<div dir="ltr"><div>Replacing min with max without changing any real code always looks a biit weird but it does make sense. :-)</div><div> </div><div>Reviewed-by: Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> </div></div> <div class="gmail_quote"><div dir="ltr">On Thu, Dec 6, 2018 at 9:08 PM Timothy Arceri <<a href="mailto:tarceri@itsqueeze.com">tarceri@itsqueeze.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">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 <<a href="mailto:thomashelland90@gmail.com" target="_blank">thomashelland90@gmail.com</a>> --- 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 <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div>