Index: avr.c
===================================================================
--- avr.c	(revision 113395)
+++ avr.c	(working copy)
@@ -126,20 +126,26 @@
 /* Assembler only.  */
 int avr_asm_only_p = 0;
 
+/* Usually holds the value 2, but could be 3 for the larger devices with a
+   3-byte program counter.  */
+int avr_pc_size = 2;
+
 struct base_arch_s {
   int asm_only;
   int enhanced;
   int mega;
+  int three_byte_pc;
   const char *const macro;
 };
 
 static const struct base_arch_s avr_arch_types[] = {
-  { 1, 0, 0, NULL },  /* unknown device specified */
-  { 1, 0, 0, "__AVR_ARCH__=1" },
-  { 0, 0, 0, "__AVR_ARCH__=2" },
-  { 0, 0, 1, "__AVR_ARCH__=3" },
-  { 0, 1, 0, "__AVR_ARCH__=4" },
-  { 0, 1, 1, "__AVR_ARCH__=5" }
+  { 1, 0, 0, 0, NULL },  /* unknown device specified */
+  { 1, 0, 0, 0, "__AVR_ARCH__=1" },
+  { 0, 0, 0, 0, "__AVR_ARCH__=2" },
+  { 0, 0, 1, 0, "__AVR_ARCH__=3" },
+  { 0, 1, 0, 0, "__AVR_ARCH__=4" },
+  { 0, 1, 1, 0, "__AVR_ARCH__=5" },
+  { 0, 1, 1, 1, "__AVR_ARCH__=6" }
 };
 
 struct mcu_type_s {
@@ -209,6 +215,10 @@
   { "atmega128", 5, "__AVR_ATmega128__" },
   { "at90can128", 5, "__AVR_AT90CAN128__" },
   { "at94k",     5, "__AVR_AT94K__" },
+    /* 3-Byte PC */
+  { "avr6",      5, NULL },
+  { "atmega2560",     6, "__AVR_ATmega2560__" },
+  { "atmega2561",     6, "__AVR_ATmega2561__" },
     /* Assembler only.  */
   { "avr1",      1, NULL },
   { "at90s1200", 1, "__AVR_AT90S1200__" },
@@ -291,6 +301,11 @@
   avr_base_arch_macro = base->macro;
   avr_extra_arch_macro = t->macro;
 
+  if (base->three_byte_pc)
+    avr_pc_size = 3;
+  else
+    avr_pc_size = 2;
+
   if (optimize && !TARGET_NO_TABLEJUMP)
     avr_case_values_threshold = (!AVR_MEGA || TARGET_CALL_PROLOGUES) ? 8 : 17;
 
@@ -416,10 +431,10 @@
     return 0;
   else
     {
-      int offset = frame_pointer_needed ? 2 : 0;
+      int offset = frame_pointer_needed ? (avr_pc_size) : 0;
 
       offset += avr_regs_to_save (NULL);
-      return get_frame_size () + 2 + 1 + offset;
+      return get_frame_size () + (avr_pc_size) + 1 + offset;
     }
 }
 
Index: t-avr
===================================================================
--- t-avr	(revision 113395)
+++ t-avr	(working copy)
@@ -37,8 +37,8 @@
 
 FPBIT = fp-bit.c
 
-MULTILIB_OPTIONS = mmcu=avr2/mmcu=avr3/mmcu=avr4/mmcu=avr5
-MULTILIB_DIRNAMES = avr2 avr3 avr4 avr5
+MULTILIB_OPTIONS = mmcu=avr2/mmcu=avr3/mmcu=avr4/mmcu=avr5/mmcu=avr6
+MULTILIB_DIRNAMES = avr2 avr3 avr4 avr5 avr6
 
 # The many avr2 matches are not listed here - this is the default.
 MULTILIB_MATCHES = \
@@ -56,7 +56,8 @@
 	mmcu?avr5=mmcu?atmega325 mmcu?avr5=mmcu?atmega3250 \
 	mmcu?avr5=mmcu?atmega64  mmcu?avr5=mmcu?atmega128 \
 	mmcu?avr5=mmcu?atmega645 mmcu?avr5=mmcu?atmega6450 \
-	mmcu?avr5=mmcu?at94k mmcu?avr5=mmcu?at90can128
+	mmcu?avr5=mmcu?at94k mmcu?avr5=mmcu?at90can128 \
+	mmcu?avr6=mmcu?atmega2560 mmcu?avr6=mmcu?atmega2561
 
 MULTILIB_EXCEPTIONS =
 
Index: avr.h
===================================================================
--- avr.h	(revision 113395)
+++ avr.h	(working copy)
@@ -708,12 +708,13 @@
 
 #define CPP_SPEC "%{posix:-D_POSIX_SOURCE}"
 
-#define CC1_SPEC "%{profile:-p}"
+#define CC1_SPEC "%{profile:-p} -fno-delete-null-pointer-checks"
 
 #define CC1PLUS_SPEC "%{!frtti:-fno-rtti} \
     %{!fenforce-eh-specs:-fno-enforce-eh-specs} \
-    %{!fexceptions:-fno-exceptions}"
-/* A C string constant that tells the GCC drvier program options to
+    %{!fexceptions:-fno-exceptions} \
+    -fno-delete-null-pointer-checks"
+/* A C string constant that tells the GCC driver program options to
    pass to `cc1plus'.  */
 
 #define ASM_SPEC "%{mmcu=*:-mmcu=%*}"
@@ -723,6 +724,8 @@
 %{mmcu=attiny22|mmcu=attiny26|mmcu=at90s2*|mmcu=at90s4*|mmcu=at90s8*|mmcu=at90c8*|mmcu=at86rf401|mmcu=attiny13|mmcu=attiny2313:-m avr2}\
 %{mmcu=atmega103|mmcu=atmega603|mmcu=at43*|mmcu=at76*:-m avr3}\
 %{mmcu=atmega8*|mmcu=atmega48:-m avr4}\
+%{mmcu=atmega2560|mmcu=atmega2561:-m avr6}\
+%{mmcu=atmega2560|mmcu=atmega2561: -Tdata 0x800200}\
 %{mmcu=atmega16*|mmcu=atmega32*|mmcu=atmega64*|mmcu=atmega128|mmcu=at90can128|mmcu=at94k:-m avr5}\
 %{mmcu=atmega325|mmcu=atmega3250|mmcu=atmega48|mmcu=atmega88|mmcu=atmega64|mmcu=atmega645|mmcu=atmega6450|mmcu=atmega128|mmcu=at90can128|mmcu=at90can128|mmcu=atmega162|mmcu=atmega165|mmcu=atmega168|mmcu=atmega169: -Tdata 0x800100} "
 
@@ -786,7 +789,9 @@
 %{mmcu=atmega6450:crtm6450.o%s} \
 %{mmcu=atmega128:crtm128.o%s} \
 %{mmcu=at90can128:crtcan128.o%s} \
-%{mmcu=at94k:crtat94k.o%s}"
+%{mmcu=at94k:crtat94k.o%s}\
+%{mmcu=atmega2560:crtm2560.o%s} \
+%{mmcu=atmega2561:crtm2561.o%s}"
 
 #define EXTRA_SPECS {"crt_binutils", CRT_BINUTILS_SPECS},