* to keep track of and update phis along the way which gets tricky and
* doesn't add much value over converting to regs.
*
- * The loop may have a continue instruction at the end of the loop which does
+ * The loop may have a jump instruction at the end of the loop which does
* nothing. Once we're out of SSA, we can safely delete it so we don't have
* to deal with it later.
*/
nir_lower_phis_to_regs_block(block_after_loop);
- /* Remove continue if its the last instruction in the loop */
+ /* Remove jump if it's the last instruction in the loop */
nir_instr *last_instr = nir_block_last_instr(nir_loop_last_block(loop));
if (last_instr && last_instr->type == nir_instr_type_jump) {
nir_instr_remove(last_instr);
unsigned num_times_to_clone = loop->info->max_trip_count + 1;
nir_cf_list lp_body;
- nir_cf_node *unroll_loc =
+ UNUSED nir_cf_node *unroll_loc =
complex_unroll_loop_body(loop, terminator, &lp_header, &lp_body,
remap_table, num_times_to_clone);
static bool
wrapper_unroll(nir_loop *loop)
{
- if (!list_empty(&loop->info->loop_terminator_list)) {
+ if (!list_is_empty(&loop->info->loop_terminator_list)) {
/* Unrolling a loop with a large number of exits can result in a
* large inrease in register pressure. For now we just skip
nir_after_block(nir_if_last_else_block(terminator->nif));
}
} else {
- nir_block *blk_after_loop =
- nir_cursor_current_block(nir_after_cf_node(&loop->cf_node));
-
- /* There may still be some single src phis following the loop that
- * have not yet been cleaned up by another pass. Tidy those up
- * before unrolling the loop.
- */
- nir_foreach_instr_safe(instr, blk_after_loop) {
- if (instr->type != nir_instr_type_phi)
- break;
-
- nir_phi_instr *phi = nir_instr_as_phi(instr);
- assert(exec_list_length(&phi->srcs) == 1);
-
- nir_phi_src *phi_src =
- exec_node_data(nir_phi_src, exec_list_get_head(&phi->srcs), node);
-
- nir_ssa_def_rewrite_uses(&phi->dest.ssa, phi_src->src);
- nir_instr_remove(instr);
- }
-
- /* Remove break at end of the loop */
- nir_block *last_loop_blk = nir_loop_last_block(loop);
- nir_instr *break_instr = nir_block_last_instr(last_loop_blk);
- nir_instr_remove(break_instr);
+ loop_prepare_for_unroll(loop);
}
/* Pluck out the loop body. */
if (is_access_out_of_bounds(term, nir_src_as_deref(intrin->src[0]),
trip_count)) {
if (intrin->intrinsic == nir_intrinsic_load_deref) {
- assert(intrin->src[0].is_ssa);
- nir_ssa_def *a_ssa = intrin->src[0].ssa;
nir_ssa_def *undef =
- nir_ssa_undef(&b, intrin->num_components,
- a_ssa->bit_size);
+ nir_ssa_undef(&b, intrin->dest.ssa.num_components,
+ intrin->dest.ssa.bit_size);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
nir_src_for_ssa(undef));
} else {
if (intrin->intrinsic == nir_intrinsic_copy_deref &&
is_access_out_of_bounds(term, nir_src_as_deref(intrin->src[1]),
trip_count)) {
- assert(intrin->src[1].is_ssa);
- nir_ssa_def *a_ssa = intrin->src[1].ssa;
- nir_ssa_def *undef =
- nir_ssa_undef(&b, intrin->num_components, a_ssa->bit_size);
-
- /* Replace the copy with a store of the undefined value */
- b.cursor = nir_before_instr(instr);
- nir_store_deref(&b, nir_src_as_deref(intrin->src[0]), undef, ~0);
nir_instr_remove(instr);
}
}
_mesa_hash_table_destroy(remap_table, NULL);
}
+/*
+ * Returns true if we should unroll the loop, otherwise false.
+ */
static bool
-is_loop_small_enough_to_unroll(nir_shader *shader, nir_loop_info *li)
+check_unrolling_restrictions(nir_shader *shader, nir_loop *loop)
{
- unsigned max_iter = shader->options->max_unroll_iterations;
+ if (loop->control == nir_loop_control_unroll)
+ return true;
+
+ if (loop->control == nir_loop_control_dont_unroll)
+ return false;
+ nir_loop_info *li = loop->info;
+ unsigned max_iter = shader->options->max_unroll_iterations;
unsigned trip_count =
li->max_trip_count ? li->max_trip_count : li->guessed_trip_count;
}
static bool
-process_loops(nir_shader *sh, nir_cf_node *cf_node, bool *has_nested_loop_out)
+process_loops(nir_shader *sh, nir_cf_node *cf_node, bool *has_nested_loop_out,
+ bool *unrolled_this_block);
+
+static bool
+process_loops_in_block(nir_shader *sh, struct exec_list *block,
+ bool *has_nested_loop_out)
+{
+ /* We try to unroll as many loops in one pass as possible.
+ * E.g. we can safely unroll both loops in this block:
+ *
+ * if (...) {
+ * loop {...}
+ * }
+ *
+ * if (...) {
+ * loop {...}
+ * }
+ *
+ * Unrolling one loop doesn't affect the other one.
+ *
+ * On the other hand for block with:
+ *
+ * loop {...}
+ * ...
+ * loop {...}
+ *
+ * It is unsafe to unroll both loops in one pass without taking
+ * complicating precautions, since the structure of the block would
+ * change after unrolling the first loop. So in such a case we leave
+ * the second loop for the next iteration of unrolling to handle.
+ */
+
+ bool progress = false;
+ bool unrolled_this_block = false;
+
+ foreach_list_typed(nir_cf_node, nested_node, node, block) {
+ if (process_loops(sh, nested_node,
+ has_nested_loop_out, &unrolled_this_block)) {
+ progress = true;
+
+ /* If current node is unrolled we could not safely continue
+ * our iteration since we don't know the next node
+ * and it's hard to guarantee that we won't end up unrolling
+ * inner loop of the currently unrolled one, if such exists.
+ */
+ if (unrolled_this_block) {
+ break;
+ }
+ }
+ }
+
+ return progress;
+}
+
+static bool
+process_loops(nir_shader *sh, nir_cf_node *cf_node, bool *has_nested_loop_out,
+ bool *unrolled_this_block)
{
bool progress = false;
bool has_nested_loop = false;
return progress;
case nir_cf_node_if: {
nir_if *if_stmt = nir_cf_node_as_if(cf_node);
- foreach_list_typed_safe(nir_cf_node, nested_node, node, &if_stmt->then_list)
- progress |= process_loops(sh, nested_node, has_nested_loop_out);
- foreach_list_typed_safe(nir_cf_node, nested_node, node, &if_stmt->else_list)
- progress |= process_loops(sh, nested_node, has_nested_loop_out);
+ progress |= process_loops_in_block(sh, &if_stmt->then_list,
+ has_nested_loop_out);
+ progress |= process_loops_in_block(sh, &if_stmt->else_list,
+ has_nested_loop_out);
return progress;
}
case nir_cf_node_loop: {
loop = nir_cf_node_as_loop(cf_node);
- foreach_list_typed_safe(nir_cf_node, nested_node, node, &loop->body)
- progress |= process_loops(sh, nested_node, &has_nested_loop);
+ progress |= process_loops_in_block(sh, &loop->body, &has_nested_loop);
break;
}
unreachable("unknown cf node type");
}
+ const bool unrolled_child_block = progress;
+
/* Don't attempt to unroll a second inner loop in this pass, wait until the
* next pass as we have altered the cf.
*/
- if (!progress) {
+ if (!progress && loop->control != nir_loop_control_dont_unroll) {
/* Check for the classic
*
unsigned num_lt = list_length(&loop->info->loop_terminator_list);
if (!has_nested_loop && num_lt == 1 && !loop->partially_unrolled &&
loop->info->guessed_trip_count &&
- is_loop_small_enough_to_unroll(sh, loop->info)) {
+ check_unrolling_restrictions(sh, loop)) {
partial_unroll(sh, loop, loop->info->guessed_trip_count);
progress = true;
}
if (has_nested_loop || !loop->info->limiting_terminator)
goto exit;
- if (!is_loop_small_enough_to_unroll(sh, loop->info))
+ if (!check_unrolling_restrictions(sh, loop))
goto exit;
if (loop->info->exact_trip_count_known) {
exit:
*has_nested_loop_out = true;
+ if (progress && !unrolled_child_block)
+ *unrolled_this_block = true;
+
return progress;
}
nir_metadata_require(impl, nir_metadata_loop_analysis, indirect_mask);
nir_metadata_require(impl, nir_metadata_block_index);
- foreach_list_typed_safe(nir_cf_node, node, node, &impl->body) {
- bool has_nested_loop = false;
- progress |= process_loops(impl->function->shader, node,
- &has_nested_loop);
- }
+ bool has_nested_loop = false;
+ progress |= process_loops_in_block(impl->function->shader, &impl->body,
+ &has_nested_loop);
- if (progress)
+ if (progress) {
+ nir_metadata_preserve(impl, nir_metadata_none);
nir_lower_regs_to_ssa_impl(impl);
+ } else {
+ nir_metadata_preserve(impl, nir_metadata_all);
+ }
return progress;
}
projects / mesa.git / blobdiff