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-canonicalize.h" 29 30 namespace v8 { 31 namespace internal { 32 33 void HCanonicalizePhase::Run() { 34 const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); 35 // Before removing no-op instructions, save their semantic value. 36 // We must be careful not to set the flag unnecessarily, because GVN 37 // cannot identify two instructions when their flag value differs. 38 for (int i = 0; i < blocks->length(); ++i) { 39 for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { 40 HInstruction* instr = it.Current(); 41 if (instr->IsArithmeticBinaryOperation()) { 42 if (instr->representation().IsInteger32()) { 43 if (instr->HasAtLeastOneUseWithFlagAndNoneWithout( 44 HInstruction::kTruncatingToInt32)) { 45 instr->SetFlag(HInstruction::kAllUsesTruncatingToInt32); 46 } 47 } else if (instr->representation().IsSmi()) { 48 if (instr->HasAtLeastOneUseWithFlagAndNoneWithout( 49 HInstruction::kTruncatingToSmi)) { 50 instr->SetFlag(HInstruction::kAllUsesTruncatingToSmi); 51 } 52 } 53 } 54 } 55 } 56 // Perform actual Canonicalization pass. 57 for (int i = 0; i < blocks->length(); ++i) { 58 for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { 59 HInstruction* instr = it.Current(); 60 HValue* value = instr->Canonicalize(); 61 if (value != instr) instr->DeleteAndReplaceWith(value); 62 } 63 } 64 } 65 66 } } // namespace v8::internal 67
