[X86] Regcall - Adding support for mask types

Regcall calling convention passes mask types arguments in x86 GPR registers.
The review includes the changes required in order to support v32i1, v16i1 and v8i1.

Differential Revision: https://reviews.llvm.org/D27148



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289383 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed