[llvm] [BPF] Define set of BPF libcalls (PR #169537)

[Lucas Ste via llvm-commits]

LucasSte wrote:

> Sorry for the ping. On a second look, I need to rethink this change a little bit. While it was suggested that we tell which lib calls are available for BPF, if I simply say `__udivti3` is not available, I get a codegen error `unsupported library call operation`.

i128 will always expand in LLVM for BPF, so the DAG legalizer will call `ExpandIntRes_UDIV` for udiv, which will always invoke the lib call.

I might be missing something, but I believe the change in this PR is not possible.

https://github.com/llvm/llvm-project/pull/169537