[InstCombine] add tests for add-of-sext-bool; NFC

We canonicalize to select with a zext-add and either zext-sub or sext-sub,
so this shows a pattern that's not conforming to the general trend.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335506 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed