Index: sys/sys/tree.h
===================================================================
--- sys/sys/tree.h
+++ sys/sys/tree.h
@@ -380,7 +380,6 @@
 } while (/*CONSTCOND*/ 0)
 
 #define RB_ROTATE_LEFT(head, elm, tmp, field) do {			\
-	(tmp) = RB_RIGHT(elm, field);					\
 	if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field)) != NULL) {	\
 		RB_SET_PARENT(RB_RIGHT(elm, field), elm, field);	\
 	}								\
@@ -392,7 +391,6 @@
 } while (/*CONSTCOND*/ 0)
 
 #define RB_ROTATE_RIGHT(head, elm, tmp, field) do {			\
-	(tmp) = RB_LEFT(elm, field);					\
 	if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field)) != NULL) {	\
 		RB_SET_PARENT(RB_LEFT(elm, field), elm, field);		\
 	}								\
@@ -465,19 +463,18 @@
 name##_RB_INSERT_COLOR(struct name *head, struct type *elm)		\
 {									\
 	struct type *child, *parent;					\
-	while ((parent = RB_PARENT(elm, field)) != NULL) {		\
+	for (; (parent = RB_PARENT(elm, field)) != NULL; elm = parent) {\
 		if (RB_LEFT(parent, field) == elm) {			\
 			if (RB_RED_LEFT(parent, field)) {		\
 				RB_FLIP_LEFT(parent, field);		\
-				return;					\
+				break;					\
 			}						\
 			RB_FLIP_RIGHT(parent, field);			\
-			if (RB_RED_RIGHT(parent, field)) {		\
-				elm = parent;				\
+			if (RB_RED_RIGHT(parent, field))		\
 				continue;				\
-			}						\
 			if (!RB_RED_RIGHT(elm, field)) {		\
 				RB_FLIP_LEFT(elm, field);		\
+				child = RB_RIGHT(elm, field);		\
 				RB_ROTATE_LEFT(head, elm, child, field);\
 				if (RB_RED_LEFT(child, field))		\
 					RB_FLIP_RIGHT(elm, field);	\
@@ -489,15 +486,14 @@
 		} else {						\
 			if (RB_RED_RIGHT(parent, field)) {		\
 				RB_FLIP_RIGHT(parent, field);		\
-				return;					\
+				break;					\
 			}						\
 			RB_FLIP_LEFT(parent, field);			\
-			if (RB_RED_LEFT(parent, field)) {		\
-				elm = parent;				\
+			if (RB_RED_LEFT(parent, field))			\
 				continue;				\
-			}						\
 			if (!RB_RED_LEFT(elm, field)) {			\
 				RB_FLIP_RIGHT(elm, field);		\
+				child = RB_LEFT(elm, field);		\
 				RB_ROTATE_RIGHT(head, elm, child, field);\
 				if (RB_RED_RIGHT(child, field))		\
 					RB_FLIP_LEFT(elm, field);	\
@@ -517,79 +513,77 @@
 name##_RB_REMOVE_COLOR(struct name *head,				\
     struct type *parent, struct type *elm)				\
 {									\
-	struct type *sib;						\
+	struct type *child;						\
 	if (RB_LEFT(parent, field) == elm &&				\
 	    RB_RIGHT(parent, field) == elm) {				\
 		RB_BITS(parent, field) &= ~RB_RED_MASK;			\
 		elm = parent;						\
-		parent = RB_PARENT(elm, field);				\
-		if (parent == NULL)					\
+		if ((parent = RB_PARENT(elm, field)) == NULL)		\
 			return;						\
 	}								\
 	do  {								\
 		if (RB_LEFT(parent, field) == elm) {			\
 			if (!RB_RED_LEFT(parent, field)) {		\
 				RB_FLIP_LEFT(parent, field);		\
-				return;					\
+				break;					\
 			}						\
 			if (RB_RED_RIGHT(parent, field)) {		\
 				RB_FLIP_RIGHT(parent, field);		\
-				elm = parent;				\
 				continue;				\
 			}						\
-			sib = RB_RIGHT(parent, field);			\
-			if ((~RB_BITS(sib, field) & RB_RED_MASK) == 0) {\
-				RB_BITS(sib, field) &= ~RB_RED_MASK;	\
-				elm = parent;				\
+			elm = RB_RIGHT(parent, field);			\
+			if ((~RB_BITS(elm, field) & RB_RED_MASK) == 0) {\
+				RB_BITS(elm, field) &= ~RB_RED_MASK;	\
 				continue;				\
 			}						\
-			RB_FLIP_RIGHT(sib, field);			\
-			if (RB_RED_LEFT(sib, field))			\
+			RB_FLIP_RIGHT(elm, field);			\
+			if (RB_RED_LEFT(elm, field))			\
 				RB_FLIP_LEFT(parent, field);		\
-			else if (!RB_RED_RIGHT(sib, field)) {		\
+			else if (!RB_RED_RIGHT(elm, field)) {		\
 				RB_FLIP_LEFT(parent, field);		\
-				RB_ROTATE_RIGHT(head, sib, elm, field);	\
-				if (RB_RED_RIGHT(elm, field))		\
-					RB_FLIP_LEFT(sib, field);	\
-				if (RB_RED_LEFT(elm, field))		\
+				child = RB_LEFT(elm, field);		\
+				RB_ROTATE_RIGHT(head, elm, child, field); \
+				if (RB_RED_RIGHT(child, field))		\
+					RB_FLIP_LEFT(elm, field);	\
+				if (RB_RED_LEFT(child, field))		\
 					RB_FLIP_RIGHT(parent, field);	\
-				RB_BITS(elm, field) |= RB_RED_MASK;	\
-				sib = elm;				\
+				RB_BITS(child, field) |= RB_RED_MASK;	\
+				elm = child;				\
 			}						\
-			RB_ROTATE_LEFT(head, parent, sib, field);	\
+			RB_ROTATE_LEFT(head, parent, elm, field);	\
 		} else {						\
 			if (!RB_RED_RIGHT(parent, field)) {		\
 				RB_FLIP_RIGHT(parent, field);		\
-				return;					\
+				break;					\
 			}						\
 			if (RB_RED_LEFT(parent, field)) {		\
 				RB_FLIP_LEFT(parent, field);		\
-				elm = parent;				\
 				continue;				\
 			}						\
-			sib = RB_LEFT(parent, field);			\
-			if ((~RB_BITS(sib, field) & RB_RED_MASK) == 0) {\
-				RB_BITS(sib, field) &= ~RB_RED_MASK;	\
-				elm = parent;				\
+			elm = RB_LEFT(parent, field);			\
+			if ((~RB_BITS(elm, field) & RB_RED_MASK) == 0) {\
+				RB_BITS(elm, field) &= ~RB_RED_MASK;	\
 				continue;				\
 			}						\
-			RB_FLIP_LEFT(sib, field);			\
-			if (RB_RED_RIGHT(sib, field))			\
+			RB_FLIP_LEFT(elm, field);			\
+			if (RB_RED_RIGHT(elm, field))			\
 				RB_FLIP_RIGHT(parent, field);		\
-			else if (!RB_RED_LEFT(sib, field)) {		\
+			else if (!RB_RED_LEFT(elm, field)) {		\
 				RB_FLIP_RIGHT(parent, field);		\
-				RB_ROTATE_LEFT(head, sib, elm, field);	\
-				if (RB_RED_LEFT(elm, field))		\
-					RB_FLIP_RIGHT(sib, field);	\
-				if (RB_RED_RIGHT(elm, field))		\
+				child = RB_RIGHT(elm, field);		\
+				RB_ROTATE_LEFT(head, elm, child, field); \
+				if (RB_RED_LEFT(child, field))		\
+					RB_FLIP_RIGHT(elm, field);	\
+				if (RB_RED_RIGHT(child, field))		\
 					RB_FLIP_LEFT(parent, field);	\
-				RB_BITS(elm, field) |= RB_RED_MASK;	\
-				sib = elm;				\
+				RB_BITS(child, field) |= RB_RED_MASK;	\
+				elm = child;				\
 			}						\
-			RB_ROTATE_RIGHT(head, parent, sib, field);	\
+			RB_ROTATE_RIGHT(head, parent, elm, field);	\
 		}							\
 		break;							\
-	} while ((parent = RB_PARENT(elm, field)) != NULL);		\
+	} while (elm = parent,						\
+	    (parent = RB_PARENT(elm, field)) != NULL);			\
 }
 
 #define RB_GENERATE_REMOVE(name, type, field, attr)			\