Optimizing LLVM's bump allocator
Summary
The article analyzes optimizations to LLVM's bump allocator (BumpPtrAllocator), detailing three changes: skipping unnecessary realignment for common cases, using a sentinel End to merge null checks, and removing per-allocation accounting. It presents the resulting fast-path code, generated assembly, and the aggregate compile-time impact, illustrating meaningful performance gains through inlining and reduced memory writes. This provides practical insights for high-performance C++/systems development and LLVM-based tooling.