diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5d15a621f76..cd17c1f6019 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-09-06  Jesper Nilsson  <jesper.nilsson@axis.com>
+
+	* longlong.h [__CRIS_arch_version >= 8] (count_trailing_zeros):
+	Defined.
+	* config/cris/cris.md (ctzsi2, cris_swap_bits): Implemented.
+	* config/cris/cris.h (CTZ_DEFINED_VALUE_AT_ZERO): Defined.
+
 2007-09-06  Jie Zhang  <jie.zhang@analog.com>
 
 	* config.gcc (tm_file): Add linux.h for bfin*-uclinux*.
diff --git a/gcc/config/cris/cris.h b/gcc/config/cris/cris.h
index 7a2f714586e..3dd0dbd9511 100644
--- a/gcc/config/cris/cris.h
+++ b/gcc/config/cris/cris.h
@@ -1410,6 +1410,7 @@ enum cris_pic_symbol_type
 #define TRULY_NOOP_TRUNCATION(OUTPREC, INPREC) 1
 
 #define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) ((VALUE) = 32, 1)
+#define CTZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) ((VALUE) = 32, 1)
 
 #define Pmode SImode
 
diff --git a/gcc/config/cris/cris.md b/gcc/config/cris/cris.md
index 765bd8602c4..e248d4307ed 100644
--- a/gcc/config/cris/cris.md
+++ b/gcc/config/cris/cris.md
@@ -69,7 +69,8 @@
    (CRIS_UNSPEC_GOT 2)
    (CRIS_UNSPEC_GOTREL 3)
    (CRIS_UNSPEC_GOTREAD 4)
-   (CRIS_UNSPEC_PLTGOTREAD 5)])
+   (CRIS_UNSPEC_PLTGOTREAD 5)
+   (CRIS_UNSPEC_SWAP_BITS 6)])
 
 ;; Register numbers.
 (define_constants
@@ -2678,6 +2679,31 @@
   "swapwb %0"
   [(set_attr "slottable" "yes")])
 
+;; This instruction swaps all bits in a register.
+;; That means that the most significant bit is put in the place
+;; of the least significant bit, and so on.
+
+(define_insn "cris_swap_bits"
+  [(set (match_operand:SI 0 "register_operand" "=r")
+	(unspec:SI [(match_operand:SI 1 "register_operand" "0")]
+		   CRIS_UNSPEC_SWAP_BITS))]
+  "TARGET_HAS_SWAP"
+  "swapwbr %0"
+  [(set_attr "slottable" "yes")])
+
+;; Implement ctz using two instructions, one for bit swap and one for clz.
+;; Defines a scratch register to avoid clobbering input.
+
+(define_expand "ctzsi2"
+  [(set (match_dup 2)
+	(match_operand:SI 1 "register_operand"))
+   (set (match_dup 2)
+	(unspec:SI [(match_dup 2)] CRIS_UNSPEC_SWAP_BITS))
+   (set (match_operand:SI 0 "register_operand")
+	(clz:SI (match_dup 2)))]
+  "TARGET_HAS_LZ && TARGET_HAS_SWAP"
+  "operands[2] = gen_reg_rtx (SImode);")
+
 ;; Bound-insn.  Defined to be the same as an unsigned minimum, which is an
 ;; operation supported by gcc.  Used in casesi, but used now and then in
 ;; normal code too.
diff --git a/gcc/longlong.h b/gcc/longlong.h
index edb9bfd5f35..8350fbc2b45 100644
--- a/gcc/longlong.h
+++ b/gcc/longlong.h
@@ -228,6 +228,9 @@ UDItype __umulsidi3 (USItype, USItype);
 
 #if defined (__CRIS__) && __CRIS_arch_version >= 3
 #define count_leading_zeros(COUNT, X) ((COUNT) = __builtin_clz (X))
+#if __CRIS_arch_version >= 8
+#define count_trailing_zeros(COUNT, X) ((COUNT) = __builtin_ctz (X))
+#endif
 #endif /* __CRIS__ */
 
 #if defined (__hppa) && W_TYPE_SIZE == 32