[AMDGPU] add s_incperflevel/s_decperflevel intrinsics.

Differential revision: https://reviews.llvm.org/D23666

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279106 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed