[llvm] [SelectionDAG][RISCV] Avoid store merging across function calls (PR #130430)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> This patch improves DAGCombiner's handling of potential store merges by
detecting function calls between loads and stores. 

I'm surprised this even happens. What happens if you just do this unconditionally? 

https://github.com/llvm/llvm-project/pull/130430