Revert patch. Something snuck in there that shouldn't be.

--- Reverse-merging r171441 into '.':
U    include/llvm/IR/Attributes.h
U    lib/IR/Attributes.cpp




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171444 91177308-0d34-0410-b5e6-96231b3b80d8
LoopVectorizer: Document the unrolling feature.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171445 91177308-0d34-0410-b5e6-96231b3b80d8
LoopVectorizer: Test the unrolling flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171446 91177308-0d34-0410-b5e6-96231b3b80d8