* i386.c (struct machine_function): Add save_varrargs_registers.
(ix86_save_varrargs_registers): New macro.
(ix86_frame_layout): Support 64bit; support red zones and varrargs area.
(ix86_expand_prologue): Likewise.
(ix86_emit_epilogue_esp_adjustement): Likewise.
(ix86_expand_epilogue): Likewise.
* i386.md (pro_epilogue_adjust_stack): Turn to expander; support 64bit.
(pro_epilogue_adjust_stack_1): New insn.
(pro_epilogue_adjust_stack_rex64): Likewise.
* i386.h (MASK_NO_RED_ZONE): New constant.
(TARGET_RED_ZONE): New macro.
(TARGET_OPTIONS): Add "red-zone" and "no-red-zone"
(RED_ZONE_SIZE): New constant.
(RED_ZONE_RESERVE): New constant.
From-SVN: r40846
