[InstCombine] use m_APInt to allow icmp X, C folds for splat constant vectors

isSignBitCheck could be changed to take a pointer param to avoid the 'UnusedBit' ugliness.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281231 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed