PPC MCRF instruction does not have side effects

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178971 91177308-0d34-0410-b5e6-96231b3b80d8
PPC pre-increment load instructions do not have side effects

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178972 91177308-0d34-0410-b5e6-96231b3b80d8