimized for speed, concluding that ultimate performance gains depend on the specific project.