Ensure r0/ref isn't clobbered by call.
Ensure r0/ref isn't clobbered by call.

Change-Id: Ic45dac1feb0b45cccfd72589ecee9ea74ee6d869

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst