[LICM] Restructure implicit exit handling to be more clear [NFCI]

When going to explain this to someone else, I got tripped up by the complicated meaning of IsKnownNonEscapingObject in load-store promotion.  Extract a helper routine and clarify naming/scopes to make this a bit more obvious.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316699 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed