Hi! I’d like to share some performance results on AArch64 using PGO and BOLT. The attached graph illustrates the speedup, measured as seen with the elapsed time for a parallel build of bin/clang (version 19.1.6, built with clang-19.1.6). In each case, instrumented profiles were used with a build of libLLVMSupport used as training data.
It highlights the impact of various PGO techniques on AArch64. The Clang/BOLT version under test is main @ 2025-01-18, close to LLVM 20.
