[PATCH] [AArch64] Add register spill code for large super registers such as DPair, DTriple ...

[Hao Liu]

  As in the last commit I removed the code for spilling/filling D tuples, I re-add D tuple spill/fill code again.

  There is still no test cases for D tuples, as the original test cases are too large (hundreds of lines) and difficult to be simplified. The situation of D tuples is similar to Q tuples, so we don't need to worry too much about the correctness of D tuples.

  Committed in http://llvm.org/viewvc/llvm-project?view=revision&revision=198684.

  Thanks,
  -Hao

http://llvm-reviews.chandlerc.com/D2438