[Mesa-dev] [PATCH 3/3] nir: simplify node matching code when lowering to SSA
Jason Ekstrand
jason at jlekstrand.net
Wed Apr 11 05:15:45 UTC 2018
On Tue, Apr 10, 2018 at 12:52 PM, Caio Marcelo de Oliveira Filho <
caio.oliveira at intel.com> wrote:
> The matching code doesn't make real use of the return value. The main
> function return value is ignored, and while the worker function
> propagate its return value, the actual callback never returns false.
>
When I wrote this, I don't think I realized it was only going to have the
one use. I was mostly following the pattern we'd used for all the other
foreach functions in NIR. That said, I think this is better.
> ---
> src/compiler/nir/nir_lower_vars_to_ssa.c | 73 +++++++++++-------------
> 1 file changed, 32 insertions(+), 41 deletions(-)
>
> diff --git a/src/compiler/nir/nir_lower_vars_to_ssa.c
> b/src/compiler/nir/nir_lower_vars_to_ssa.c
> index 4c41dd69cf..f84ad067ee 100644
> --- a/src/compiler/nir/nir_lower_vars_to_ssa.c
> +++ b/src/compiler/nir/nir_lower_vars_to_ssa.c
> @@ -217,45 +217,40 @@ get_deref_node(nir_deref_var *deref, struct
> lower_variables_state *state)
> }
>
> /* \sa foreach_deref_node_match */
> -static bool
> +static void
> foreach_deref_node_worker(struct deref_node *node, nir_deref *deref,
> - bool (* cb)(struct deref_node *node,
> + void (* cb)(struct deref_node *node,
> struct lower_variables_state
> *state),
> struct lower_variables_state *state)
> {
> if (deref->child == NULL) {
> - return cb(node, state);
> - } else {
> - switch (deref->child->deref_type) {
> - case nir_deref_type_array: {
> - nir_deref_array *arr = nir_deref_as_array(deref->child);
> - assert(arr->deref_array_type == nir_deref_array_type_direct);
> - if (node->children[arr->base_offset] &&
> - !foreach_deref_node_worker(node->children[arr->base_offset],
> - deref->child, cb, state))
> - return false;
> -
> - if (node->wildcard &&
> - !foreach_deref_node_worker(node->wildcard,
> - deref->child, cb, state))
> - return false;
> -
> - return true;
> - }
> + cb(node, state);
> + return;
> + }
>
> - case nir_deref_type_struct: {
> - nir_deref_struct *str = nir_deref_as_struct(deref->child);
> - if (node->children[str->index] &&
> - !foreach_deref_node_worker(node->children[str->index],
> - deref->child, cb, state))
> - return false;
> + switch (deref->child->deref_type) {
> + case nir_deref_type_array: {
> + nir_deref_array *arr = nir_deref_as_array(deref->child);
> + assert(arr->deref_array_type == nir_deref_array_type_direct);
> +
> + if (node->children[arr->base_offset])
> + foreach_deref_node_worker(node->children[arr->base_offset],
> + deref->child, cb, state);
>
When a block contains multiple lines, we use { } regardless of whether or
not it's just a single statement.
> + if (node->wildcard)
> + foreach_deref_node_worker(node->wildcard, deref->child, cb,
> state);
> + break;
> + }
>
> - return true;
> - }
> + case nir_deref_type_struct: {
> + nir_deref_struct *str = nir_deref_as_struct(deref->child);
> + if (node->children[str->index])
> + foreach_deref_node_worker(node->children[str->index],
> + deref->child, cb, state);
>
Same here.
> + break;
> + }
>
> - default:
> - unreachable("Invalid deref child type");
> - }
> + default:
> + unreachable("Invalid deref child type");
> }
> }
>
> @@ -271,9 +266,9 @@ foreach_deref_node_worker(struct deref_node *node,
> nir_deref *deref,
> * The given deref must be a full-length and fully qualified (no wildcards
> * or indirects) deref chain.
> */
> -static bool
> +static void
> foreach_deref_node_match(nir_deref_var *deref,
> - bool (* cb)(struct deref_node *node,
> + void (* cb)(struct deref_node *node,
> struct lower_variables_state *state),
> struct lower_variables_state *state)
> {
> @@ -281,10 +276,8 @@ foreach_deref_node_match(nir_deref_var *deref,
> var_deref.deref.child = NULL;
> struct deref_node *node = get_deref_node(&var_deref, state);
>
> - if (node == NULL)
> - return false;
>
I think I still like the early return a tad bit better. I'm not going to
be insistent though.
> -
> - return foreach_deref_node_worker(node, &deref->deref, cb, state);
> + if (node)
> + foreach_deref_node_worker(node, &deref->deref, cb, state);
> }
>
> /* \sa deref_may_be_aliased */
> @@ -440,12 +433,12 @@ register_variable_uses_block(nir_block *block,
> /* Walks over all of the copy instructions to or from the given deref_node
> * and lowers them to load/store intrinsics.
> */
> -static bool
> +static void
> lower_copies_to_load_store(struct deref_node *node,
> struct lower_variables_state *state)
> {
> if (!node->copies)
> - return true;
> + return;
>
> struct set_entry *copy_entry;
> set_foreach(node->copies, copy_entry) {
> @@ -470,8 +463,6 @@ lower_copies_to_load_store(struct deref_node *node,
> }
>
> node->copies = NULL;
> -
> - return true;
> }
>
> /* Performs variable renaming
> --
> 2.17.0
>
> _______________________________________________
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> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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