PR target/81708
	* config/i386/i386.opt (mstack-protector-guard-reg=): New option
	(mstack-protector-guard-offset=): Ditto.
	* config/i386/i386.c (ix86_option_override): Handle
	-mstack-protector-guard-reg= and -mstack-protector-guard-offset=
	options.
	(ix86_stack_protect_guard): Use ix86_stack_protect_guard_reg and
	ix86_stack_protect_guard_offset variables.
	(TARGET_STACK_PROTECT_GUARD): Always define.
	* doc/invoke.texi (x86 Options): Document -mstack-protector-guard-reg=
	and -mstack-protector-guard-offset= options.

testsuite/ChangeLog:

	PR target/81708
	* gcc.target/i386/stack-prot-guard.c: New test.

From-SVN: r250965