aco/scheduler: refactor downwards dependency check

We can also ignore killed operands when checking for RAR dependencies
as these cannot appear later anymore.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38135>
This commit is contained in:
Daniel Schürmann 2025-10-28 08:14:07 +01:00 committed by Marge Bot
parent ce3cc03153
commit 65ba8a0e8b

View file

@ -30,7 +30,7 @@ namespace aco {
namespace {
enum MoveResult {
move_success,
move_success = 0,
move_fail_ssa,
move_fail_rar,
move_fail_pressure,
@ -94,6 +94,7 @@ struct MoveState {
/* for moving instructions before the current instruction to after it */
DownwardsCursor downwards_init(int current_idx, bool improved_rar);
MoveResult downwards_check_deps(Instruction* instr);
MoveResult downwards_move(DownwardsCursor&);
MoveResult downwards_move_clause(DownwardsCursor&);
void downwards_skip(DownwardsCursor&);
@ -183,23 +184,27 @@ MoveState::downwards_init(int current_idx, bool improved_rar_)
return cursor;
}
bool
check_dependencies(Instruction* instr, std::vector<bool>& def_dep,
aco::unordered_map<unsigned, unsigned>& rar_deps, bool improved_rar)
MoveResult
MoveState::downwards_check_deps(Instruction* instr)
{
for (const Definition& def : instr->definitions) {
if (def.isTemp() && def_dep[def.tempId()])
return true;
if (def.isTemp() && depends_on[def.tempId()])
return move_fail_ssa;
}
for (const Operand& op : instr->operands) {
if (op.isTemp()) {
if ((improved_rar && rar_deps.count(op.tempId())) ||
(!improved_rar && def_dep[op.tempId()]))
// FIXME: account for difference in register pressure
return true;
}
if (!op.isTemp() || op.isKill())
continue;
if (!improved_rar && depends_on[op.tempId()])
return move_fail_rar;
if (improved_rar && rar_dependencies.count(op.tempId()))
// FIXME: account for difference in register pressure
return move_fail_rar;
}
return false;
return move_success;
}
/* The instruction at source_idx is moved below the instruction at insert_idx. */
@ -209,8 +214,9 @@ MoveState::downwards_move(DownwardsCursor& cursor)
aco_ptr<Instruction>& candidate = block->instructions[cursor.source_idx];
/* check if one of candidate's operands is killed by depending instruction */
if (check_dependencies(candidate.get(), depends_on, rar_dependencies, improved_rar))
return move_fail_ssa;
MoveResult res = downwards_check_deps(candidate.get());
if (res != move_success)
return res;
/* Check the new demand of the instructions being moved over:
* total_demand doesn't include the current clause which consists of exactly 1 instruction.
@ -281,8 +287,9 @@ MoveState::downwards_move_clause(DownwardsCursor& cursor)
while (should_form_clause(block->instructions[clause_begin_idx].get(), instr)) {
Instruction* candidate = block->instructions[clause_begin_idx--].get();
if (check_dependencies(candidate, depends_on, rar_dependencies, true))
return move_fail_ssa;
MoveResult res = downwards_check_deps(candidate);
if (res != move_success)
return res;
max_clause_demand.update(candidate->register_demand);
}