PR libgcc/94513
	* generic-morestack.c: Give up trying to use __mmap/__munmap, use
	syscall instead.

	* generic-morestack.c: Only use __mmap on glibc >= 2.26.

	* generic-morestack.c: On GNU/Linux use __mmap/__munmap rather
	than mmap/munmap, to avoid hooks.

From-SVN: r279813

PR middle-end/71924 - missing -Wreturn-local-addr returning alloca result
PR middle-end/90549 - missing -Wreturn-local-addr maybe returning an address of a local array plus offset

gcc/ChangeLog:

	PR middle-end/71924
	PR middle-end/90549
	* gimple-ssa-isolate-paths.c (isolate_path): Add attribute.  Update
	comment.
	(args_loc_t): New type.
	(args_loc_t, locmap_t): same.
	(diag_returned_locals): New function.
	(is_addr_local): Same.
	(handle_return_addr_local_phi_arg, warn_return_addr_local): Same.
	(find_implicit_erroneous_behavior): Call warn_return_addr_local_phi_arg.
	(find_explicit_erroneous_behavior): Call warn_return_addr_local.

gcc/testsuite/ChangeLog:

	PR middle-end/71924
	PR middle-end/90549
	* gcc.c-torture/execute/return-addr.c: New test.
	* gcc.dg/Wreturn-local-addr-2.c: New test.
	* gcc.dg/Wreturn-local-addr-4.c: New test.
	* gcc.dg/Wreturn-local-addr-5.c: New test.
	* gcc.dg/Wreturn-local-addr-6.c: New test.
	* gcc.dg/Wreturn-local-addr-7.c: New test.
	* gcc.dg/Wreturn-local-addr-8.c: New test.
	* gcc.dg/Wreturn-local-addr-9.c: New test.
	* gcc.dg/Wreturn-local-addr-10.c: New test.
	* gcc.dg/Walloca-4.c: Handle expected warnings.
	* gcc.dg/pr41551.c: Same.
	* gcc.dg/pr59523.c: Same.
	* gcc.dg/tree-ssa/pr88775-2.c: Same.
	* gcc.dg/tree-ssa/alias-37.c: Same.
	* gcc.dg/winline-7.c: Same.

From-SVN: r273261