diff -Naurp gcc/config/avr/avr-devices.c gcc/config/avr/avr-devices.c
--- gcc/config/avr/avr-devices.c	2012-02-10 20:28:58.000000000 +0530
+++ gcc/config/avr/avr-devices.c	2012-02-10 20:29:40.000000000 +0530
@@ -289,6 +289,7 @@ const struct mcu_type_s avr_mcu_types[] 
   { "atxmega64a4u", ARCH_AVRXMEGA4, "__AVR_ATxmega64A4U__",         0, 0x2000, "x64a4u"},
   { "atxmega64b1",  ARCH_AVRXMEGA4, "__AVR_ATxmega64B1__",          0, 0x2000, "x64b1" },
   { "atxmega64b3",  ARCH_AVRXMEGA4, "__AVR_ATxmega64B3__",          0, 0x2000, "x64b3"},
+  { "atxmega64c3",  ARCH_AVRXMEGA4, "__AVR_ATxmega64C3__",          0, 0x2000, "x64c3"},
   { "atxmega64d3",  ARCH_AVRXMEGA4, "__AVR_ATxmega64D3__",          0, 0x2000, "x64d3" },
   { "atxmega64d4",  ARCH_AVRXMEGA4, "__AVR_ATxmega64D4__",          0, 0x2000, "x64d4" },
     /* Xmega, > 64K, <= 128K FLASH, > 64K RAM.  */
diff -Naurp gcc/config/avr/t-avr gcc/config/avr/t-avr
--- gcc/config/avr/t-avr	2012-02-10 20:28:58.000000000 +0530
+++ gcc/config/avr/t-avr	2012-02-10 20:29:40.000000000 +0530
@@ -299,6 +299,7 @@ MULTILIB_MATCHES = \
 	mmcu?avrxmega4=mmcu?atxmega64a4u \
 	mmcu?avrxmega4=mmcu?atxmega64b1 \
 	mmcu?avrxmega4=mmcu?atxmega64b3 \
+	mmcu?avrxmega4=mmcu?atxmega64c3 \
 	mmcu?avrxmega4=mmcu?atxmega64d3 \
 	mmcu?avrxmega4=mmcu?atxmega64d4 \
 	mmcu?avrxmega5=mmcu?atxmega64a1 \