[llvm] [VPlan] Preserve underlying value when EVL transforming intrinsics/casts (PR #121552)

[Elvis Wang via llvm-commits]

ElvisWang123 wrote:

> Does #113903 fix the issue? cc @ElvisWang123

Currently, not. 
I haven't support EVL-transform for extended-reduction and mul-acc-reduction in #113903 yet. 
I think we still need this patch to preserve the underlying instruction in the EVL transform.
And I am not sure will the induction skips some cost calculation of  `cast` instruction.

https://github.com/llvm/llvm-project/pull/121552