[turbofan] Merge dependent Word32Equal on ARM64

src/compiler/arm64/instruction-selector-arm64.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1859 matching lines @@
       switch (value->opcode()) {
         case IrOpcode::kInt32Add:
           return VisitWordCompare(this, value, kArm64Cmn32, &cont, true,
                                   kArithmeticImm);
         case IrOpcode::kInt32Sub:
           return VisitWordCompare(this, value, kArm64Cmp32, &cont, false,
                                   kArithmeticImm);
         case IrOpcode::kWord32And:
           return VisitWordCompare(this, value, kArm64Tst32, &cont, true,
                                   kLogical32Imm);
+        case IrOpcode::kWord32Equal: {
+          // Word32Equal(Word32Equal(x, y), 0) => Word32Compare(x, y, ne).
+          Int32BinopMatcher mequal(value);
+          node->ReplaceInput(0, mequal.left().node());
+          node->ReplaceInput(1, mequal.right().node());
+          cont.Negate();
+          return VisitWord32Compare(this, node, &cont);
+        }
         default:
           break;
       }
       return VisitWord32Test(this, value, &cont);
     }
   }
   VisitWord32Compare(this, node, &cont);
 }
 
 
@@ skipping 180 matching lines @@
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8