[llvm] [llvm][RISCV] Implement Zilsd load/store pair optimization (PR #158640)

[Brandon Wu via llvm-commits]

4vtomat wrote:

> Before I do another review of this code, please can you once again go through the comments I've left and check that you've taken them into account? Even the ones you have marked resolved?
> 
I've gone through comments again and make sure it solves your comments and leave some comments on those cases that I'm not sure. The main concern is different symbol can't be fold and I also added a test case for interleaved symbol.

> Going forwards, please can you leave reviewers to mark their own comments as resolved - you've marked some of mine as resolved without actually fixing the underlying issues to my satisfaction. I don't know if this is because you made changes but had problems with git, or because I haven't been clear enough with where I see the problems, or something else.
Sorry about that, I click resolve when I push the fixup commits, I should leave reviewers to mark as resolved themselves.


https://github.com/llvm/llvm-project/pull/158640