diff --git a/src/gallium/drivers/vc4/vc4_opt_constant_folding.c b/src/gallium/drivers/vc4/vc4_opt_constant_folding.c
index 9acbea7bbd3..4d485b2032b 100644
--- a/src/gallium/drivers/vc4/vc4_opt_constant_folding.c
+++ b/src/gallium/drivers/vc4/vc4_opt_constant_folding.c
@@ -80,6 +80,7 @@ constant_fold(struct vc4_compile *c, struct qinst *inst)
         uint32_t result = 0;
         switch (inst->op) {
         case QOP_SHR:
+                assert(nsrc == 2);
                 result = ui[0] >> ui[1];
                 break;