[llvm] [llvm][ARM]Add ARM widen strings pass (PR #107120)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Can you give a brief example of Arm asm before/after this optimization?

I suspect this generalizes to other targets, at least in some cases.

Is there some reason we can't pad globals that aren't strings?

Padding out strings probably affects string merging in the linker, so the codesize tradeoff here is sort of hard to compute.

https://github.com/llvm/llvm-project/pull/107120