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aco/scheduler: Clean up register demand tracking

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Refactoring total_demand and total_demand_clause to cover non-overlapping
instruction intervals makes the code easier to follow and allows the register
demand to be updated more efficiently in some cases.

Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10885>
This commit is contained in:
Tony Wasserka
2021-05-10 11:54:21 +02:00
parent 2ebf4e984b
commit 81761a311e
1 changed files with 30 additions and 25 deletions
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src/amd/compiler/aco_scheduler.cpp
+30 -25
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@@ -64,7 +64,7 @@ struct MoveState {
int source_idx;
int insert_idx, insert_idx_clause;
RegisterDemand total_demand, total_demand_clause;
RegisterDemand clause_demand, total_demand;
/* for moving instructions before the current instruction to after it */
void downwards_init(int current_idx, bool improved_rar, bool may_form_clauses);
@@ -125,12 +125,13 @@ void MoveState::downwards_advance_helper()
for (int i = source_idx + 1; i < insert_idx_clause; ++i) {
reference_demand.update(register_demand[i]);
}
assert(total_demand_clause == reference_demand);
assert(total_demand == reference_demand);
reference_demand = {};
for (int i = insert_idx_clause; i < insert_idx; ++i) {
reference_demand.update(register_demand[i]);
}
assert(total_demand == reference_demand);
assert(clause_demand == reference_demand);
#endif
}
@@ -142,8 +143,8 @@ void MoveState::downwards_init(int current_idx, bool improved_rar_, bool may_for
insert_idx = current_idx + 1;
insert_idx_clause = current_idx;
total_demand = register_demand[current_idx];
total_demand_clause = {};
clause_demand = register_demand[current_idx];
total_demand = {};
std::fill(depends_on.begin(), depends_on.end(), false);
if (improved_rar) {
@@ -164,7 +165,10 @@ void MoveState::downwards_init(int current_idx, bool improved_rar_, bool may_for
downwards_advance_helper();
}
MoveResult MoveState::downwards_move(bool clause)
/* If add_to_clause is true, the current clause is extended by moving the
* instruction at source_idx in front of the clause. Otherwise, the instruction
* is moved past the end of the clause without extending it */
MoveResult MoveState::downwards_move(bool add_to_clause)
{
aco_ptr<Instruction>& instr = block->instructions[source_idx];
@@ -173,7 +177,7 @@ MoveResult MoveState::downwards_move(bool clause)
return move_fail_ssa;
/* check if one of candidate's operands is killed by depending instruction */
std::vector<bool>& RAR_deps = improved_rar ? (clause ? RAR_dependencies_clause : RAR_dependencies) : depends_on;
std::vector<bool>& RAR_deps = improved_rar ? (add_to_clause ? RAR_dependencies_clause : RAR_dependencies) : depends_on;
for (const Operand& op : instr->operands) {
if (op.isTemp() && RAR_deps[op.tempId()]) {
// FIXME: account for difference in register pressure
@@ -181,7 +185,7 @@ MoveResult MoveState::downwards_move(bool clause)
}
}
if (clause) {
if (add_to_clause) {
for (const Operand& op : instr->operands) {
if (op.isTemp()) {
depends_on[op.tempId()] = true;
@@ -191,13 +195,19 @@ MoveResult MoveState::downwards_move(bool clause)
}
}
const int dest_insert_idx = clause ? insert_idx_clause : insert_idx;
const RegisterDemand register_pressure = clause ? total_demand_clause : total_demand;
const int dest_insert_idx = add_to_clause ? insert_idx_clause : insert_idx;
RegisterDemand register_pressure = total_demand;
if (!add_to_clause) {
register_pressure.update(clause_demand);
}
/* Check the new demand of the instructions being moved over */
const RegisterDemand candidate_diff = get_live_changes(instr);
const RegisterDemand temp = get_temp_registers(instr);
if (RegisterDemand(register_pressure - candidate_diff).exceeds(max_registers))
return move_fail_pressure;
/* New demand for the moved instruction */
const RegisterDemand temp = get_temp_registers(instr);
const RegisterDemand temp2 = get_temp_registers(block->instructions[dest_insert_idx - 1]);
const RegisterDemand new_demand = register_demand[dest_insert_idx - 1] - temp2 + temp;
if (new_demand.exceeds(max_registers))
@@ -212,21 +222,17 @@ MoveResult MoveState::downwards_move(bool clause)
register_demand[i] -= candidate_diff;
register_demand[dest_insert_idx - 1] = new_demand;
insert_idx_clause--;
total_demand_clause -= candidate_diff;
if (source_idx == insert_idx_clause) {
total_demand_clause = RegisterDemand{};
}
if (!clause) {
if (source_idx != insert_idx_clause) {
/* Update demand if we moved over any instructions before the clause */
total_demand -= candidate_diff;
insert_idx--;
} else {
/* The local demand of clause instructions did not change. But if
* previously total_demand_clause was greater than or equal to
* total_demand, the global maximum may have changed still */
total_demand = total_demand_clause;
for (int i = insert_idx_clause; i < insert_idx; ++i) {
total_demand.update(register_demand[i]);
}
assert(total_demand == RegisterDemand{});
}
if (add_to_clause) {
clause_demand.update(new_demand);
} else {
clause_demand -= candidate_diff;
insert_idx--;
}
downwards_advance_helper();
@@ -246,7 +252,6 @@ void MoveState::downwards_skip()
}
}
}
total_demand_clause.update(register_demand[source_idx]);
total_demand.update(register_demand[source_idx]);
downwards_advance_helper();