There may be some BB to COPY fgr64cc register, and the fgr64cc register
is set by the previous BB.
We add a new pass called MipsSetMachineRegisterFlags, in which we set
We introduce a new pass called MipsSetMachineRegisterFlags, in which we
set NoSWrap flag for all instructions that works with fgr64cc registers.
And in copyPhyRegister, we allow the COPY instruction with NoSignWrap
from the double float registers to gpr32.
472c8f8d96