(expand_function_start): Don't set up context_display

        unless current_function_needs_context.

From-SVN: r11615

gcc/function.c

@@ -5230,12 +5230,16 @@ expand_function_start (subr, parms_have_cleanups)
 	use_variable (current_function_internal_arg_pointer);
     }
 
+  context_display = 0;
+  if (current_function_needs_context)
+    {
       /* Fetch static chain values for containing functions.  */
       tem = decl_function_context (current_function_decl);
       /* If not doing stupid register allocation copy the static chain
-     pointer into a pseudo.  If we have small register classes, copy the
-     value from memory if static_chain_incoming_rtx is a REG.  If we do
-     stupid register allocation, we use the stack address generated above.  */
+	 pointer into a pseudo.  If we have small register classes, copy
+	 the value from memory if static_chain_incoming_rtx is a REG.  If
+	 we do stupid register allocation, we use the stack address
+	 generated above.  */
       if (tem && ! obey_regdecls)
 	{
 #ifdef SMALL_REGISTER_CLASSES
@@ -5249,7 +5253,6 @@ expand_function_start (subr, parms_have_cleanups)
 	  last_ptr = copy_to_reg (static_chain_incoming_rtx);
 	}
 
-  context_display = 0;
       while (tem)
 	{
 	  tree rtlexp = make_node (RTL_EXPR);
@@ -5273,6 +5276,7 @@ expand_function_start (subr, parms_have_cleanups)
 	    save_expr_regs = gen_rtx (EXPR_LIST, VOIDmode, last_ptr,
 				      save_expr_regs);
 	}
+    }
 
   /* After the display initializations is where the tail-recursion label
      should go, if we end up needing one.   Ensure we have a NOTE here