[llvm] [SROA] When unfolding gep of phi, insert gep into predecessor (PR #127652)

[Nikita Popov via llvm-commits]

nikic wrote:

The llvm-opt-benchmark diff doesn't look particularly compelling... Given that this didn't fix my motivating problem, maybe it's better to leave it as-is.

https://github.com/llvm/llvm-project/pull/127652