re PR target/15417 (ICE while building an avr-cross compiler)

	PR target/15417
	* config/avr/avr.c (avr_hard_regno_mode_ok): Enable usage of
	frame pointer register only in Pmode while reload in progress.

From-SVN: r86842

gcc/ChangeLog

+2004-08-31  Denis Chertykov  <denisc@overta.ru>
+
+	PR target/15417
+	* config/avr/avr.c (avr_hard_regno_mode_ok): Enable usage of
+	frame pointer register only in Pmode while reload in progress.
+
 2004-08-31  Stephane Carrez  <stcarrez@nerim.fr>
 
 	PR target/15334

gcc/config/avr/avr.c

@@ -5125,6 +5125,12 @@ avr_hard_regno_mode_ok (int regno, enum machine_mode mode)
   if (regno == REG_Y + 1)
     return 0;
 
+  /* Reload can use r28:r29 for reload register and for frame pointer
+   in one insn. It's wrong. We must disable it.  */
+  if (mode != Pmode && reload_in_progress && frame_pointer_required_p ()
+      && regno <= REG_Y && (regno + GET_MODE_SIZE (mode)) >= (REG_Y + 1))
+    return 0;
+
   if (mode == QImode)
     return 1;
   /*  if (regno < 24 && !AVR_ENHANCED)