diff --git a/src/gallium/drivers/radeonsi/si_shader_nir.c b/src/gallium/drivers/radeonsi/si_shader_nir.c
index 7e455ac2826..5c27d4a9e0f 100644
--- a/src/gallium/drivers/radeonsi/si_shader_nir.c
+++ b/src/gallium/drivers/radeonsi/si_shader_nir.c
@@ -266,6 +266,12 @@ static void si_lower_nir(struct si_screen *sscreen, struct nir_shader *nir)
    NIR_PASS_V(nir, nir_lower_system_values);
    NIR_PASS_V(nir, nir_lower_compute_system_values, NULL);
 
+   /* si_nir_kill_outputs and ac_nir_optimize_outputs require outputs to be scalar. */
+   if (nir->info.stage == MESA_SHADER_VERTEX ||
+       nir->info.stage == MESA_SHADER_TESS_EVAL ||
+       nir->info.stage == MESA_SHADER_GEOMETRY)
+      NIR_PASS_V(nir, nir_lower_io_to_scalar, nir_var_shader_out);
+
    if (nir->info.stage == MESA_SHADER_COMPUTE) {
       if (nir->info.cs.derivative_group == DERIVATIVE_GROUP_QUADS) {
          /* If we are shuffling local_invocation_id for quad derivatives, we