[PATCH] [PowerPC] Initial VSX intrinsic support, with min/max for vector double

[Bill Schmidt]

Just recording a discussion point from LLVMdev:  Doing the check in DeclSpec::Finish() will work fine, but we need to be careful to get the caret for the diagnostic in the right place.  This will require adding a ninth location that will track where the "double" showed up in the decl, and using that loc appropriately in the diagnostic calls.

http://reviews.llvm.org/D5949