diff --git a/src/compiler/nir/nir_lower_io_to_vector.c b/src/compiler/nir/nir_lower_io_to_vector.c
index 27913b507e9..f7e589022f1 100644
--- a/src/compiler/nir/nir_lower_io_to_vector.c
+++ b/src/compiler/nir/nir_lower_io_to_vector.c
@@ -24,6 +24,7 @@
 #include "nir.h"
 #include "nir_builder.h"
 #include "nir_deref.h"
+#include "util/u_dynarray.h"
 
 /** @file nir_lower_io_to_vector.c
  *
@@ -210,7 +211,8 @@ get_flat_type(const nir_shader *shader, nir_variable *old_vars[MAX_SLOTS][4],
 static bool
 create_new_io_vars(nir_shader *shader, nir_variable_mode mode,
                    nir_variable *new_vars[MAX_SLOTS][4],
-                   bool flat_vars[MAX_SLOTS])
+                   bool flat_vars[MAX_SLOTS],
+                   struct util_dynarray *demote_vars)
 {
    nir_variable *old_vars[MAX_SLOTS][4] = {{0}};
 
@@ -277,7 +279,10 @@ create_new_io_vars(nir_shader *shader, nir_variable_mode mode,
          nir_shader_add_variable(shader, var);
          for (unsigned i = first; i < frac; i++) {
             new_vars[loc][i] = var;
-            old_vars[loc][i] = NULL;
+            if (old_vars[loc][i]) {
+               util_dynarray_append(demote_vars, nir_variable *, old_vars[loc][i]);
+               old_vars[loc][i] = NULL;
+            }
          }
 
          old_vars[loc][first] = var;
@@ -411,6 +416,9 @@ nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
 
    nir_metadata_require(impl, nir_metadata_dominance);
 
+   struct util_dynarray demote_vars;
+   util_dynarray_init(&demote_vars, NULL);
+
    nir_shader *shader = impl->function->shader;
    nir_variable *new_inputs[MAX_SLOTS][4] = {{0}};
    nir_variable *new_outputs[MAX_SLOTS][4] = {{0}};
@@ -425,7 +433,7 @@ nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
        * so we don't bother doing extra non-work.
        */
       if (!create_new_io_vars(shader, nir_var_shader_in,
-                              new_inputs, flat_inputs))
+                              new_inputs, flat_inputs, &demote_vars))
          modes &= ~nir_var_shader_in;
    }
 
@@ -434,7 +442,7 @@ nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
        * so we don't bother doing extra non-work.
        */
       if (!create_new_io_vars(shader, nir_var_shader_out,
-                              new_outputs, flat_outputs))
+                              new_outputs, flat_outputs, &demote_vars))
          modes &= ~nir_var_shader_out;
    }
 
@@ -585,6 +593,15 @@ nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes)
       }
    }
 
+   /* Demote the old var to a global, so that things like
+    * nir_lower_io_to_temporaries() don't trigger on it.
+    */
+   util_dynarray_foreach(&demote_vars, nir_variable *, varp) {
+      (*varp)->data.mode = nir_var_shader_temp;
+   }
+   nir_fixup_deref_modes(b.shader);
+   util_dynarray_fini(&demote_vars);
+
    if (progress) {
       nir_metadata_preserve(impl, nir_metadata_block_index |
                                   nir_metadata_dominance);