bfb9b8e075
We call tail-call-elim near the beginning of the pipeline, but that is too early to annotate calls that get added later. In the motivating case from issue #47852, the missing 'tail' on memset leads to sub-optimal codegen. I experimented with removing the early instance of tail-call-elim instead of just adding another pass, but that appears to be slightly worse for compile-time: +0.15% vs. +0.08% time. "tailcall" shows adding the pass; "tailcall2" shows moving the pass to later, then adding the original early pass back (so 1596886802 is functionally equivalent to 180b0439dc ): https://llvm-compile-time-tracker.com/index.php?config=NewPM-O3&stat=instructions&remote=rotateright Note that there was an effort to split the tail call functionality into 2 passes - that could help reduce compile-time if we find that this change costs more in compile-time than expected based on the preliminary testing: D60031 Differential Revision: https://reviews.llvm.org/D130374