Added tests for shufflevector lowering to blend instrs.

These tests ensure that a change I will propose in clang works as
expected.

Summary:
Added tests for the generation of blend+immediate instructions from a
shufflevector.
These tests were proposed along with a patch that was dropped. I'm
committing the tests anyway to protect against possible regressions in
codegen.

Reviewers: nadav, bkramer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D3600

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209853 91177308-0d34-0410-b5e6-96231b3b80d8
LoopVectorizer: Add a check that the backedge taken count + 1 does not overflow

The loop vectorizer instantiates be-taken-count + 1 as the loop iteration count.
If this expression overflows the generated code was invalid.

In case of overflow the code now jumps to the scalar loop.

Fixes PR17288.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209854 91177308-0d34-0410-b5e6-96231b3b80d8
Sync list of targets with configure's reality



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209855 91177308-0d34-0410-b5e6-96231b3b80d8