In this article, I am going to talk about having a PGO (Profile-Guided Optimization) build of Clang. Qt Creator has had a PGO build of clangd (and previously libclang.dll ) on Windows x64 for quite a while now . This was a MinGW GCC build of clangd , since the MSVC compiler generated a slower PGO binary. With the update to Clang 22, the MinGW GNU compiler (13.1.0) was having issues performing the PGO build, which forced a different approach. This approach was the multi-stage PGO build of Clang itself. This is no longer exclusive to Windows x64; it is now available for all platforms ! The llvm.org documentation mentions: PGO (Profile-Guided Optimization) allows your compiler to better optimize code for how it actually runs. Users report that applying this to Clang and LLVM can decrease overall compile time by 20%. Test setup I have tested Qt Creator 19.0.2 (clangd 21.1.2) and Qt Creator 20.0.0 beta1 (clangd 22.1.2).…