nir/opt_uniform_atomics: require block index metadata

is_atomic_already_optimized() uses this.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30518>

src/compiler/nir/nir_opt_uniform_atomics.c

@@ -369,6 +369,8 @@ nir_opt_uniform_atomics(nir_shader *shader)
       return false;
 
    nir_foreach_function_impl(impl, shader) {
+      nir_metadata_require(impl, nir_metadata_block_index);
+
       if (opt_uniform_atomics(impl)) {
          progress = true;
          nir_metadata_preserve(impl, nir_metadata_none);