r361845 changed the way we handle "D16" vs. "D32" targets; there used to be a negative "d16" which removed instructions from the instruction set, and now there's a "d32" feature which adds instructions to the instruction set. This is good, but there was an oversight in the implementation: the behavior of VFPv2 was changed. In particular, the "vfp2" feature was changed to imply "d32". This is wrong: VFPv2 only supports 16 D registers.
In practice, this means if you specify -mfpu=vfpv2, the compiler will generate illegal instructions.
This patch gets rid of "vfp2d16" and "vfp2d16sp", and fixes "vfp2" and "vfp2sp" so they don't imply "d32".
(There are a couple minor corresponding changes to clang; I'll post a corresponding patch soon.)