diff --git a/src/test/matmul.s b/src/test/matmul.s
index 18ddc59b..d0c6a146 100644
--- a/src/test/matmul.s
+++ b/src/test/matmul.s
@@ -70,7 +70,7 @@ iloop:  ld %r7, %r11, #0;
   @p0 ? jmpi cloop;
 
         addi %r9, %r9, #1;
-        sub %r7, %r9, %r4;
+        sub %r7, %r9, %r14;
         rtop @p0, %r7;
   @p0 ? jmpi rloop;