Pull in r191711 from upstream llvm trunk:

Pull in r191711 from upstream llvm trunk:

  The X86FixupLEAs pass for Intel Atom must not call
  convertToThreeAddress on ADD16rr opcodes, if src1 != src, since that
  would cause convertToThreeAddress to try to create a virtual register.
  This is not permitted after register allocation, which is when the
  X86FixupLEAs pass runs.

  This patch fixes PR16785.

Pull in r191715 from upstream llvm trunk:

  Forgot to add a break statement.

This should enable building the x11-toolskits/libXaw port with
CPUTYPE=atom.

Approved by:	re (gjb)
Reported by:	Kenta Suzumoto <kentas@hush.com>
MFC after:	3 days