[PATCH] D129677: Disable machine function splitting for functions with inline asm br

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

AArch64 "b" has a range of +-128MB.  Which isn't enough for arbitrary programs.  So in general, you need a sequence like the following (assuming small code model):

  adrp x0, dest
  add x0, x0, :lo12:dest
  blr x0

That is, unless you're okay with the restriction that your binary is at most 128MB.  Which might be reasonable for the Linux kernel, I guess.  But again, something you'd want to document...

------

That said, I'm surprised machine function splitting on aarch64 works without any other changes; currently, branch relaxation isn't aware of section markings at all.  Or do you have some other out-of-tree patches?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D129677/new/

https://reviews.llvm.org/D129677