R600: Replace legacy debug code in AMDILCFGStructurizer.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186723 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Simplify AMDILCFGStructurize by removing templates and assuming single exit

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186724 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Don't emit empty then clause and use alu_pop_after

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186725 91177308-0d34-0410-b5e6-96231b3b80d8