[PATCH] D131521: [SDAG] avoid generating libcall in function with nobuiltin

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> I wonder how we build compiler-rt to avoid this dilemma?

We use ad-hoc solutions that happen to work.  For muloti, this particular multiply+divide pattern doesn't show up, so it's not a problem.  This basically works as long as compiler-rt and the compiler are tightly coupled.  It sort of breaks down when people try to build compiler-rt equivalents in other languages.  Given there's now at least three implementations that are built with LLVM (compiler-rt itself, zig, and rust), maybe a more principled solution is appropriate.

> I don't see `no-builtins` specifically in the LangRef; not sure if that was a typo or worse: undocumented IR attributes. *yikes*
> Oh, you weren't kidding: https://godbolt.org/z/o49oK6GYG *yikes*
> Well I sure wouldn't do anything with that attr until its semantics are well documented.

That should be documented, yes.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D131521/new/

https://reviews.llvm.org/D131521