[Mesa-dev] [PATCH 150/133] nir/lower_variables: Use a for loop for get_deref_node

[Connor Abbott]

Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>

On Tue, Jan 6, 2015 at 7:34 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> ---
>  src/glsl/nir/nir_lower_variables.c | 111 +++++++++++++++++--------------------
>  1 file changed, 50 insertions(+), 61 deletions(-)
>
> diff --git a/src/glsl/nir/nir_lower_variables.c b/src/glsl/nir/nir_lower_variables.c
> index 84cf85f..6c3e6cc 100644
> --- a/src/glsl/nir/nir_lower_variables.c
> +++ b/src/glsl/nir/nir_lower_variables.c
> @@ -192,81 +192,73 @@ get_deref_node(nir_deref_var *deref, bool add_to_leaves,
>                 struct lower_variables_state *state)
>  {
>     bool is_leaf = true;
> -   struct deref_node *parent = NULL;
> -   nir_deref *tail = &deref->deref;
> -   while (tail) {
> -      struct deref_node *node;
>
> -      switch (tail->deref_type) {
> -      case nir_deref_type_var: {
> -         assert(tail == &deref->deref);
> -         assert(parent == NULL);
> +   struct deref_node *node;
>
> -         uint32_t var_hash = _mesa_hash_pointer(deref->var);
> -         struct hash_entry *entry =
> -            _mesa_hash_table_search(state->deref_var_nodes,
> -                                    var_hash, deref->var);
> -         if (entry) {
> -            node = entry->data;
> -         } else {
> -            node = deref_node_create(NULL, tail->type, state->dead_ctx);
> -            _mesa_hash_table_insert(state->deref_var_nodes,
> -                                    var_hash, deref->var, node);
> -         }
> -         break;
> -      }
> +   uint32_t var_hash = _mesa_hash_pointer(deref->var);
> +   struct hash_entry *var_entry =
> +      _mesa_hash_table_search(state->deref_var_nodes, var_hash, deref->var);
>
> -      case nir_deref_type_struct: {
> -         assert(parent != NULL);
> +   if (var_entry) {
> +      node = var_entry->data;
> +   } else {
> +      node = deref_node_create(NULL, deref->deref.type, state->dead_ctx);
> +      _mesa_hash_table_insert(state->deref_var_nodes,
> +                              var_hash, deref->var, node);
> +   }
>
> +   for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {
> +      switch (tail->deref_type) {
> +      case nir_deref_type_struct: {
>           nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
> -         assert(deref_struct->index < type_get_length(parent->type));
> -         if (parent->children[deref_struct->index]) {
> -            node = parent->children[deref_struct->index];
> -         } else {
> -            node = deref_node_create(parent, tail->type, state->dead_ctx);
> -            parent->children[deref_struct->index] = node;
> -         }
> +
> +         assert(deref_struct->index < type_get_length(node->type));
> +
> +         if (node->children[deref_struct->index] == NULL)
> +            node->children[deref_struct->index] =
> +               deref_node_create(node, tail->type, state->dead_ctx);
> +
> +         node = node->children[deref_struct->index];
>           break;
>        }
>
>        case nir_deref_type_array: {
> -         assert(parent != NULL);
> -
>           nir_deref_array *arr = nir_deref_as_array(tail);
> +
>           switch (arr->deref_array_type) {
>           case nir_deref_array_type_direct:
> -            if (arr->base_offset >= type_get_length(parent->type)) {
> -               /* This is possible if a loop unrolls and generates an
> -                * out-of-bounds offset.  We need to handle this at least
> -                * somewhat gracefully.
> -                */
> +            /* This is possible if a loop unrolls and generates an
> +             * out-of-bounds offset.  We need to handle this at least
> +             * somewhat gracefully.
> +             */
> +            if (arr->base_offset >= type_get_length(node->type))
>                 return NULL;
> -            } else if (parent->children[arr->base_offset]) {
> -               node = parent->children[arr->base_offset];
> -            } else {
> -               node = deref_node_create(parent, tail->type, state->dead_ctx);
> -               parent->children[arr->base_offset] = node;
> -            }
> +
> +            if (node->children[arr->base_offset] == NULL)
> +               node->children[arr->base_offset] =
> +                  deref_node_create(node, tail->type, state->dead_ctx);
> +
> +            node = node->children[arr->base_offset];
>              break;
> +
>           case nir_deref_array_type_indirect:
> -            if (parent->indirect) {
> -               node = parent->indirect;
> -            } else {
> -               node = deref_node_create(parent, tail->type, state->dead_ctx);
> -               parent->indirect = node;
> -            }
> +            if (node->indirect == NULL)
> +               node->indirect = deref_node_create(node, tail->type,
> +                                                  state->dead_ctx);
> +
> +            node = node->indirect;
>              is_leaf = false;
>              break;
> +
>           case nir_deref_array_type_wildcard:
> -            if (parent->wildcard) {
> -               node = parent->wildcard;
> -            } else {
> -               node = deref_node_create(parent, tail->type, state->dead_ctx);
> -               parent->wildcard = node;
> -            }
> +            if (node->wildcard == NULL)
> +               node->wildcard = deref_node_create(node, tail->type,
> +                                                  state->dead_ctx);
> +
> +            node = node->wildcard;
>              is_leaf = false;
>              break;
> +
>           default:
>              unreachable("Invalid array deref type");
>           }
> @@ -275,18 +267,15 @@ get_deref_node(nir_deref_var *deref, bool add_to_leaves,
>        default:
>           unreachable("Invalid deref type");
>        }
> -
> -      parent = node;
> -      tail = tail->child;
>     }
>
> -   assert(parent);
> +   assert(node);
>
>     if (is_leaf && add_to_leaves)
>        _mesa_hash_table_insert(state->deref_leaves,
> -                              hash_deref(deref), deref, parent);
> +                              hash_deref(deref), deref, node);
>
> -   return parent;
> +   return node;
>  }
>
>  /* \sa foreach_deref_node_match */
> --
> 2.2.0
>
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