6.6.11.3 -ffixed-reg
Treat the register named reg as a fixed register; generated code should never refer to it (except perhaps as a Stack Pointer, Frame Pointer or in some other fixed role).
reg must be the name of a register, e.g., -ffixed-w3.
Treat the register named reg as a fixed register; generated code should never refer to it (except perhaps as a Stack Pointer, Frame Pointer or in some other fixed role).
reg must be the name of a register, e.g., -ffixed-w3.