[InstCombine] allow icmp (and X, C2), C1 folds for splat constant vectors

The code to calculate 'UsesRemoved' could be simplified.
As-is, that code is a victim of PR30273:
https://llvm.org/bugs/show_bug.cgi?id=30273



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280637 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed