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aco/ra: don't rewrite affinities for phi operands after register assignment

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The effect of doing so is random and not meaningful.

Totals from 52 (0.03% of 150170) affected shaders: (GFX10.3)
CodeSize: 538768 -> 538784 (+0.00%); split: -0.04%, +0.04%
Instrs: 100661 -> 100707 (+0.05%); split: -0.01%, +0.06%
Latency: 1205950 -> 1205768 (-0.02%); split: -0.07%, +0.05%
InvThroughput: 200106 -> 200040 (-0.03%); split: -0.31%, +0.28%
Copies: 5717 -> 5754 (+0.65%); split: -0.17%, +0.82%
Branches: 3153 -> 3162 (+0.29%)

Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12836>
This commit is contained in:
Daniel Schürmann 2021-09-08 11:56:52 +02:00 • committed by Marge Bot
parent b7af10449b
commit 7b04c13a34
1 changed files with 53 additions and 57 deletions
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110
src/amd/compiler/aco_register_allocation.cpp
View file

@ -1987,69 +1987,65 @@ get_regs_for_phis(ra_ctx& ctx, Block& block, RegisterFile& register_file,
if (definition.isKill())
continue;
if (!definition.isFixed()) {
std::vector<std::pair<Operand, Definition>> parallelcopy;
definition.setFixed(get_reg(ctx, register_file, definition.getTemp(), parallelcopy, phi));
update_renames(ctx, register_file, parallelcopy, phi, rename_not_killed_ops);
if (definition.isFixed()) {
instructions.emplace_back(std::move(phi));
continue;
}
/* process parallelcopy */
for (std::pair<Operand, Definition> pc : parallelcopy) {
/* see if it's a copy from a different phi */
// TODO: prefer moving some previous phis over live-ins
// TODO: somehow prevent phis fixed before the RA from being updated (shouldn't be a
// problem in practice since they can only be fixed to exec)
Instruction* prev_phi = NULL;
std::vector<aco_ptr<Instruction>>::iterator phi_it;
for (phi_it = instructions.begin(); phi_it != instructions.end(); ++phi_it) {
if ((*phi_it)->definitions[0].tempId() == pc.first.tempId())
prev_phi = phi_it->get();
}
if (prev_phi) {
/* if so, just update that phi's register */
prev_phi->definitions[0].setFixed(pc.second.physReg());
ctx.assignments[prev_phi->definitions[0].tempId()].set(pc.second);
continue;
}
std::vector<std::pair<Operand, Definition>> parallelcopy;
definition.setFixed(get_reg(ctx, register_file, definition.getTemp(), parallelcopy, phi));
update_renames(ctx, register_file, parallelcopy, phi, rename_not_killed_ops);
/* rename */
std::unordered_map<unsigned, Temp>::iterator orig_it =
ctx.orig_names.find(pc.first.tempId());
Temp orig = pc.first.getTemp();
if (orig_it != ctx.orig_names.end())
orig = orig_it->second;
else
ctx.orig_names[pc.second.tempId()] = orig;
ctx.renames[block.index][orig.id()] = pc.second.getTemp();
/* otherwise, this is a live-in and we need to create a new phi
* to move it in this block's predecessors */
aco_opcode opcode =
pc.first.getTemp().is_linear() ? aco_opcode::p_linear_phi : aco_opcode::p_phi;
std::vector<unsigned>& preds =
pc.first.getTemp().is_linear() ? block.linear_preds : block.logical_preds;
aco_ptr<Instruction> new_phi{
create_instruction<Pseudo_instruction>(opcode, Format::PSEUDO, preds.size(), 1)};
new_phi->definitions[0] = pc.second;
for (unsigned i = 0; i < preds.size(); i++)
new_phi->operands[i] = Operand(pc.first);
instructions.emplace_back(std::move(new_phi));
/* Remove from live_out_per_block (now used for live-in), because handle_loop_phis()
* would re-create this phi later if this is a loop header.
*/
live_in.erase(orig.id());
/* process parallelcopy */
for (std::pair<Operand, Definition> pc : parallelcopy) {
/* see if it's a copy from a different phi */
// TODO: prefer moving some previous phis over live-ins
// TODO: somehow prevent phis fixed before the RA from being updated (shouldn't be a
// problem in practice since they can only be fixed to exec)
Instruction* prev_phi = NULL;
std::vector<aco_ptr<Instruction>>::iterator phi_it;
for (phi_it = instructions.begin(); phi_it != instructions.end(); ++phi_it) {
if ((*phi_it)->definitions[0].tempId() == pc.first.tempId())
prev_phi = phi_it->get();
}
if (prev_phi) {
/* if so, just update that phi's register */
prev_phi->definitions[0].setFixed(pc.second.physReg());
ctx.assignments[prev_phi->definitions[0].tempId()].set(pc.second);
continue;
}
register_file.fill(definition);
ctx.assignments[definition.tempId()].set(definition);
}
/* update phi affinities */
for (const Operand& op : phi->operands) {
if (op.isTemp() && op.regClass() == phi->definitions[0].regClass())
ctx.assignments[op.tempId()].affinity = definition.tempId();
/* rename */
std::unordered_map<unsigned, Temp>::iterator orig_it =
ctx.orig_names.find(pc.first.tempId());
Temp orig = pc.first.getTemp();
if (orig_it != ctx.orig_names.end())
orig = orig_it->second;
else
ctx.orig_names[pc.second.tempId()] = orig;
ctx.renames[block.index][orig.id()] = pc.second.getTemp();
/* otherwise, this is a live-in and we need to create a new phi
* to move it in this block's predecessors */
aco_opcode opcode =
pc.first.getTemp().is_linear() ? aco_opcode::p_linear_phi : aco_opcode::p_phi;
std::vector<unsigned>& preds =
pc.first.getTemp().is_linear() ? block.linear_preds : block.logical_preds;
aco_ptr<Instruction> new_phi{
create_instruction<Pseudo_instruction>(opcode, Format::PSEUDO, preds.size(), 1)};
new_phi->definitions[0] = pc.second;
for (unsigned i = 0; i < preds.size(); i++)
new_phi->operands[i] = Operand(pc.first);
instructions.emplace_back(std::move(new_phi));
/* Remove from live_out_per_block (now used for live-in), because handle_loop_phis()
* would re-create this phi later if this is a loop header.
*/
live_in.erase(orig.id());
}
register_file.fill(definition);
ctx.assignments[definition.tempId()].set(definition);
instructions.emplace_back(std::move(phi));
}
}