[llvm] [RISCV] Remove custom isel lowering of i64 to Zilsd load/store. (PR #169067)

[Craig Topper via llvm-commits]

topperc wrote:

I think we have to keep the SelectionDAG code for volatile loads/stores. If we want to guarantee that an i64 volatile load/store stays as a 64-bit operation we can't rely on the ZilsdOptimizer.

https://github.com/llvm/llvm-project/pull/169067