[ScheduleDAGInstrs] isUnsafeMemoryObject() removed
[ScheduleDAGInstrs] isUnsafeMemoryObject() removed

This function was basically useless, since volatile memacesses or MIs with
unmodelled sideffects become global memory objects, and the other little
checks are also done elsewhere.

Reviewed by Andy Trick
http://reviews.llvm.org/D16881

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260899 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit d7ffe9a12e639d3c282b95af6252187ca15a1dab)

This is related to rdar://problem/21836011

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm