[llvm] [Draft] Support save/restore point splitting in shrink-wrap (PR #119359)

[Philip Reames via llvm-commits]

preames wrote:

Just for record keeping, a prior round of results can be found here: https://discourse.llvm.org/t/shrink-wrap-save-restore-points-splitting/83581/7.  They seem to roughly match the current results, though deepsjeng does show a small improvement.  

https://github.com/llvm/llvm-project/pull/119359