[llvm] [PowerPC] Support PIC Secure PLT for CALL_RM (PR #121281)

[Brad Smith via llvm-commits]

brad0 wrote:

https://github.com/llvm/llvm-project/pull/72758

There was also a PR for the same fix. But for some reason George stopped responding.

https://github.com/llvm/llvm-project/pull/121281