[PATCH] D42898: Do not spill CSR to stack on entry to noreturn functions

[Krzysztof Parzyszek via Phabricator via llvm-commits]

kparzysz added a comment.

By library function I simply meant a function that is provided by the user, which the compiler doesn't see the definition of.  The problem I remember seeing was that he didn't restore a callee-saved register, but I don't remember exactly where this was in relation to a noreturn function.  The code that we were compiling was written in C, not C++.  I suspect there was something similar to longjmp (but probably not a longjmp itself) somewhere in the user code that aborted some processing routines and "returned" to a top-level function.  It's just a guess though (I couldn't find that bug with a quick search).

My main concern here is that this should not be a default behavior for all targets.  As long as we have an option to opt out of this, I don't have objections, especially because a problematic case is not very common.  The added callback should take care of it.


https://reviews.llvm.org/D42898