[Mesa-dev] [PATCH 02/20] nir: clarify some nit_loop_info member names

Jason Ekstrand jason at jlekstrand.net
Fri Dec 7 23:10:36 UTC 2018


Replacing min with max without changing any real code always looks a biit
weird but it does make sense. :-)

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>

On Thu, Dec 6, 2018 at 9:08 PM Timothy Arceri <tarceri at itsqueeze.com> wrote:

> Following commits will introduce additional fields such as
> guessed_trip_count. Renaming these will help avoid confusion
> as our unrolling feature set grows.
>
> Reviewed-by: Thomas Helland <thomashelland90 at gmail.com>
> ---
>  src/compiler/nir/nir.h                 |  8 +++++---
>  src/compiler/nir/nir_loop_analyze.c    | 14 +++++++-------
>  src/compiler/nir/nir_opt_loop_unroll.c | 14 +++++++-------
>  3 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index db935c8496..ce4a81fbe1 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -1886,9 +1886,11 @@ typedef struct {
>     /* Number of instructions in the loop */
>     unsigned num_instructions;
>
> -   /* How many times the loop is run (if known) */
> -   unsigned trip_count;
> -   bool is_trip_count_known;
> +   /* Maximum number of times the loop is run (if known) */
> +   unsigned max_trip_count;
> +
> +   /* Do we know the exact number of times the loop will be run */
> +   bool exact_trip_count_known;
>
>     /* Unroll the loop regardless of its size */
>     bool force_unroll;
> diff --git a/src/compiler/nir/nir_loop_analyze.c
> b/src/compiler/nir/nir_loop_analyze.c
> index c779383b36..700d1fe552 100644
> --- a/src/compiler/nir/nir_loop_analyze.c
> +++ b/src/compiler/nir/nir_loop_analyze.c
> @@ -527,7 +527,7 @@ find_trip_count(loop_info_state *state)
>  {
>     bool trip_count_known = true;
>     nir_loop_terminator *limiting_terminator = NULL;
> -   int min_trip_count = -1;
> +   int max_trip_count = -1;
>
>     list_for_each_entry(nir_loop_terminator, terminator,
>                         &state->loop->info->loop_terminator_list,
> @@ -606,8 +606,8 @@ find_trip_count(loop_info_state *state)
>            * iterations than previously (we have identified a more limiting
>            * terminator) set the trip count and limiting terminator.
>            */
> -         if (min_trip_count == -1 || iterations < min_trip_count) {
> -            min_trip_count = iterations;
> +         if (max_trip_count == -1 || iterations < max_trip_count) {
> +            max_trip_count = iterations;
>              limiting_terminator = terminator;
>           }
>           break;
> @@ -617,9 +617,9 @@ find_trip_count(loop_info_state *state)
>        }
>     }
>
> -   state->loop->info->is_trip_count_known = trip_count_known;
> -   if (min_trip_count > -1)
> -      state->loop->info->trip_count = min_trip_count;
> +   state->loop->info->exact_trip_count_known = trip_count_known;
> +   if (max_trip_count > -1)
> +      state->loop->info->max_trip_count = max_trip_count;
>     state->loop->info->limiting_terminator = limiting_terminator;
>  }
>
> @@ -639,7 +639,7 @@ force_unroll_array_access(loop_info_state *state,
> nir_deref_instr *deref)
>        nir_deref_instr *parent = nir_deref_instr_parent(d);
>        assert(glsl_type_is_array(parent->type) ||
>               glsl_type_is_matrix(parent->type));
> -      if (glsl_get_length(parent->type) == state->loop->info->trip_count)
> +      if (glsl_get_length(parent->type) ==
> state->loop->info->max_trip_count)
>           return true;
>
>        if (deref->mode & state->indirect_mask)
> diff --git a/src/compiler/nir/nir_opt_loop_unroll.c
> b/src/compiler/nir/nir_opt_loop_unroll.c
> index ea2012e292..0e9966320b 100644
> --- a/src/compiler/nir/nir_opt_loop_unroll.c
> +++ b/src/compiler/nir/nir_opt_loop_unroll.c
> @@ -181,7 +181,7 @@ simple_unroll(nir_loop *loop)
>     nir_cf_list unrolled_lp_body;
>
>     /* Clone loop header and append to the loop body */
> -   for (unsigned i = 0; i < loop->info->trip_count; i++) {
> +   for (unsigned i = 0; i < loop->info->max_trip_count; i++) {
>        /* Clone loop body */
>        nir_cf_list_clone(&unrolled_lp_body, &loop_body,
> loop->cf_node.parent,
>                          remap_table);
> @@ -340,7 +340,7 @@ complex_unroll(nir_loop *loop, nir_loop_terminator
> *unlimit_term,
>         * trip count == 1 we execute the code above the break twice and the
>         * code below it once so we need clone things twice and so on.
>         */
> -      num_times_to_clone = loop->info->trip_count + 1;
> +      num_times_to_clone = loop->info->max_trip_count + 1;
>     } else {
>        /* Pluck out the loop header */
>        nir_cf_extract(&lp_header, nir_before_block(header_blk),
> @@ -368,7 +368,7 @@ complex_unroll(nir_loop *loop, nir_loop_terminator
> *unlimit_term,
>
>        nir_cf_node_remove(&limiting_term->nif->cf_node);
>
> -      num_times_to_clone = loop->info->trip_count;
> +      num_times_to_clone = loop->info->max_trip_count;
>     }
>
>     /* In the terminator that we have no trip count for move everything
> after
> @@ -568,14 +568,14 @@ is_loop_small_enough_to_unroll(nir_shader *shader,
> nir_loop_info *li)
>  {
>     unsigned max_iter = shader->options->max_unroll_iterations;
>
> -   if (li->trip_count > max_iter)
> +   if (li->max_trip_count > max_iter)
>        return false;
>
>     if (li->force_unroll)
>        return true;
>
>     bool loop_not_too_large =
> -      li->num_instructions * li->trip_count <= max_iter *
> LOOP_UNROLL_LIMIT;
> +      li->num_instructions * li->max_trip_count <= max_iter *
> LOOP_UNROLL_LIMIT;
>
>     return loop_not_too_large;
>  }
> @@ -641,7 +641,7 @@ process_loops(nir_shader *sh, nir_cf_node *cf_node,
> bool *has_nested_loop_out)
>        if (!is_loop_small_enough_to_unroll(sh, loop->info))
>           goto exit;
>
> -      if (loop->info->is_trip_count_known) {
> +      if (loop->info->exact_trip_count_known) {
>           simple_unroll(loop);
>           progress = true;
>        } else {
> @@ -665,7 +665,7 @@ process_loops(nir_shader *sh, nir_cf_node *cf_node,
> bool *has_nested_loop_out)
>               * limiting terminator just do a simple unroll as the second
>               * terminator can never be reached.
>               */
> -            if (loop->info->trip_count == 0 && !limiting_term_second) {
> +            if (loop->info->max_trip_count == 0 && !limiting_term_second)
> {
>                 simple_unroll(loop);
>              } else {
>                 complex_unroll(loop, terminator, limiting_term_second);
> --
> 2.19.2
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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