[llvm] [RISCV][VLOPT] Enable the RISCVVLOptimizer by default (PR #119461)

[Michael Maitland via llvm-commits]

michaelmaitland wrote:

> > Should we just remove this code for now
> 
> This would be fine by me. Incrementalism is good. :)

I've removed it in https://github.com/llvm/llvm-project/pull/120291.

FWIW, I don't think what you're concerned about can happen with or without https://github.com/llvm/llvm-project/pull/120291 merged since all the instructions that isVectorOpUsedAsScalarOp deal with return `OperandInfo(Unknown)` and won't lead to any (incorrect) optimization.

https://github.com/llvm/llvm-project/pull/119461