[X86][SchedModel] Add missing scheduling model for SSE related instructions.

The patch defines new or refines existing generic scheduling classes to match
the behavior of the SSE instructions.
It also maps those scheduling classes on the related SSE instructions.

<rdar://problem/15607571>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202065 91177308-0d34-0410-b5e6-96231b3b80d8
SLPVectorizer: Try vectorizing 'splat' stores

Vectorize sequential stores of a broadcasted value.
5% on eon.

radar://16124699

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202067 91177308-0d34-0410-b5e6-96231b3b80d8