mstarzinger@chromium.org | e0e1b0d | 2013-07-08 08:38:06 +0000 | [diff] [blame] | 1 | // Copyright 2013 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #include "hydrogen-redundant-phi.h" |
| 29 | |
| 30 | namespace v8 { |
| 31 | namespace internal { |
| 32 | |
| 33 | void HRedundantPhiEliminationPhase::Run() { |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 34 | // Gather all phis from all blocks first. |
mstarzinger@chromium.org | e0e1b0d | 2013-07-08 08:38:06 +0000 | [diff] [blame] | 35 | const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 36 | ZoneList<HPhi*> all_phis(blocks->length(), zone()); |
| 37 | for (int i = 0; i < blocks->length(); ++i) { |
| 38 | HBasicBlock* block = blocks->at(i); |
| 39 | for (int j = 0; j < block->phis()->length(); j++) { |
| 40 | all_phis.Add(block->phis()->at(j), zone()); |
mstarzinger@chromium.org | e0e1b0d | 2013-07-08 08:38:06 +0000 | [diff] [blame] | 41 | } |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 42 | } |
| 43 | |
| 44 | // Iteratively reduce all phis in the list. |
| 45 | ProcessPhis(&all_phis); |
mstarzinger@chromium.org | e0e1b0d | 2013-07-08 08:38:06 +0000 | [diff] [blame] | 46 | |
| 47 | #if DEBUG |
| 48 | // Make sure that we *really* removed all redundant phis. |
| 49 | for (int i = 0; i < blocks->length(); ++i) { |
| 50 | for (int j = 0; j < blocks->at(i)->phis()->length(); j++) { |
| 51 | ASSERT(blocks->at(i)->phis()->at(j)->GetRedundantReplacement() == NULL); |
| 52 | } |
| 53 | } |
| 54 | #endif |
| 55 | } |
| 56 | |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 57 | |
| 58 | void HRedundantPhiEliminationPhase::ProcessBlock(HBasicBlock* block) { |
| 59 | ProcessPhis(block->phis()); |
| 60 | } |
| 61 | |
| 62 | |
| 63 | void HRedundantPhiEliminationPhase::ProcessPhis(const ZoneList<HPhi*>* phis) { |
| 64 | bool updated; |
| 65 | do { |
| 66 | // Iterately replace all redundant phis in the given list. |
| 67 | updated = false; |
| 68 | for (int i = 0; i < phis->length(); i++) { |
| 69 | HPhi* phi = phis->at(i); |
| 70 | if (phi->CheckFlag(HValue::kIsDead)) continue; // Already replaced. |
| 71 | |
| 72 | HValue* replacement = phi->GetRedundantReplacement(); |
| 73 | if (replacement != NULL) { |
| 74 | phi->SetFlag(HValue::kIsDead); |
| 75 | for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) { |
| 76 | HValue* value = it.value(); |
| 77 | value->SetOperandAt(it.index(), replacement); |
| 78 | // Iterate again if used in another non-dead phi. |
| 79 | updated |= value->IsPhi() && !value->CheckFlag(HValue::kIsDead); |
| 80 | } |
| 81 | phi->block()->RemovePhi(phi); |
| 82 | } |
| 83 | } |
| 84 | } while (updated); |
| 85 | } |
| 86 | |
| 87 | |
mstarzinger@chromium.org | e0e1b0d | 2013-07-08 08:38:06 +0000 | [diff] [blame] | 88 | } } // namespace v8::internal |