Recognize Intel 4th-Generation Core processors (Haswell) machines.
The patch also fixes a problem for "Penryn" machines with SSE 4.1.
The modifications to LLVM 3.3 were copied line-by-line from LLVM 3.4.
Merge pull request #7155 from ArchRobison/adr/haswell

Enable AVX for  Intel 4th-Generation Core processor ("Haswell") .