1/*
2 * Copyright © 2018 Valve Corporation
3 * Copyright © 2018 Google
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 *
24 */
25
26#include "aco_builder.h"
27#include "aco_ir.h"
28
29#include <vector>
30
31/*
32 * Insert p_linear_start instructions right before RA to correctly allocate
33 * temporaries for reductions that have to disrespect EXEC by executing in
34 * WWM.
35 */
36
37namespace aco {
38
39void
40setup_reduce_temp(Program* program)
41{
42   unsigned last_top_level_block_idx = 0;
43   unsigned maxSize = 0;
44
45   std::vector<bool> hasReductions(program->blocks.size());
46   for (Block& block : program->blocks) {
47      for (aco_ptr<Instruction>& instr : block.instructions) {
48         if (instr->format != Format::PSEUDO_REDUCTION)
49            continue;
50
51         maxSize = MAX2(maxSize, instr->operands[0].size());
52         hasReductions[block.index] = true;
53      }
54   }
55
56   if (maxSize == 0)
57      return;
58
59   assert(maxSize == 1 || maxSize == 2);
60   Temp reduceTmp(0, RegClass(RegType::vgpr, maxSize).as_linear());
61   Temp vtmp(0, RegClass(RegType::vgpr, maxSize).as_linear());
62   int inserted_at = -1;
63   int vtmp_inserted_at = -1;
64   bool reduceTmp_in_loop = false;
65   bool vtmp_in_loop = false;
66
67   for (Block& block : program->blocks) {
68
69      /* insert p_end_linear_vgpr after the outermost loop */
70      if (reduceTmp_in_loop && block.loop_nest_depth == 0) {
71         assert(inserted_at == (int)last_top_level_block_idx);
72
73         aco_ptr<Instruction> end{create_instruction<Instruction>(
74            aco_opcode::p_end_linear_vgpr, Format::PSEUDO, vtmp_in_loop ? 2 : 1, 0)};
75         end->operands[0] = Operand(reduceTmp);
76         if (vtmp_in_loop)
77            end->operands[1] = Operand(vtmp);
78         /* insert after the phis of the loop exit block */
79         std::vector<aco_ptr<Instruction>>::iterator it = block.instructions.begin();
80         while ((*it)->opcode == aco_opcode::p_linear_phi || (*it)->opcode == aco_opcode::p_phi)
81            ++it;
82         block.instructions.insert(it, std::move(end));
83         reduceTmp_in_loop = false;
84      }
85
86      if (block.kind & block_kind_top_level)
87         last_top_level_block_idx = block.index;
88
89      if (!hasReductions[block.index])
90         continue;
91
92      std::vector<aco_ptr<Instruction>>::iterator it;
93      for (it = block.instructions.begin(); it != block.instructions.end(); ++it) {
94         Instruction* instr = (*it).get();
95         if (instr->format != Format::PSEUDO_REDUCTION)
96            continue;
97
98         ReduceOp op = instr->reduction().reduce_op;
99         reduceTmp_in_loop |= block.loop_nest_depth > 0;
100
101         if ((int)last_top_level_block_idx != inserted_at) {
102            reduceTmp = program->allocateTmp(reduceTmp.regClass());
103            aco_ptr<Pseudo_instruction> create{create_instruction<Pseudo_instruction>(
104               aco_opcode::p_start_linear_vgpr, Format::PSEUDO, 0, 1)};
105            create->definitions[0] = Definition(reduceTmp);
106            /* find the right place to insert this definition */
107            if (last_top_level_block_idx == block.index) {
108               /* insert right before the current instruction */
109               it = block.instructions.insert(it, std::move(create));
110               it++;
111               /* inserted_at is intentionally not updated here, so later blocks
112                * would insert at the end instead of using this one. */
113            } else {
114               assert(last_top_level_block_idx < block.index);
115               /* insert before the branch at last top level block */
116               std::vector<aco_ptr<Instruction>>& instructions =
117                  program->blocks[last_top_level_block_idx].instructions;
118               instructions.insert(std::next(instructions.begin(), instructions.size() - 1),
119                                   std::move(create));
120               inserted_at = last_top_level_block_idx;
121            }
122         }
123
124         /* same as before, except for the vector temporary instead of the reduce temporary */
125         unsigned cluster_size = instr->reduction().cluster_size;
126         bool need_vtmp = op == imul32 || op == fadd64 || op == fmul64 || op == fmin64 ||
127                          op == fmax64 || op == umin64 || op == umax64 || op == imin64 ||
128                          op == imax64 || op == imul64;
129         bool gfx10_need_vtmp = op == imul8 || op == imax8 || op == imin8 || op == umin8 ||
130                                op == imul16 || op == imax16 || op == imin16 || op == umin16 ||
131                                op == iadd64;
132
133         if (program->gfx_level >= GFX10 && cluster_size == 64)
134            need_vtmp = true;
135         if (program->gfx_level >= GFX10 && gfx10_need_vtmp)
136            need_vtmp = true;
137         if (program->gfx_level <= GFX7)
138            need_vtmp = true;
139
140         need_vtmp |= cluster_size == 32;
141
142         vtmp_in_loop |= need_vtmp && block.loop_nest_depth > 0;
143         if (need_vtmp && (int)last_top_level_block_idx != vtmp_inserted_at) {
144            vtmp = program->allocateTmp(vtmp.regClass());
145            aco_ptr<Pseudo_instruction> create{create_instruction<Pseudo_instruction>(
146               aco_opcode::p_start_linear_vgpr, Format::PSEUDO, 0, 1)};
147            create->definitions[0] = Definition(vtmp);
148            if (last_top_level_block_idx == block.index) {
149               it = block.instructions.insert(it, std::move(create));
150               it++;
151            } else {
152               assert(last_top_level_block_idx < block.index);
153               std::vector<aco_ptr<Instruction>>& instructions =
154                  program->blocks[last_top_level_block_idx].instructions;
155               instructions.insert(std::next(instructions.begin(), instructions.size() - 1),
156                                   std::move(create));
157               vtmp_inserted_at = last_top_level_block_idx;
158            }
159         }
160
161         instr->operands[1] = Operand(reduceTmp);
162         if (need_vtmp)
163            instr->operands[2] = Operand(vtmp);
164      }
165   }
166}
167
168}; // namespace aco
169