A homogeneous aggregate is an aggregate data structure where after flattening
any nesting there are 1 to 4 elements of the same base type that is either a
float, double, or Neon vector. All Neon vectors of the same size, either 64
or 128 bits, are treated as equivalent for this purpose. When using the
AAPCS-VFP ABI, check for homogeneous aggregates and pass them as arguments by
expanding them into a sequence of their base types. This requires extending
the existing support for expanded arguments to handle not only structs, but
also constant arrays and complex types.
llvm-svn: 136767
Bob Wilson