s
  -mno-regnames           do not allow symbolic names for registers
  -mwarn-areg-zero        warn about base/index register zero
  -mwarn-regtype-mismatch=strict
                          warn about register name type mismatches
  -mwarn-regtype-mismatch=relaxed
                          warn about register name type mismatches,
                          but allow FPR and VR to be used interchangeably
  -mno-warn-regtype-mismatch
                          do not warn about register name type mismatches