avr.c (avr_hard_regno_mode_ok): Do not allow r29 which may overwrite the high byte...

	2002-02-28  Marek Michalkiewicz  <marekm@amelek.gda.pl>
	* config/avr/avr.c (avr_hard_regno_mode_ok): Do not allow r29
	which may overwrite the high byte of the frame pointer.

From-SVN: r53629

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a4aa495c2d9808869a67d6c855604e694888d0d5..9ee43b0f2159d392bcb85d3383f463bcd67b0ca9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2002-05-19  Marek Michalkiewicz  <marekm@amelek.gda.pl>
+
+       2002-02-28  Marek Michalkiewicz  <marekm@amelek.gda.pl>
+       * config/avr/avr.c (avr_hard_regno_mode_ok): Do not allow r29
+       which may overwrite the high byte of the frame pointer.
+
 2002-03-19  Lars Brinkhoff  <lars@nocrew.org>
 
        * emit-rtl.c (gen_int_mode): New function.

diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c
index 145751993a80841481002eaaa51bdb21ee340dbc..8e64bcb74aaed250e14701aa02ac43bd63a10188 100644 (file)
--- a/gcc/config/avr/avr.c
+++ b/gcc/config/avr/avr.c
@@ -5210,6 +5210,13 @@ avr_hard_regno_mode_ok (regno, mode)
      int regno;
      enum machine_mode mode;
 {
+  /* Bug workaround: recog.c (peep2_find_free_register) and probably
+     a few other places assume that the frame pointer is a single hard
+     register, so r29 may be allocated and overwrite the high byte of
+     the frame pointer.  Do not allow any value to start in r29.  */
+  if (regno == REG_Y + 1)
+    return 0;
+
   if (mode == QImode)
     return 1;
   /*  if (regno < 24 && !AVR_ENHANCED)