[compiler-rt] [llvm] [AArch64] Implement INIT/ADJUST_TRAMPOLINE (PR #70267)

[Carlos Seo via llvm-commits]

ceseo wrote:

> Yes, it will be great to have this for LLVM 19 since this enables an important HPC application.

I'll just make the small changes requested by @MaskRay and resubmit the final version.

https://github.com/llvm/llvm-project/pull/70267