nouveau: switch to nir_metadata_divergence

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30814>

src/nouveau/compiler/nak_nir.c

@@ -792,7 +792,7 @@ nak_nir_remove_barriers(nir_shader *nir)
    nir->info.uses_control_barrier = false;
 
    return nir_shader_intrinsics_pass(nir, nak_nir_remove_barrier_intrin,
-                                     nir_metadata_control_flow,
+                                     nir_metadata_control_flow | nir_metadata_divergence,
                                      NULL);
 }
 
@@ -1046,7 +1046,6 @@ nak_postprocess_nir(nir_shader *nir,
       OPT(nir, nak_nir_split_64bit_conversions);
 
    bool lcssa_progress = nir_convert_to_lcssa(nir, false, false);
-   nir_divergence_analysis(nir);
 
    if (nak->sm >= 75) {
       if (lcssa_progress) {
@@ -1055,12 +1054,14 @@ nak_postprocess_nir(nir_shader *nir,
       if (OPT(nir, nak_nir_lower_non_uniform_ldcx)) {
          OPT(nir, nir_copy_prop);
          OPT(nir, nir_opt_dce);
-         nir_divergence_analysis(nir);
       }
    }
 
    OPT(nir, nak_nir_remove_barriers);
 
+   /* Call divergence analysis regardless of sm version. */
+   nir_divergence_analysis(nir);
+
    if (nak->sm >= 70) {
       if (nak_should_print_nir()) {
          fprintf(stderr, "Structured NIR for %s shader:\n",
@@ -1077,6 +1078,9 @@ nak_postprocess_nir(nir_shader *nir,
       if (func->impl) {
          nir_index_blocks(func->impl);
          nir_index_ssa_defs(func->impl);
+
+         /* Ensure that divergence information is correct. */
+         assert(func->impl->valid_metadata & nir_metadata_divergence);
       }
    }
 

src/nouveau/compiler/nak_nir_lower_cf.c

@@ -425,6 +425,8 @@ recompute_phi_divergence_impl(nir_function_impl *impl)
          }
       }
    } while(progress);
+
+   impl->valid_metadata |= nir_metadata_divergence;
 }
 
 static bool
@@ -441,7 +443,7 @@ lower_cf_func(nir_function *func)
    nir_function_impl *old_impl = func->impl;
 
    /* We use this in block_is_merge() */
-   nir_metadata_require(old_impl, nir_metadata_dominance);
+   nir_metadata_require(old_impl, nir_metadata_dominance | nir_metadata_divergence);
 
    /* First, we temporarily get rid of SSA.  This will make all our block
     * motion way easier.

src/nouveau/compiler/nak_nir_lower_non_uniform_ldcx.c

@@ -477,7 +477,7 @@ nak_nir_lower_non_uniform_ldcx(nir_shader *nir)
    nir_builder b = nir_builder_create(impl);
 
    /* We use block indices to determine when something is a predecessor */
-   nir_metadata_require(impl, nir_metadata_block_index);
+   nir_metadata_require(impl, nir_metadata_block_index | nir_metadata_divergence);
 
    if (lower_cf_list(&b, &impl->body)) {
       nir_metadata_preserve(impl, nir_metadata_none);

src/nouveau/compiler/nak_nir_mark_lcssa_invariants.c

@@ -105,10 +105,12 @@ nak_nir_mark_lcssa_invariants(nir_shader *shader)
 
    nir_foreach_function_impl(impl, shader) {
       nir_builder b = nir_builder_create(impl);
+      nir_metadata_require(impl, nir_metadata_divergence);
 
       if (lower_cf_list(&b, &impl->body)) {
          progress = true;
-         nir_metadata_preserve(impl, nir_metadata_control_flow);
+         nir_metadata_preserve(impl, nir_metadata_control_flow |
+                                     nir_metadata_divergence);
       } else {
          nir_metadata_preserve(impl, nir_metadata_all);
       }