[llvm] [LLVM][SVE] Honour calling convention when using SVE for fixed length vectors. (PR #70847)

[Paul Walker via llvm-commits]

paulwalker-arm wrote:

Fallback to calling base versions of getRegisterTypeForCallingConv and getNumRegistersForCallingConv for unit-length vectors. Extending testing to cover unit-length vectors.

https://github.com/llvm/llvm-project/pull/70847