[llvm] [X86] Add test for VPBLENDW Tuning (PR #179906)

[via llvm-commits]

mahesh-attarde wrote:

> @mahesh-attarde ping?


Apologies for delay @RKSimon.
I took time to understand exactly your point on this.
I see you insisted `-mcpu` to kick of scheduler tuning. This would mean to address it across Intel {sandybridge,haswell,skylake,alderlake} and AMD {zenver1, zenver2}
Interesting Cases:
  - sandybridge — AVX only, no conversion
  - haswell — AVX2, Intel sched model, converts VPBLENDW->VPBLENDD
  - znver1 — AVX2, AMD sched model, does NOT convert

Others were duplicates.

https://github.com/llvm/llvm-project/pull/179906