diff --git a/js/src/jstracer.cpp b/js/src/jstracer.cpp
index 2af2f1d5e9ff..a91baf0ae7f0 100644
--- a/js/src/jstracer.cpp
+++ b/js/src/jstracer.cpp
@@ -131,7 +131,7 @@ static const char tagChar[]  = "OIDISIBI";
 #define MAX_GLOBAL_SLOTS 4096
 
 /* Max memory you can allocate in a LIR buffer via a single skip() call. */
-#define MAX_SKIP_BYTES (NJ_PAGE_SIZE - (LIR_FAR_SLOTS + 1) * sizeof(LIns*))
+#define MAX_SKIP_BYTES (NJ_PAGE_SIZE - (LIR_FAR_SLOTS + 1) * sizeof(LIns))
 
 /* Max memory needed to rebuild the interpreter stack when falling off trace. */
 #define MAX_INTERP_STACK_BYTES                                                \
diff --git a/js/src/nanojit/LIR.cpp b/js/src/nanojit/LIR.cpp
index b4f63d5f496d..bc3a8d71094f 100644
--- a/js/src/nanojit/LIR.cpp
+++ b/js/src/nanojit/LIR.cpp
@@ -159,7 +159,7 @@ namespace nanojit
 
 	void LirBufWriter::ensureRoom(uint32_t count)
 	{
-		NanoAssert(count <= NJ_PAGE_SIZE - (LIR_FAR_SLOTS + 1) * sizeof(LIns*));
+		NanoAssert(count <= NJ_PAGE_SIZE - (LIR_FAR_SLOTS + 1) * sizeof(LIns));
 		LInsp before = _buf->next();
 		LInsp after = before+count+LIR_FAR_SLOTS;
 		// transition to the next page?