Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 1 | // Copyright 2014 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "src/compiler/common-operator-reducer.h" |
| 6 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 7 | #include <algorithm> |
| 8 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 9 | #include "src/compiler/common-operator.h" |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 10 | #include "src/compiler/graph.h" |
| 11 | #include "src/compiler/machine-operator.h" |
| 12 | #include "src/compiler/node.h" |
| 13 | #include "src/compiler/node-matchers.h" |
| 14 | #include "src/compiler/node-properties.h" |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 15 | |
| 16 | namespace v8 { |
| 17 | namespace internal { |
| 18 | namespace compiler { |
| 19 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 20 | namespace { |
| 21 | |
| 22 | enum class Decision { kUnknown, kTrue, kFalse }; |
| 23 | |
| 24 | Decision DecideCondition(Node* const cond) { |
| 25 | switch (cond->opcode()) { |
| 26 | case IrOpcode::kInt32Constant: { |
| 27 | Int32Matcher mcond(cond); |
| 28 | return mcond.Value() ? Decision::kTrue : Decision::kFalse; |
| 29 | } |
| 30 | case IrOpcode::kInt64Constant: { |
| 31 | Int64Matcher mcond(cond); |
| 32 | return mcond.Value() ? Decision::kTrue : Decision::kFalse; |
| 33 | } |
| 34 | case IrOpcode::kHeapConstant: { |
| 35 | HeapObjectMatcher mcond(cond); |
| 36 | return mcond.Value()->BooleanValue() ? Decision::kTrue : Decision::kFalse; |
| 37 | } |
| 38 | default: |
| 39 | return Decision::kUnknown; |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | } // namespace |
| 44 | |
| 45 | |
| 46 | CommonOperatorReducer::CommonOperatorReducer(Editor* editor, Graph* graph, |
| 47 | CommonOperatorBuilder* common, |
| 48 | MachineOperatorBuilder* machine) |
| 49 | : AdvancedReducer(editor), |
| 50 | graph_(graph), |
| 51 | common_(common), |
| 52 | machine_(machine), |
| 53 | dead_(graph->NewNode(common->Dead())) {} |
| 54 | |
| 55 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 56 | Reduction CommonOperatorReducer::Reduce(Node* node) { |
| 57 | switch (node->opcode()) { |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 58 | case IrOpcode::kBranch: |
| 59 | return ReduceBranch(node); |
| 60 | case IrOpcode::kMerge: |
| 61 | return ReduceMerge(node); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 62 | case IrOpcode::kEffectPhi: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 63 | return ReduceEffectPhi(node); |
| 64 | case IrOpcode::kPhi: |
| 65 | return ReducePhi(node); |
| 66 | case IrOpcode::kReturn: |
| 67 | return ReduceReturn(node); |
| 68 | case IrOpcode::kSelect: |
| 69 | return ReduceSelect(node); |
| 70 | case IrOpcode::kGuard: |
| 71 | return ReduceGuard(node); |
| 72 | default: |
| 73 | break; |
| 74 | } |
| 75 | return NoChange(); |
| 76 | } |
| 77 | |
| 78 | |
| 79 | Reduction CommonOperatorReducer::ReduceBranch(Node* node) { |
| 80 | DCHECK_EQ(IrOpcode::kBranch, node->opcode()); |
| 81 | Node* const cond = node->InputAt(0); |
| 82 | // Swap IfTrue/IfFalse on {branch} if {cond} is a BooleanNot and use the input |
| 83 | // to BooleanNot as new condition for {branch}. Note we assume that {cond} was |
| 84 | // already properly optimized before we get here (as guaranteed by the graph |
| 85 | // reduction logic). |
| 86 | if (cond->opcode() == IrOpcode::kBooleanNot) { |
| 87 | for (Node* const use : node->uses()) { |
| 88 | switch (use->opcode()) { |
| 89 | case IrOpcode::kIfTrue: |
| 90 | NodeProperties::ChangeOp(use, common()->IfFalse()); |
| 91 | break; |
| 92 | case IrOpcode::kIfFalse: |
| 93 | NodeProperties::ChangeOp(use, common()->IfTrue()); |
| 94 | break; |
| 95 | default: |
| 96 | UNREACHABLE(); |
| 97 | } |
| 98 | } |
| 99 | // Update the condition of {branch}. No need to mark the uses for revisit, |
| 100 | // since we tell the graph reducer that the {branch} was changed and the |
| 101 | // graph reduction logic will ensure that the uses are revisited properly. |
| 102 | node->ReplaceInput(0, cond->InputAt(0)); |
| 103 | // Negate the hint for {branch}. |
| 104 | NodeProperties::ChangeOp( |
| 105 | node, common()->Branch(NegateBranchHint(BranchHintOf(node->op())))); |
| 106 | return Changed(node); |
| 107 | } |
| 108 | Decision const decision = DecideCondition(cond); |
| 109 | if (decision == Decision::kUnknown) return NoChange(); |
| 110 | Node* const control = node->InputAt(1); |
| 111 | for (Node* const use : node->uses()) { |
| 112 | switch (use->opcode()) { |
| 113 | case IrOpcode::kIfTrue: |
| 114 | Replace(use, (decision == Decision::kTrue) ? control : dead()); |
| 115 | break; |
| 116 | case IrOpcode::kIfFalse: |
| 117 | Replace(use, (decision == Decision::kFalse) ? control : dead()); |
| 118 | break; |
| 119 | default: |
| 120 | UNREACHABLE(); |
| 121 | } |
| 122 | } |
| 123 | return Replace(dead()); |
| 124 | } |
| 125 | |
| 126 | |
| 127 | Reduction CommonOperatorReducer::ReduceMerge(Node* node) { |
| 128 | DCHECK_EQ(IrOpcode::kMerge, node->opcode()); |
| 129 | // |
| 130 | // Check if this is a merge that belongs to an unused diamond, which means |
| 131 | // that: |
| 132 | // |
| 133 | // a) the {Merge} has no {Phi} or {EffectPhi} uses, and |
| 134 | // b) the {Merge} has two inputs, one {IfTrue} and one {IfFalse}, which are |
| 135 | // both owned by the Merge, and |
| 136 | // c) and the {IfTrue} and {IfFalse} nodes point to the same {Branch}. |
| 137 | // |
| 138 | if (node->InputCount() == 2) { |
| 139 | for (Node* const use : node->uses()) { |
| 140 | if (IrOpcode::IsPhiOpcode(use->opcode())) return NoChange(); |
| 141 | } |
| 142 | Node* if_true = node->InputAt(0); |
| 143 | Node* if_false = node->InputAt(1); |
| 144 | if (if_true->opcode() != IrOpcode::kIfTrue) std::swap(if_true, if_false); |
| 145 | if (if_true->opcode() == IrOpcode::kIfTrue && |
| 146 | if_false->opcode() == IrOpcode::kIfFalse && |
| 147 | if_true->InputAt(0) == if_false->InputAt(0) && if_true->OwnedBy(node) && |
| 148 | if_false->OwnedBy(node)) { |
| 149 | Node* const branch = if_true->InputAt(0); |
| 150 | DCHECK_EQ(IrOpcode::kBranch, branch->opcode()); |
| 151 | DCHECK(branch->OwnedBy(if_true, if_false)); |
| 152 | Node* const control = branch->InputAt(1); |
| 153 | // Mark the {branch} as {Dead}. |
| 154 | branch->TrimInputCount(0); |
| 155 | NodeProperties::ChangeOp(branch, common()->Dead()); |
| 156 | return Replace(control); |
| 157 | } |
| 158 | } |
| 159 | return NoChange(); |
| 160 | } |
| 161 | |
| 162 | |
| 163 | Reduction CommonOperatorReducer::ReduceEffectPhi(Node* node) { |
| 164 | DCHECK_EQ(IrOpcode::kEffectPhi, node->opcode()); |
| 165 | int const input_count = node->InputCount() - 1; |
| 166 | DCHECK_LE(1, input_count); |
| 167 | Node* const merge = node->InputAt(input_count); |
| 168 | DCHECK(IrOpcode::IsMergeOpcode(merge->opcode())); |
| 169 | DCHECK_EQ(input_count, merge->InputCount()); |
| 170 | Node* const effect = node->InputAt(0); |
| 171 | DCHECK_NE(node, effect); |
| 172 | for (int i = 1; i < input_count; ++i) { |
| 173 | Node* const input = node->InputAt(i); |
| 174 | if (input == node) { |
| 175 | // Ignore redundant inputs. |
| 176 | DCHECK_EQ(IrOpcode::kLoop, merge->opcode()); |
| 177 | continue; |
| 178 | } |
| 179 | if (input != effect) return NoChange(); |
| 180 | } |
| 181 | // We might now be able to further reduce the {merge} node. |
| 182 | Revisit(merge); |
| 183 | return Replace(effect); |
| 184 | } |
| 185 | |
| 186 | |
| 187 | Reduction CommonOperatorReducer::ReducePhi(Node* node) { |
| 188 | DCHECK_EQ(IrOpcode::kPhi, node->opcode()); |
| 189 | int const input_count = node->InputCount() - 1; |
| 190 | DCHECK_LE(1, input_count); |
| 191 | Node* const merge = node->InputAt(input_count); |
| 192 | DCHECK(IrOpcode::IsMergeOpcode(merge->opcode())); |
| 193 | DCHECK_EQ(input_count, merge->InputCount()); |
| 194 | if (input_count == 2) { |
| 195 | Node* vtrue = node->InputAt(0); |
| 196 | Node* vfalse = node->InputAt(1); |
| 197 | Node* if_true = merge->InputAt(0); |
| 198 | Node* if_false = merge->InputAt(1); |
| 199 | if (if_true->opcode() != IrOpcode::kIfTrue) { |
| 200 | std::swap(if_true, if_false); |
| 201 | std::swap(vtrue, vfalse); |
| 202 | } |
| 203 | if (if_true->opcode() == IrOpcode::kIfTrue && |
| 204 | if_false->opcode() == IrOpcode::kIfFalse && |
| 205 | if_true->InputAt(0) == if_false->InputAt(0)) { |
| 206 | Node* const branch = if_true->InputAt(0); |
| 207 | // Check that the branch is not dead already. |
| 208 | if (branch->opcode() != IrOpcode::kBranch) return NoChange(); |
| 209 | Node* const cond = branch->InputAt(0); |
| 210 | if (cond->opcode() == IrOpcode::kFloat32LessThan) { |
| 211 | Float32BinopMatcher mcond(cond); |
| 212 | if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| 213 | vfalse->opcode() == IrOpcode::kFloat32Sub) { |
| 214 | Float32BinopMatcher mvfalse(vfalse); |
| 215 | if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| 216 | // We might now be able to further reduce the {merge} node. |
| 217 | Revisit(merge); |
| 218 | return Change(node, machine()->Float32Abs(), vtrue); |
| 219 | } |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 220 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 221 | if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| 222 | machine()->Float32Min().IsSupported()) { |
| 223 | // We might now be able to further reduce the {merge} node. |
| 224 | Revisit(merge); |
| 225 | return Change(node, machine()->Float32Min().op(), vtrue, vfalse); |
| 226 | } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| 227 | machine()->Float32Max().IsSupported()) { |
| 228 | // We might now be able to further reduce the {merge} node. |
| 229 | Revisit(merge); |
| 230 | return Change(node, machine()->Float32Max().op(), vtrue, vfalse); |
| 231 | } |
| 232 | } else if (cond->opcode() == IrOpcode::kFloat64LessThan) { |
| 233 | Float64BinopMatcher mcond(cond); |
| 234 | if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| 235 | vfalse->opcode() == IrOpcode::kFloat64Sub) { |
| 236 | Float64BinopMatcher mvfalse(vfalse); |
| 237 | if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| 238 | // We might now be able to further reduce the {merge} node. |
| 239 | Revisit(merge); |
| 240 | return Change(node, machine()->Float64Abs(), vtrue); |
| 241 | } |
| 242 | } |
| 243 | if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| 244 | machine()->Float64Min().IsSupported()) { |
| 245 | // We might now be able to further reduce the {merge} node. |
| 246 | Revisit(merge); |
| 247 | return Change(node, machine()->Float64Min().op(), vtrue, vfalse); |
| 248 | } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| 249 | machine()->Float64Max().IsSupported()) { |
| 250 | // We might now be able to further reduce the {merge} node. |
| 251 | Revisit(merge); |
| 252 | return Change(node, machine()->Float64Max().op(), vtrue, vfalse); |
| 253 | } |
| 254 | } |
| 255 | } |
| 256 | } |
| 257 | Node* const value = node->InputAt(0); |
| 258 | DCHECK_NE(node, value); |
| 259 | for (int i = 1; i < input_count; ++i) { |
| 260 | Node* const input = node->InputAt(i); |
| 261 | if (input == node) { |
| 262 | // Ignore redundant inputs. |
| 263 | DCHECK_EQ(IrOpcode::kLoop, merge->opcode()); |
| 264 | continue; |
| 265 | } |
| 266 | if (input != value) return NoChange(); |
| 267 | } |
| 268 | // We might now be able to further reduce the {merge} node. |
| 269 | Revisit(merge); |
| 270 | return Replace(value); |
| 271 | } |
| 272 | |
| 273 | |
| 274 | Reduction CommonOperatorReducer::ReduceReturn(Node* node) { |
| 275 | DCHECK_EQ(IrOpcode::kReturn, node->opcode()); |
| 276 | Node* const value = node->InputAt(0); |
| 277 | Node* const effect = node->InputAt(1); |
| 278 | Node* const control = node->InputAt(2); |
| 279 | if (value->opcode() == IrOpcode::kPhi && |
| 280 | NodeProperties::GetControlInput(value) == control && |
| 281 | effect->opcode() == IrOpcode::kEffectPhi && |
| 282 | NodeProperties::GetControlInput(effect) == control && |
| 283 | control->opcode() == IrOpcode::kMerge) { |
| 284 | int const control_input_count = control->InputCount(); |
| 285 | DCHECK_NE(0, control_input_count); |
| 286 | DCHECK_EQ(control_input_count, value->InputCount() - 1); |
| 287 | DCHECK_EQ(control_input_count, effect->InputCount() - 1); |
| 288 | DCHECK_EQ(IrOpcode::kEnd, graph()->end()->opcode()); |
| 289 | DCHECK_NE(0, graph()->end()->InputCount()); |
| 290 | for (int i = 0; i < control_input_count; ++i) { |
| 291 | // Create a new {Return} and connect it to {end}. We don't need to mark |
| 292 | // {end} as revisit, because we mark {node} as {Dead} below, which was |
| 293 | // previously connected to {end}, so we know for sure that at some point |
| 294 | // the reducer logic will visit {end} again. |
| 295 | Node* ret = graph()->NewNode(common()->Return(), value->InputAt(i), |
| 296 | effect->InputAt(i), control->InputAt(i)); |
| 297 | NodeProperties::MergeControlToEnd(graph(), common(), ret); |
| 298 | } |
| 299 | // Mark the merge {control} and return {node} as {dead}. |
| 300 | Replace(control, dead()); |
| 301 | return Replace(dead()); |
| 302 | } |
| 303 | return NoChange(); |
| 304 | } |
| 305 | |
| 306 | |
| 307 | Reduction CommonOperatorReducer::ReduceSelect(Node* node) { |
| 308 | DCHECK_EQ(IrOpcode::kSelect, node->opcode()); |
| 309 | Node* const cond = node->InputAt(0); |
| 310 | Node* const vtrue = node->InputAt(1); |
| 311 | Node* const vfalse = node->InputAt(2); |
| 312 | if (vtrue == vfalse) return Replace(vtrue); |
| 313 | switch (DecideCondition(cond)) { |
| 314 | case Decision::kTrue: |
| 315 | return Replace(vtrue); |
| 316 | case Decision::kFalse: |
| 317 | return Replace(vfalse); |
| 318 | case Decision::kUnknown: |
| 319 | break; |
| 320 | } |
| 321 | switch (cond->opcode()) { |
| 322 | case IrOpcode::kFloat32LessThan: { |
| 323 | Float32BinopMatcher mcond(cond); |
| 324 | if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| 325 | vfalse->opcode() == IrOpcode::kFloat32Sub) { |
| 326 | Float32BinopMatcher mvfalse(vfalse); |
| 327 | if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| 328 | return Change(node, machine()->Float32Abs(), vtrue); |
| 329 | } |
| 330 | } |
| 331 | if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| 332 | machine()->Float32Min().IsSupported()) { |
| 333 | return Change(node, machine()->Float32Min().op(), vtrue, vfalse); |
| 334 | } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| 335 | machine()->Float32Max().IsSupported()) { |
| 336 | return Change(node, machine()->Float32Max().op(), vtrue, vfalse); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 337 | } |
| 338 | break; |
| 339 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 340 | case IrOpcode::kFloat64LessThan: { |
| 341 | Float64BinopMatcher mcond(cond); |
| 342 | if (mcond.left().Is(0.0) && mcond.right().Equals(vtrue) && |
| 343 | vfalse->opcode() == IrOpcode::kFloat64Sub) { |
| 344 | Float64BinopMatcher mvfalse(vfalse); |
| 345 | if (mvfalse.left().IsZero() && mvfalse.right().Equals(vtrue)) { |
| 346 | return Change(node, machine()->Float64Abs(), vtrue); |
| 347 | } |
| 348 | } |
| 349 | if (mcond.left().Equals(vtrue) && mcond.right().Equals(vfalse) && |
| 350 | machine()->Float64Min().IsSupported()) { |
| 351 | return Change(node, machine()->Float64Min().op(), vtrue, vfalse); |
| 352 | } else if (mcond.left().Equals(vfalse) && mcond.right().Equals(vtrue) && |
| 353 | machine()->Float64Max().IsSupported()) { |
| 354 | return Change(node, machine()->Float64Max().op(), vtrue, vfalse); |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 355 | } |
| 356 | break; |
| 357 | } |
| 358 | default: |
| 359 | break; |
| 360 | } |
| 361 | return NoChange(); |
| 362 | } |
| 363 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 364 | |
| 365 | Reduction CommonOperatorReducer::ReduceGuard(Node* node) { |
| 366 | DCHECK_EQ(IrOpcode::kGuard, node->opcode()); |
| 367 | Node* const input = NodeProperties::GetValueInput(node, 0); |
| 368 | Type* const input_type = NodeProperties::GetTypeOrAny(input); |
| 369 | Type* const guard_type = OpParameter<Type*>(node); |
| 370 | if (input_type->Is(guard_type)) return Replace(input); |
| 371 | return NoChange(); |
| 372 | } |
| 373 | |
| 374 | |
| 375 | Reduction CommonOperatorReducer::Change(Node* node, Operator const* op, |
| 376 | Node* a) { |
| 377 | node->ReplaceInput(0, a); |
| 378 | node->TrimInputCount(1); |
| 379 | NodeProperties::ChangeOp(node, op); |
| 380 | return Changed(node); |
| 381 | } |
| 382 | |
| 383 | |
| 384 | Reduction CommonOperatorReducer::Change(Node* node, Operator const* op, Node* a, |
| 385 | Node* b) { |
| 386 | node->ReplaceInput(0, a); |
| 387 | node->ReplaceInput(1, b); |
| 388 | node->TrimInputCount(2); |
| 389 | NodeProperties::ChangeOp(node, op); |
| 390 | return Changed(node); |
| 391 | } |
| 392 | |
Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame] | 393 | } // namespace compiler |
| 394 | } // namespace internal |
| 395 | } // namespace v8 |