be: Pass an 'irg' instead of an 'obst' to 'be_create_reg_req()'.

ir/be/bearch.c

@@ -158,8 +158,9 @@ int be_default_is_valid_clobber(char const *const clobber)
 	return false;
 }
 
-arch_register_req_t const *be_create_reg_req(struct obstack *const obst, arch_register_t const *const reg, bool const ignore)
+arch_register_req_t const *be_create_reg_req(ir_graph *const irg, arch_register_t const *const reg, bool const ignore)
 {
+	struct obstack              *const obst    = be_get_be_obst(irg);
 	arch_register_class_t const *const cls     = reg->cls;
 	unsigned                    *const limited = rbitset_obstack_alloc(obst, cls->n_regs);
 	rbitset_set(limited, reg->index);

ir/be/bearch.h

@@ -388,6 +388,6 @@ void arch_copy_irn_out_info(ir_node *dst, unsigned dst_pos, ir_node const *src);
 
 int be_default_is_valid_clobber(char const *clobber);
 
-arch_register_req_t const *be_create_reg_req(struct obstack *obst, arch_register_t const *reg, bool ignore);
+arch_register_req_t const *be_create_reg_req(ir_graph *irg, arch_register_t const *reg, bool ignore);
 
 #endif

ir/be/benode.c

@@ -517,7 +517,7 @@ ir_node *be_new_Start(ir_graph *const irg, be_start_out const *const outs)
 		if (outs[i] != BE_START_NO) {
 			arch_register_t     const *const reg = &regs[i];
 			arch_register_req_t const *const req = outs[i] == BE_START_IGNORE
-				? be_create_reg_req(be_get_be_obst(irg), reg, true)
+				? be_create_reg_req(irg, reg, true)
 				: reg->single_req;
 			arch_set_irn_register_req_out(start, l, req);
 			arch_set_irn_register_out(    start, l, reg);

ir/be/bestack.c

@@ -198,8 +198,7 @@ void be_fix_stack_nodes(ir_graph *const irg, arch_register_t const *const sp)
 	be_irg_t *const birg = be_birg_from_irg(irg);
 	const arch_register_req_t *sp_req;
 	if (!rbitset_is_set(birg->allocatable_regs, sp->global_index)) {
-		struct obstack *const obst = be_get_be_obst(irg);
-		sp_req = be_create_reg_req(obst, sp, true);
+		sp_req = be_create_reg_req(irg, sp, true);
 	} else {
 		sp_req = sp->single_req;
 	}