We have multiple places in code where we try to identify whether or not
some instruction is a guard. This patch factors out this logic into a separate
utility function which works uniformly in all places.
Differential Revision: https://reviews.llvm.org/D51152
Reviewed By: fedor.sergeev
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340921 91177308-0d34-0410-b5e6-96231b3b80d8