[llvm] [slp] fix scheduler deadlock for copyable users of vectorized instructions (PR #176661)

[Alexey Bataev via llvm-commits]

https://github.com/alexey-bataev commented:

The bug is fixed.  
BTW, not sure your fix is still correct. Need to check all nodes of all parent scalars, which are non-schedulable. 


https://github.com/llvm/llvm-project/pull/176661