Add LICENSE.TXT covering contributions made by ARM.

Absent a Contributor's License Agreement (CLA) with an LLVM legal entity and as
reviewed and agreed with Chris Lattner, add a patent license covering future
contributions from ARM until there is a CLA. This is to make explicit ARM's
grant of patent rights to recipients of LLVM containing ARM-contributed
material.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171721 91177308-0d34-0410-b5e6-96231b3b80d8
Switch BBVectorize to directly depend on having a TTI analysis.

This could be simplified further, but Hal has a specific feature for
ignoring TTI, and so I preserved that.

Also, I needed to use it because a number of tests fail when switching
from a null TTI to the NoTTI nonce implementation. That seems suspicious
to me and so may be something that you need to look into Hal. I worked
it by preserving the old behavior for these tests with the flag that
ignores all target info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171722 91177308-0d34-0410-b5e6-96231b3b80d8
Merge the unused header file for LoopVectorizer into the source file.
This makes the loop vectorizer match the pattern followed by roughly all
other passses. =]

Notably, this header file was braken in several regards: it contained
a using namespace directive, global #define's that aren't globaly
appropriate, and global constants defined directly in the header file.

As a side benefit, lots of the types in this file become internal, which
will cause the optimizer to chew on this pass more effectively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171723 91177308-0d34-0410-b5e6-96231b3b80d8