Mesa (master): aco: refactor try_remove_trivial_phi() in RA
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Thu Apr 9 15:28:03 UTC 2020
Module: Mesa
Branch: master
Commit: 69b6069dd288455cdb2655284c592a85d17df273
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=69b6069dd288455cdb2655284c592a85d17df273
Author: Daniel Schürmann <daniel at schuermann.dev>
Date: Wed Mar 11 08:38:48 2020 +0100
aco: refactor try_remove_trivial_phi() in RA
Minor refactoring to avoid some pointer chasing.
This patch also changes the live_out argument to be
passed by reference to avoid an unnecessary copy.
Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4130>
---
src/amd/compiler/aco_ir.h | 2 +-
src/amd/compiler/aco_register_allocation.cpp | 46 +++++++++++++++-------------
2 files changed, 25 insertions(+), 23 deletions(-)
diff --git a/src/amd/compiler/aco_ir.h b/src/amd/compiler/aco_ir.h
index 8b05482ff92..2a52d6b44de 100644
--- a/src/amd/compiler/aco_ir.h
+++ b/src/amd/compiler/aco_ir.h
@@ -1471,7 +1471,7 @@ void value_numbering(Program* program);
void optimize(Program* program);
void setup_reduce_temp(Program* program);
void lower_to_cssa(Program* program, live& live_vars, const struct radv_nir_compiler_options *options);
-void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_per_block);
+void register_allocation(Program *program, std::vector<std::set<Temp>>& live_out_per_block);
void ssa_elimination(Program* program);
void lower_to_hw_instr(Program* program);
void schedule_program(Program* program, live& live_vars);
diff --git a/src/amd/compiler/aco_register_allocation.cpp b/src/amd/compiler/aco_register_allocation.cpp
index 92006d20561..aab1cd3745f 100644
--- a/src/amd/compiler/aco_register_allocation.cpp
+++ b/src/amd/compiler/aco_register_allocation.cpp
@@ -1097,7 +1097,7 @@ bool operand_can_use_reg(aco_ptr<Instruction>& instr, unsigned idx, PhysReg reg)
} /* end namespace */
-void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_per_block)
+void register_allocation(Program *program, std::vector<std::set<Temp>>& live_out_per_block)
{
ra_ctx ctx(program);
@@ -1118,7 +1118,7 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
std::map<unsigned, unsigned> affinities;
std::function<Temp(Temp,unsigned)> read_variable;
std::function<Temp(Temp,Block*)> handle_live_in;
- std::function<Temp(std::map<unsigned, phi_info>::iterator)> try_remove_trivial_phi;
+ std::function<void(Temp)> try_remove_trivial_phi;
read_variable = [&](Temp val, unsigned block_idx) -> Temp {
std::unordered_map<unsigned, Temp>::iterator it = renames[block_idx].find(val.id());
@@ -1198,27 +1198,33 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
return new_val;
};
- try_remove_trivial_phi = [&] (std::map<unsigned, phi_info>::iterator info) -> Temp {
+ try_remove_trivial_phi = [&] (Temp temp) -> void {
+ std::map<unsigned, phi_info>::iterator info = phi_map.find(temp.id());
+
+ if (info == phi_map.end() || !sealed[info->second.block_idx])
+ return;
+
assert(info->second.block_idx != 0);
Instruction* phi = info->second.phi;
Temp same = Temp();
-
Definition def = phi->definitions[0];
+
/* a phi node is trivial if all operands are the same as the definition of the phi */
for (const Operand& op : phi->operands) {
const Temp t = op.getTemp();
- if (t == same || t == def.getTemp())
+ if (t == same || t == def.getTemp()) {
+ assert(t == same || op.physReg() == def.physReg());
continue;
- if (!(same == Temp()) || !(op.physReg() == def.physReg())) {
- /* phi is not trivial */
- return def.getTemp();
}
+ if (same != Temp())
+ return;
+
same = t;
}
- assert(!(same == Temp() || same == def.getTemp()));
+ assert(same != Temp() || same == def.getTemp());
/* reroute all uses to same and remove phi */
- std::vector<std::map<unsigned, phi_info>::iterator> phi_users;
+ std::vector<Temp> phi_users;
std::map<unsigned, phi_info>::iterator same_phi_info = phi_map.find(same.id());
for (Instruction* instr : info->second.uses) {
assert(phi != instr);
@@ -1228,9 +1234,8 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
if (instr->definitions.empty())
continue;
- std::map<unsigned, phi_info>::iterator it = phi_map.find(instr->definitions[0].tempId());
- if (it != phi_map.end() && it != info)
- phi_users.emplace_back(it);
+ if (instr->definitions[0].getTemp() != temp)
+ phi_users.emplace_back(instr->definitions[0].getTemp());
}
for (Operand& op : instr->operands) {
if (op.isTemp() && op.tempId() == def.tempId()) {
@@ -1249,16 +1254,12 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
renames[i][orig_var] = same;
}
- unsigned block_idx = info->second.block_idx;
phi->definitions.clear(); /* this indicates that the phi can be removed */
phi_map.erase(info);
- for (auto it : phi_users) {
- if (sealed[it->second.block_idx])
- try_remove_trivial_phi(it);
- }
+ for (Temp t : phi_users)
+ try_remove_trivial_phi(t);
- /* due to the removal of other phis, the name might have changed once again! */
- return renames[block_idx][orig_var];
+ return;
};
std::map<unsigned, Instruction*> vectors;
@@ -2019,6 +2020,8 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
}
}
if (all_filled) {
+ sealed[succ_idx] = true;
+
/* finish incomplete phis and check if they became trivial */
for (Instruction* phi : incomplete_phis[succ_idx]) {
std::vector<unsigned> preds = phi->definitions[0].getTemp().is_linear() ? succ.linear_preds : succ.logical_preds;
@@ -2026,7 +2029,7 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
phi->operands[i].setTemp(read_variable(phi->operands[i].getTemp(), preds[i]));
phi->operands[i].setFixed(ctx.assignments[phi->operands[i].tempId()].reg);
}
- try_remove_trivial_phi(phi_map.find(phi->definitions[0].tempId()));
+ try_remove_trivial_phi(phi->definitions[0].getTemp());
}
/* complete the original phi nodes, but no need to check triviality */
for (aco_ptr<Instruction>& instr : succ.instructions) {
@@ -2045,7 +2048,6 @@ void register_allocation(Program *program, std::vector<std::set<Temp>> live_out_
phi->second.uses.emplace(instr.get());
}
}
- sealed[succ_idx] = true;
}
}
} /* end for BB */
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