When using Greedy Register Allocation, there are times where
early-clobber values are ignored, and assigned the same register. This
is illeagal behaviour for these intructions. To get around this, using
Pseudo instructions for early-clobber registers gives them a definition
and allows Greedy to assign them to a different register. This then
meets the ARM Architecture Reference Manual and matches the defined
behaviour.
This patch takes the existing RISC-V patch and makes it target
independent, then adds support for the ARM Architecture. Doing this will
ensure early-clobber restraints are followed when using the ARM
Architecture. Making the pass target independent will also open up
possibility that support other architectures can be added in the future.