For PR950:

For PR950:
Add a new feature to FunctionType, Parameter Attributes. This allows tags
such as "sext" and "zext" to be associated with a faunction's arguments
or return type. This allows signedness information to be carried forward
from the frontend to the backend for arguments and result types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32776 91177308-0d34-0410-b5e6-96231b3b80d8