ir: Use foreach_irn_in{,_r}().

ir/be/amd64/amd64_finish.c

@@ -195,8 +195,8 @@ static void assure_should_be_same_requirements(ir_node *const node)
 			continue;
 
 		/* test if any other input is using the out register */
-		for (int i2 = 0, arity = get_irn_arity(node); i2 < arity; ++i2) {
-			const arch_register_t *reg = arch_get_irn_register_in(node, i2);
+		foreach_irn_in(node, i2, in) {
+			arch_register_t const *const reg = arch_get_irn_register(in);
 			if (reg == out_reg && (unsigned)i2 != same_pos) {
 				if (!is_amd64_irn(node))
 					panic("cannot fulfill should_be_same on non-amd64 node");

ir/be/bechordal_main.c

@@ -144,8 +144,7 @@ static void dump(unsigned mask, ir_graph *irg,
 static void memory_operand_walker(ir_node *irn, void *env)
 {
 	(void)env;
-	for (int i = 0, arity = get_irn_arity(irn); i < arity; ++i) {
-		ir_node *in = get_irn_n(irn, i);
+	foreach_irn_in(irn, i, in) {
 		if (!arch_irn_is(skip_Proj(in), reload))
 			continue;
 		if (get_nodes_block(in) != get_nodes_block(irn))

ir/ir/irnode.c

@@ -534,8 +534,7 @@ void remove_End_n(ir_node *n, int idx)
 void remove_End_keepalive(ir_node *end, const ir_node *irn)
 {
 	assert(END_KEEPALIVE_OFFSET == 0);
-	for (unsigned i = get_irn_arity(end); i-- > 0; ) {
-		const ir_node *ka = get_irn_n(end, i);
+	foreach_irn_in_r(end, i, ka) {
 		if (ka == irn) {
 			remove_irn_n(end, i);
 			return;

ir/opt/jumpthreading.c

@@ -445,8 +445,7 @@ static ir_node *find_const_or_confirm(jumpthreading_env_t *env, ir_node *jump,
 		if (get_nodes_block(value) != block)
 			return NULL;
 
-		for (int i = 0, arity = get_irn_arity(value); i < arity; ++i) {
-			ir_node *phi_pred   = get_Phi_pred(value, i);
+		foreach_irn_in(value, i, phi_pred) {
 			ir_node *cfgpred    = get_Block_cfgpred(block, i);
 			ir_node *copy_block = find_const_or_confirm(env, cfgpred, phi_pred);
 			if (copy_block == NULL)
@@ -496,8 +495,7 @@ static ir_node *find_candidate(jumpthreading_env_t *env, ir_node *jump,
 		if (get_nodes_block(value) != block)
 			return NULL;
 
-		for (int i = 0, arity = get_irn_arity(value); i < arity; ++i) {
-			ir_node *phi_pred   = get_Phi_pred(value, i);
+		foreach_irn_in(value, i, phi_pred) {
 			ir_node *cfgpred    = get_Block_cfgpred(block, i);
 			ir_node *copy_block = find_candidate(env, cfgpred, phi_pred);
 			if (copy_block == NULL)