Fedora 47 Considering Use Of Thin LTO Compiler Optimizations

A change proposal filed for what would be part of Fedora Linux 47 is on making use of Thin LTO rather than Fat LTO for link-time optimizations. With Thin LTO being more memory efficient and faster build speeds, the hope is that more Fedora packages could also use Thin LTO for packages where no link-time optimizations are currently leveraged. Thin LTO "ThinLTO" is quicker and more memory efficient than traditional "fat" link-time optimizations by compilers. Thin LTO is typically more scalable while keeping much of the performance benefits of the full LTO mode and can be activated with the -flto=thin compiler flag. With the change proposal a new RPM macro would be introduced to enable LTO with thin objects to ease in its adoption. The change doesn't mandate the use of any LTO by packages but that would be a later potential system-wide change proposal. From this initial proposal, Fedora packagers could decide to add ThinLTO to their existing packages or evaluate the build time improvement and performance if switching from current full LTO usage over to ThinLTO. This Fedora 47 change proposal still needs to be voted on by the Fedora Engineering and Steering Committee (FESCo).