This patch adds parsing support for the 'aarch64_vector_pcs'
calling convention attribute to calls and function declarations.
More information describing the vector ABI and procedure call standard
can be found here:
https://developer.arm.com/products/software-development-tools/\
hpc/arm-compiler-for-hpc/vector-function-abi
Reviewers: t.p.northover, rnk, rengolin, javed.absar, thegameg, SjoerdMeijer
Reviewed By: SjoerdMeijer
Differential Revision: https://reviews.llvm.org/D51477
llvm-svn: 342030
Sander de Smalen