[InstSimplify] handle all icmp i1 X, C in one place; NFCI
We already handled all of the new tests identically, but several
of those went through a lot of unnecessary processing before
getting folded.
Another motivation for grouping these cases together is that
InstCombine needs a similar fold. Currently, it handles the
'not' cases inefficiently which can lead to bugs as described
in the post-commit comments of:
https://reviews.llvm.org/D32143
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303295 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed