diff --git a/codecs/lpc10/invert.c b/codecs/lpc10/invert.c
index 912117f9c5e60d80c4a77b8c2b72afb28a4726b3..03c27e20d134808e2922be2598e229dc77a5ef43 100644
--- a/codecs/lpc10/invert.c
+++ b/codecs/lpc10/invert.c
@@ -93,7 +93,8 @@ extern int invert_(integer *order, real *phi, real *psi, real *rc);
 /* Subroutine */ int invert_(integer *order, real *phi, real *psi, real *rc)
 {
     /* System generated locals */
-    integer phi_dim1, phi_offset, i__1, i__2, i__3;
+    unsigned i__2;
+    integer phi_dim1, phi_offset, i__1, i__3;
     real r__1, r__2;
 
     /* Local variables */