diff --git a/src/imagination/pco/pco_opt.c b/src/imagination/pco/pco_opt.c
index e08863db3d2..26caf8b9953 100644
--- a/src/imagination/pco/pco_opt.c
+++ b/src/imagination/pco/pco_opt.c
@@ -258,6 +258,9 @@ static inline bool try_back_prop_instr(struct pco_use *uses, pco_instr *instr)
 
    pco_ref *pdest_from = &use->instr->dest[0];
 
+   if (pco_ref_is_idx_reg(*pdest_from))
+      return false;
+
    if (pco_ref_is_reg(*pdest_from) &&
        pco_ref_get_reg_class(*pdest_from) == PCO_REG_CLASS_PIXOUT) {
       return false;