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aco: end reduce tmp after control flow, when used within control flow

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In the case of:

v0 = start_linear_vgpr
if (...) {

} else {
   use_linear_vgpr(v0)
}
v0 = phi

We need a p_end_linear_vgpr to ensure that the phi does not use the same
VGPR as the linear VGPR.

fossil-db (gfx1100):
Totals from 3763 (2.80% of 134574) affected shaders:
MaxWaves: 90296 -> 90164 (-0.15%)
Instrs: 6857726 -> 6856608 (-0.02%); split: -0.03%, +0.01%
CodeSize: 35382188 -> 35377688 (-0.01%); split: -0.02%, +0.01%
VGPRs: 234864 -> 235692 (+0.35%); split: -0.01%, +0.36%
Latency: 47471923 -> 47474965 (+0.01%); split: -0.03%, +0.04%
InvThroughput: 5640320 -> 5639736 (-0.01%); split: -0.04%, +0.03%
VClause: 93098 -> 93107 (+0.01%); split: -0.01%, +0.02%
SClause: 214137 -> 214130 (-0.00%); split: -0.00%, +0.00%
Copies: 369895 -> 369305 (-0.16%); split: -0.31%, +0.15%
Branches: 164996 -> 164504 (-0.30%); split: -0.30%, +0.00%
PreVGPRs: 210655 -> 211438 (+0.37%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20621>
(cherry picked from commit 44fdd2ebcb)
This commit is contained in:
Rhys Perry 2023-01-10 15:29:15 +00:00 • committed by Dylan Baker
parent 1cafb71a19
commit 7c53e5748b
2 changed files with 25 additions and 22 deletions
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2
.pick_status.json
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@ -265,7 +265,7 @@
"description": "aco: end reduce tmp after control flow, when used within control flow",
"nominated": true,
"nomination_type": 0,
"resolution": 0,
"resolution": 1,
"main_sha": null,
"because_sha": null
},

45
src/amd/compiler/aco_reduce_assign.cpp
View file

@ -64,31 +64,36 @@ setup_reduce_temp(Program* program)
Temp vtmp(0, RegClass(RegType::vgpr, maxSize).as_linear());
int inserted_at = -1;
int vtmp_inserted_at = -1;
bool reduceTmp_in_loop = false;
bool vtmp_in_loop = false;
for (Block& block : program->blocks) {
/* insert p_end_linear_vgpr after the outermost loop */
if (reduceTmp_in_loop && block.loop_nest_depth == 0) {
assert(inserted_at == (int)last_top_level_block_idx);
aco_ptr<Instruction> end{create_instruction<Instruction>(
aco_opcode::p_end_linear_vgpr, Format::PSEUDO, vtmp_in_loop ? 2 : 1, 0)};
end->operands[0] = Operand(reduceTmp);
if (vtmp_in_loop)
end->operands[1] = Operand(vtmp);
/* insert after the phis of the loop exit block */
std::vector<aco_ptr<Instruction>>::iterator it = block.instructions.begin();
while ((*it)->opcode == aco_opcode::p_linear_phi || (*it)->opcode == aco_opcode::p_phi)
++it;
block.instructions.insert(it, std::move(end));
reduceTmp_in_loop = false;
}
if (block.kind & block_kind_top_level)
if (block.kind & block_kind_top_level) {
last_top_level_block_idx = block.index;
/* TODO: this could be improved in this case:
* start_linear_vgpr
* if (...) {
* use_linear_vgpr
* }
* end_linear_vgpr
* Here, the linear vgpr is used before any phi copies, so this isn't necessary.
*/
if (inserted_at >= 0) {
aco_ptr<Instruction> end{create_instruction<Instruction>(
aco_opcode::p_end_linear_vgpr, Format::PSEUDO, vtmp_inserted_at >= 0 ? 2 : 1, 0)};
end->operands[0] = Operand(reduceTmp);
if (vtmp_inserted_at >= 0)
end->operands[1] = Operand(vtmp);
/* insert after the phis of the block */
std::vector<aco_ptr<Instruction>>::iterator it = block.instructions.begin();
while ((*it)->opcode == aco_opcode::p_linear_phi || (*it)->opcode == aco_opcode::p_phi)
++it;
block.instructions.insert(it, std::move(end));
inserted_at = vtmp_inserted_at = -1;
}
}
if (!hasReductions[block.index])
continue;
@ -100,8 +105,6 @@ setup_reduce_temp(Program* program)
instr->opcode != aco_opcode::p_bpermute_gfx11w64)
continue;
reduceTmp_in_loop |= block.loop_nest_depth > 0;
if ((int)last_top_level_block_idx != inserted_at) {
reduceTmp = program->allocateTmp(reduceTmp.regClass());
aco_ptr<Pseudo_instruction> create{create_instruction<Pseudo_instruction>(