* alpha.c (alpha_return_addr_rtx): New variable.
(alpha_save_machine_status): New; save it.
(alpha_restore_machine_status): New; restore it.
(alpha_init_expanders): New; clear it.
(alpha_return_addr): New; set it.
(alpha_ra_ever_killed): New; if alpha_return_addr_rtx, regs_ever_live
is overly conservative, so search the insns explicitly.
(alpha_sa_mask [VMS]): Check alpha_ra_ever_killed.
(alpha_sa_size [VMS && !VMS]): Likewise.
* alpha.h (RETURN_ADDR_RTX): Call alpha_return_addr.
(INIT_EXPANDERS): New definition.
* alpha.c: Move REG_PV, REG_RA somewhere more visible in the file.
(output_prolog [!VMS]): Use them.
* alpha.c (output_prolog [!VMS]): Move gp detection to ...
(alpha_does_function_need_gp): ... a new function. Refine the
CALL_INSN test to just TYPE_JSR.
* alpha.md (most call insns): Fix some jsr/ibr type transpositions.
From-SVN: r15936
