re PR target/42240 (wrong epilogue on naked function)

2011-02-22  Georg-Johann Lay  <avr@gjlay.de>

	PR target/42240
	* config/avr/avr.c (avr_cannot_modify_jumps_p): New function.
	(TARGET_CANNOT_MODIFY_JUMPS_P): Define.

From-SVN: r170534

gcc/ChangeLog

+2011-02-22  Georg-Johann Lay  <avr@gjlay.de>
+
+	PR target/42240
+	* config/avr/avr.c (avr_cannot_modify_jumps_p): New function.
+	(TARGET_CANNOT_MODIFY_JUMPS_P): Define.
+
 2011-02-26  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* doc/invoke.texi (ARC Options): Use CPU instead of cpu.

gcc/config/avr/avr.c

@@ -73,6 +73,7 @@ static void avr_file_end (void);
 static bool avr_legitimate_address_p (enum machine_mode, rtx, bool);
 static void avr_asm_function_end_prologue (FILE *);
 static void avr_asm_function_begin_epilogue (FILE *);
+static bool avr_cannot_modify_jumps_p (void);
 static rtx avr_function_value (const_tree, const_tree, bool);
 static void avr_insert_attributes (tree, tree *);
 static void avr_asm_init_sections (void);
@@ -217,6 +218,9 @@ static const struct default_options avr_option_optimization_table[] =
 #undef TARGET_OPTION_OPTIMIZATION_TABLE
 #define TARGET_OPTION_OPTIMIZATION_TABLE avr_option_optimization_table
 
+#undef TARGET_CANNOT_MODIFY_JUMPS_P
+#define TARGET_CANNOT_MODIFY_JUMPS_P avr_cannot_modify_jumps_p
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 static void
@@ -980,6 +984,27 @@ avr_asm_function_begin_epilogue (FILE *file)
   fprintf (file, "/* epilogue start */\n");
 }
 
+
+/* Implement TARGET_CANNOT_MODITY_JUMPS_P */
+
+static bool
+avr_cannot_modify_jumps_p (void)
+{
+
+  /* Naked Functions must not have any instructions after
+     their epilogue, see PR42240 */
+     
+  if (reload_completed
+      && cfun->machine
+      && cfun->machine->is_naked)
+    {
+      return true;
+    }
+
+  return false;
+}
+
+
 /* Return nonzero if X (an RTX) is a legitimate memory address on the target
    machine for a memory operand of mode MODE.  */