Teach the code generator that rlwimi is commutable if the rotate amount
is zero.  This lets the register allocator elide some copies in some cases.

This implements CodeGen/PowerPC/rlwimi-commute.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23292 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed