[llvm] [InstCombine] [X86] pblendvb intrinsics must be replaced by select when possible (PR #137322)

[via llvm-commits]

vortex73 wrote:

> @vortex73 ping?

So sorry about the delay...
I tried a lot doing my way of the recursion - still haven't quire figured out why that didn't work (maybe just doesn't identify complex patterns)

I've implemented it as a vectorcombine transform like you suggested initially and it seems to be working. I shall clean up the tree and push the changes :)

https://github.com/llvm/llvm-project/pull/137322