[llvm] [ArgPromotion] Handle pointer arguments of recursive calls (PR #78735)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Please put comments in each of the test files briefly explaining what you're looking for.

For "multiple elements", I mean aggregate promotion, like llvm/test/Transforms/ArgumentPromotion/aggregate-promote.ll

https://github.com/llvm/llvm-project/pull/78735