[llvm] [RISCV] Allow VCIX with SE to reorder (PR #77049)

[Craig Topper via llvm-commits]

topperc wrote:

> This patch sets HasSideEffect to 0, it allows VCIX instructions
that have side effect to be reordered.

This description needs to be improved. We don't want the VCIX instructions to be reordered relative to each other. We just want them to be able to reorder with memory and other side effecting instructions.

Should also mention the VCIX_STATE.

https://github.com/llvm/llvm-project/pull/77049