AMDGPU: Implement {{s|u}}int_to_fp i64 -> f32

The old lowering for uint_to_fp failed opencl conformance.
It might be OK for fast math mode, but I'm not sure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257393 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed