Hi, I have spent some time to add additional logic in llvm BPF backend in order to generate verifier friendly code. The first patch is: https://reviews.llvm.org/D87153 which moves CORE relocation builtin handling from in late IR optimization (after inlining and major optimizations) to in early IR optimization (before inlining and any optimizations). The reason is to prevent harmful CSEs. But this change may change how compiler do optimizations. The patch can pass bpf selftests in latest bpf-next. Andrii helped it can also pass bcc/libbpf-tools. If your code uses COREs, esp. having a lot of subroutines and/or loops, it would be good to give a try with new patch to see whether there are any issues or not. In my case, for one of our internal applications with lots of subroutines and loops, inlining all subroutines and unrolling all loops will cause register spills which cannot be handled by the verifier, while existing llvm won't have issue. FYI, I have two more patches (still need tuning) in pipeline: https://reviews.llvm.org/D85570 to serialize code across control flows https://reviews.llvm.org/D87428 to avoid repeated condition evaluation Thanks, Yonghong
