i386: Change indirect_return to function type attribute

i386: Change indirect_return to function type attribute

In

struct ucontext;
typedef struct ucontext ucontext_t;

extern int (*bar) (ucontext_t *__restrict __oucp,
                   const ucontext_t *__restrict __ucp)
  __attribute__((__indirect_return__));

extern int res;

void
foo (ucontext_t *oucp, ucontext_t *ucp)
{
  res = bar (oucp, ucp);
}

bar() may return via indirect branch.  This patch changes indirect_return
to type attribute to allow indirect_return attribute on variable or type
of function pointer so that ENDBR can be inserted after call to bar().

gcc/

	PR target/86560
	* config/i386/i386.c (rest_of_insert_endbranch): Lookup
	indirect_return as function type attribute.
	(ix86_attribute_table): Change indirect_return to function
	type attribute.
	* doc/extend.texi: Update indirect_return attribute.

gcc/testsuite/

	PR target/86560
	* gcc.target/i386/pr86560-1.c: New test.
	* gcc.target/i386/pr86560-2.c: Likewise.
	* gcc.target/i386/pr86560-3.c: Likewise.

From-SVN: r262877