Line data    Source code

       1             : // Copyright 2013 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/crankshaft/hydrogen-canonicalize.h"
       6             : 
       7             : #include "src/counters.h"
       8             : #include "src/crankshaft/hydrogen-redundant-phi.h"
       9             : #include "src/objects-inl.h"
      10             : 
      11             : namespace v8 {
      12             : namespace internal {
      13             : 
      14      283728 : void HCanonicalizePhase::Run() {
      15      567457 :   const ZoneList<HBasicBlock*>* blocks(graph()->blocks());
      16             :   // Before removing no-op instructions, save their semantic value.
      17             :   // We must be careful not to set the flag unnecessarily, because GVN
      18             :   // cannot identify two instructions when their flag value differs.
      19     9590384 :   for (int i = 0; i < blocks->length(); ++i) {
      20    47651014 :     for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) {
      21             :       HInstruction* instr = it.Current();
      22    29037479 :       if (instr->IsArithmeticBinaryOperation()) {
      23      399046 :         if (instr->representation().IsInteger32()) {
      24      248661 :           if (instr->HasAtLeastOneUseWithFlagAndNoneWithout(
      25             :                   HInstruction::kTruncatingToInt32)) {
      26             :             instr->SetFlag(HInstruction::kAllUsesTruncatingToInt32);
      27             :           }
      28      150385 :         } else if (instr->representation().IsSmi()) {
      29        1288 :           if (instr->HasAtLeastOneUseWithFlagAndNoneWithout(
      30             :                   HInstruction::kTruncatingToSmi)) {
      31             :             instr->SetFlag(HInstruction::kAllUsesTruncatingToSmi);
      32        1288 :           } else if (instr->HasAtLeastOneUseWithFlagAndNoneWithout(
      33             :                          HInstruction::kTruncatingToInt32)) {
      34             :             // Avoid redundant minus zero check
      35             :             instr->SetFlag(HInstruction::kAllUsesTruncatingToInt32);
      36             :           }
      37             :         }
      38             :       }
      39             :     }
      40             :   }
      41             : 
      42             :   // Perform actual Canonicalization pass.
      43             :   HRedundantPhiEliminationPhase redundant_phi_eliminator(graph());
      44     9590832 :   for (int i = 0; i < blocks->length(); ++i) {
      45             :     // Eliminate redundant phis in the block first; changes to their inputs
      46             :     // might have made them redundant, and eliminating them creates more
      47             :     // opportunities for constant folding and strength reduction.
      48     4511687 :     redundant_phi_eliminator.ProcessBlock(blocks->at(i));
      49             :     // Now canonicalize each instruction.
      50    38062040 :     for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) {
      51             :       HInstruction* instr = it.Current();
      52    29038654 :       HValue* value = instr->Canonicalize();
      53    29038628 :       if (value != instr) instr->DeleteAndReplaceWith(value);
      54             :     }
      55             :   }
      56      283729 : }
      57             : 
      58             : }  // namespace internal
      59             : }  // namespace v8