[LICM] Report failing to hoist a load with an invariant address

[LICM] Report failing to hoist a load with an invariant address

These are interesting because lack of precision in alias information
could be standing in the way of this optimization.

An example is the case in the test suite that I showed in the DevMeeting
talk:

http://lab.llvm.org:8080/artifacts/opt-view_test-suite/build/MultiSource/Benchmarks/FreeBench/distray/CMakeFiles/distray.dir/html/_org_test-suite_MultiSource_Benchmarks_FreeBench_distray_distray.c.html#L236

canSinkOrHoistInst is also used from LoopSink, which does not use
opt-remarks so we need to take ORE as an optional argument.

Differential Revision: https://reviews.llvm.org/D27939

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291648 91177308-0d34-0410-b5e6-96231b3b80d8