diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8255b41231a..690b114fa51 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,8 @@
 2011-01-12  Richard Henderson  <rth@redhat.com>
 
+	* config/mn10300/mn10300.md (UNSPEC_BSCH): New.
+	(clzsi2, *bsch): New patterns.
+
 	* config/mn10300/mn10300.md (INT): New mode iterator.
 	(*mov<INT>_clr): New pattern, and peep2 to generate it.
 
diff --git a/gcc/config/mn10300/mn10300.md b/gcc/config/mn10300/mn10300.md
index ecabaf950c9..8ae52c904e1 100644
--- a/gcc/config/mn10300/mn10300.md
+++ b/gcc/config/mn10300/mn10300.md
@@ -36,6 +36,8 @@
   (UNSPEC_GOTOFF	3)
   (UNSPEC_PLT		4)
   (UNSPEC_GOTSYM_OFF	5)
+
+  (UNSPEC_BSCH		7)
 ])
 
 (include "predicates.md")
@@ -2352,6 +2354,28 @@
 				       (const_int 11) (const_int 22)))]
 )
 
+;; ----------------------------------------------------------------------
+;; MISCELANEOUS
+;; ----------------------------------------------------------------------
+
+(define_expand "clzsi2"
+  [(parallel [(set (match_operand:SI 0 "register_operand" "")
+		   (unspec:SI [(match_operand:SI 1 "register_operand" "")
+			       (const_int 0)] UNSPEC_BSCH))
+	      (clobber (reg:CC CC_REG))])]
+  "TARGET_AM33"
+)
+
+(define_insn "*bsch"
+  [(set (match_operand:SI 0 "register_operand" "=r")
+	(unspec:SI [(match_operand:SI 1 "register_operand" "r")
+		    (match_operand:SI 2 "nonmemory_operand" "0")]
+		   UNSPEC_BSCH))
+   (clobber (reg:CC CC_REG))]
+  "TARGET_AM33"
+  "bsch %1,%0"
+)
+
 ;; ----------------------------------------------------------------------
 ;; FP INSTRUCTIONS
 ;; ----------------------------------------------------------------------