Merging r221009:

Correctly update dom-tree after loop vectorizer.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@223531 91177308-0d34-0410-b5e6-96231b3b80d8
Merging r223170:

Apply loop-rotate to several vectorizer tests.

Such loops shouldn't be vectorized due to the loops form.
After applying loop-rotate (+simplifycfg) the tests again start to check
what they are intended to check.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@223534 91177308-0d34-0410-b5e6-96231b3b80d8
Merging r223171:

PR21302. Vectorize only bottom-tested loops.

rdar://problem/18886083


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@223535 91177308-0d34-0410-b5e6-96231b3b80d8