Fix a couple issues with Win64 ABI

1) all registers were spilled as xmm, regardless of actual size
2) win64 abi doesn't do the varargs-size-in-%al thing

Still to look into:

xmm6-15 are marked as clobbered by call instructions on win64 even though they aren't.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109035 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed