CellSPU:
- Fix fabs, fneg for f32 and f64.
- Use BuildVectorSDNode.isConstantSplat, now that the functionality exists
- Continue to improve i64 constant lowering. Lower certain special constants
  to the constant pool when they correspond to SPU's shufb instruction's
  special mask values. This avoids the overhead of performing a shuffle on a
  zero-filled vector just to get the special constant when the memory load
  suffices.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67067 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed