gcc/c/ChangeLog:

	PR c/83656
	* c-decl.c (header_for_builtin_fn): Declare.
	(diagnose_mismatched_decls): Diagnose declarations of built-in
	functions without a prototype.
	* c-typeck.c (maybe_warn_builtin_no_proto_arg): New function.
	(convert_argument): Same.
	(convert_arguments): Factor code out into convert_argument.
	Detect mismatches between built-in formal arguments in calls
	to built-in without prototype.
	(build_conditional_expr): Same.
	(type_or_builtin_type): New function.
	(convert_for_assignment): Add argument.  Conditionally issue
	warnings instead of errors for mismatches.

gcc/testsuite/ChangeLog:

	PR c/83656
	* gcc.dg/20021006-1.c
	* gcc.dg/Wbuiltin-declaration-mismatch.c: New test.
	* gcc.dg/Wbuiltin-declaration-mismatch-2.c: New test.
	* gcc.dg/Wbuiltin-declaration-mismatch-3.c: New test.
	* gcc.dg/Wbuiltin-declaration-mismatch-4.c: New test.
	* gcc.dg/Walloca-16.c: Adjust.
	* gcc.dg/Wrestrict-4.c: Adjust.
	* gcc.dg/Wrestrict-5.c: Adjust.
	* gcc.dg/atomic/stdatomic-generic.c: Adjust.
	* gcc.dg/atomic/stdatomic-lockfree.c: Adjust.
	* gcc.dg/initpri1.c: Adjust.
	* gcc.dg/pr15698-1.c: Adjust.
	* gcc.dg/pr69156.c: Adjust.
	* gcc.dg/pr83463.c: Adjust.
	* gcc.dg/redecl-4.c: Adjust.
	* gcc.dg/tls/thr-init-2.c: Adjust.
	* gcc.dg/torture/pr55890-2.c: Adjust.
	* gcc.dg/torture/pr55890-3.c: Adjust.
	* gcc.dg/torture/pr67741.c: Adjust.
	* gcc.dg/torture/stackalign/sibcall-1.c: Adjust.
	* gcc.dg/torture/tls/thr-init-1.c: Adjust.
	* gcc.dg/tree-ssa/builtins-folding-gimple-ub.c: Adjust.

From-SVN: r266194