/** @file nir_opt_conditional_discard.c
*
- * Handles optimization of lowering if (cond) discard to discard_if(cond).
+ * Handles optimization of lowering of
+ * - if (cond) discard to discard_if(cond) and
+ * - if (cond) demote to demote_if(cond)
*/
static bool
-nir_opt_conditional_discard_block(nir_block *block, void *mem_ctx)
+nir_opt_conditional_discard_block(nir_builder *b, nir_block *block)
{
- nir_builder bld;
-
if (nir_cf_node_is_first(&block->cf_node))
return false;
}
/* Get the first instruction in the then block and confirm it is
- * a discard or a discard_if
+ * a discard or a demote instruction.
*/
nir_instr *instr = nir_block_first_instr(then_block);
if (instr->type != nir_instr_type_intrinsic)
return false;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
- if (intrin->intrinsic != nir_intrinsic_discard &&
- intrin->intrinsic != nir_intrinsic_discard_if)
+ nir_intrinsic_op op = intrin->intrinsic;
+ assert(if_stmt->condition.is_ssa);
+ nir_ssa_def *cond = if_stmt->condition.ssa;
+ b->cursor = nir_before_cf_node(prev_node);
+
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_discard:
+ op = nir_intrinsic_discard_if;
+ break;
+ case nir_intrinsic_demote:
+ op = nir_intrinsic_demote_if;
+ break;
+ case nir_intrinsic_discard_if:
+ case nir_intrinsic_demote_if:
+ assert(intrin->src[0].is_ssa);
+ cond = nir_iand(b, cond, intrin->src[0].ssa);
+ break;
+ default:
return false;
-
- nir_src cond;
-
- nir_builder_init(&bld, mem_ctx);
- bld.cursor = nir_before_cf_node(prev_node);
- if (intrin->intrinsic == nir_intrinsic_discard)
- cond = if_stmt->condition;
- else
- cond = nir_src_for_ssa(nir_iand(&bld,
- nir_ssa_for_src(&bld, if_stmt->condition, 1),
- nir_ssa_for_src(&bld, intrin->src[0], 1)));
+ }
nir_intrinsic_instr *discard_if =
- nir_intrinsic_instr_create(mem_ctx, nir_intrinsic_discard_if);
- nir_src_copy(&discard_if->src[0], &cond, discard_if);
+ nir_intrinsic_instr_create(b->shader, op);
+ discard_if->src[0] = nir_src_for_ssa(cond);
nir_instr_insert_before_cf(prev_node, &discard_if->instr);
nir_instr_remove(&intrin->instr);
{
bool progress = false;
+ nir_builder builder;
+
nir_foreach_function(function, shader) {
if (function->impl) {
- void *mem_ctx = ralloc_parent(function->impl);
+ nir_builder_init(&builder, function->impl);
+
+ bool impl_progress = false;
nir_foreach_block_safe(block, function->impl) {
- progress |= nir_opt_conditional_discard_block(block, mem_ctx);
+ if (nir_opt_conditional_discard_block(&builder, block))
+ impl_progress = true;
+ }
+
+ if (impl_progress) {
+ nir_metadata_preserve(function->impl, nir_metadata_none);
+ progress = true;
+ } else {
+ nir_metadata_preserve(function->impl, nir_metadata_all);
}
}
}