- /* Before going on to check the call-saved registers we can try a couple
- more ways of deducing that r3 is available. The first is when we are
- pushing anonymous arguments onto the stack and we have less than 4
- registers worth of fixed arguments(*). In this case r3 will be part of
- the variable argument list and so we can be sure that it will be
- pushed right at the start of the function. Hence it will be available
- for the rest of the prologue.
- (*): ie crtl->args.pretend_args_size is greater than 0. */
- if (cfun->machine->uses_anonymous_args
- && crtl->args.pretend_args_size > 0)
- return LAST_ARG_REGNUM;
-
- /* The other case is when we have fixed arguments but less than 4 registers
- worth. In this case r3 might be used in the body of the function, but
- it is not being used to convey an argument into the function. In theory
- we could just check crtl->args.size to see how many bytes are
- being passed in argument registers, but it seems that it is unreliable.
- Sometimes it will have the value 0 when in fact arguments are being
- passed. (See testcase execute/20021111-1.c for an example). So we also
- check the args_info.nregs field as well. The problem with this field is
- that it makes no allowances for arguments that are passed to the
- function but which are not used. Hence we could miss an opportunity
- when a function has an unused argument in r3. But it is better to be
- safe than to be sorry. */
- if (! cfun->machine->uses_anonymous_args
- && crtl->args.size >= 0
- && crtl->args.size <= (LAST_ARG_REGNUM * UNITS_PER_WORD)
- && (TARGET_AAPCS_BASED
- ? crtl->args.info.aapcs_ncrn < 4
- : crtl->args.info.nregs < 4))
- return LAST_ARG_REGNUM;
-