danno@chromium.org | 169691d | 2013-07-15 08:01:13 +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 |
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| 27 | |
| 28 | #include "hydrogen-canonicalize.h" |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 29 | #include "hydrogen-redundant-phi.h" |
danno@chromium.org | 169691d | 2013-07-15 08:01:13 +0000 | [diff] [blame] | 30 | |
| 31 | namespace v8 { |
| 32 | namespace internal { |
| 33 | |
| 34 | void HCanonicalizePhase::Run() { |
| 35 | const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); |
| 36 | // Before removing no-op instructions, save their semantic value. |
| 37 | // We must be careful not to set the flag unnecessarily, because GVN |
| 38 | // cannot identify two instructions when their flag value differs. |
| 39 | for (int i = 0; i < blocks->length(); ++i) { |
| 40 | for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { |
| 41 | HInstruction* instr = it.Current(); |
jkummerow@chromium.org | fb732b1 | 2013-07-26 10:27:09 +0000 | [diff] [blame] | 42 | if (instr->IsArithmeticBinaryOperation()) { |
| 43 | if (instr->representation().IsInteger32()) { |
| 44 | if (instr->HasAtLeastOneUseWithFlagAndNoneWithout( |
| 45 | HInstruction::kTruncatingToInt32)) { |
| 46 | instr->SetFlag(HInstruction::kAllUsesTruncatingToInt32); |
| 47 | } |
| 48 | } else if (instr->representation().IsSmi()) { |
| 49 | if (instr->HasAtLeastOneUseWithFlagAndNoneWithout( |
| 50 | HInstruction::kTruncatingToSmi)) { |
| 51 | instr->SetFlag(HInstruction::kAllUsesTruncatingToSmi); |
verwaest@chromium.org | 662436e | 2013-08-28 08:41:27 +0000 | [diff] [blame] | 52 | } else if (instr->HasAtLeastOneUseWithFlagAndNoneWithout( |
| 53 | HInstruction::kTruncatingToInt32)) { |
| 54 | // Avoid redundant minus zero check |
| 55 | instr->SetFlag(HInstruction::kAllUsesTruncatingToInt32); |
jkummerow@chromium.org | fb732b1 | 2013-07-26 10:27:09 +0000 | [diff] [blame] | 56 | } |
| 57 | } |
danno@chromium.org | 169691d | 2013-07-15 08:01:13 +0000 | [diff] [blame] | 58 | } |
| 59 | } |
| 60 | } |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 61 | |
danno@chromium.org | 169691d | 2013-07-15 08:01:13 +0000 | [diff] [blame] | 62 | // Perform actual Canonicalization pass. |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 63 | HRedundantPhiEliminationPhase redundant_phi_eliminator(graph()); |
danno@chromium.org | 169691d | 2013-07-15 08:01:13 +0000 | [diff] [blame] | 64 | for (int i = 0; i < blocks->length(); ++i) { |
mvstanton@chromium.org | 63ea3d2 | 2013-10-10 09:24:12 +0000 | [diff] [blame] | 65 | // Eliminate redundant phis in the block first; changes to their inputs |
| 66 | // might have made them redundant, and eliminating them creates more |
| 67 | // opportunities for constant folding and strength reduction. |
| 68 | redundant_phi_eliminator.ProcessBlock(blocks->at(i)); |
| 69 | // Now canonicalize each instruction. |
danno@chromium.org | 169691d | 2013-07-15 08:01:13 +0000 | [diff] [blame] | 70 | for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { |
| 71 | HInstruction* instr = it.Current(); |
| 72 | HValue* value = instr->Canonicalize(); |
| 73 | if (value != instr) instr->DeleteAndReplaceWith(value); |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | } } // namespace v8::internal |