diff --git a/src/mesa/program/prog_to_nir.c b/src/mesa/program/prog_to_nir.c
index cf5c5b1be2e..5cd073d565e 100644
--- a/src/mesa/program/prog_to_nir.c
+++ b/src/mesa/program/prog_to_nir.c
@@ -916,7 +916,7 @@ setup_registers_and_variables(struct ptn_compile *c)
    }
 
    /* Create output registers and variables. */
-   int max_outputs = util_last_bit(c->prog->info.outputs_written);
+   int max_outputs = util_last_bit64(c->prog->info.outputs_written);
    c->output_regs = rzalloc_array(c, nir_register *, max_outputs);
 
    uint64_t outputs_written = c->prog->info.outputs_written;