sparc: use %g0 for 0 constants

[r27911]

diff --git a/ir/be/sparc/sparc_transform.c b/ir/be/sparc/sparc_transform.c
index 0eddf81..2bc4ca9 100644 (file)
--- a/ir/be/sparc/sparc_transform.c
+++ b/ir/be/sparc/sparc_transform.c
@@ -153,7 +153,7 @@ static ir_node *gen_extension(dbg_info *dbgi, ir_node *block, ir_node *op,
  * Creates a possible DAG for a constant.
  */
 static ir_node *create_const_graph_value(dbg_info *dbgi, ir_node *block,
-                               long value)
+                                         long value)
 {
        ir_node *result;
 
@@ -650,6 +650,11 @@ static ir_node *gen_Const(ir_node *node)
                return proj;
        }
 
+       /* use the 0 register instead of a 0-constant */
+       if (is_Const_null(node)) {
+               return be_prolog_get_reg_value(abihelper, &sparc_gp_regs[REG_G0]);
+       }
+
        return create_const_graph(node, block);
 }
 
@@ -975,6 +980,8 @@ static ir_node *gen_Start(ir_node *node)
        /* stackpointer is important at function prolog */
        be_prolog_add_reg(abihelper, sp_reg,
                        arch_register_req_type_produces_sp | arch_register_req_type_ignore);
+       be_prolog_add_reg(abihelper, &sparc_gp_regs[REG_G0],
+               arch_register_req_type_ignore);
        /* function parameters in registers */
        for (i = 0; i < get_method_n_params(function_type); ++i) {
                const reg_or_stackslot_t *param = &cconv->parameters[i];