RegBankSelect: Fix copy insertion point for terminators

If a copy was needed to handle the condition of brcond, it was being
inserted before the defining instruction. Add tests for iterator edge

I find the existing code here suspect for the case where it's looking
for terminators that modify the register. It's going to insert a copy
in the middle of the terminators, which isn't allowed (it might be
necessary to have a COPY_terminator if anybody actually needs this).

Also legalize brcond for AMDGPU.

git-svn-id: 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed