| Index: src/compiler/x64/code-generator-x64.cc
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| diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
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| index 1a96a3a4c7950bdc9abbace94c806af4e1fdd954..7ecf442fc612a517498a1250ddfffc623b04eb28 100644
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| --- a/src/compiler/x64/code-generator-x64.cc
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| +++ b/src/compiler/x64/code-generator-x64.cc
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| @@ -2243,6 +2243,30 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
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|        __ xchgl(i.InputRegister(0), i.MemoryOperand(1));
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|        break;
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|      }
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| +    case kAtomicCompareExchangeInt8: {
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| +      __ cmpxchgb(i.MemoryOperand(2), i.InputRegister(1));
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| +      __ movsxbl(rax, rax);
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| +      break;
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| +    }
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| +    case kAtomicCompareExchangeUint8: {
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| +      __ cmpxchgb(i.MemoryOperand(2), i.InputRegister(1));
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| +      __ movzxbl(rax, rax);
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| +      break;
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| +    }
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| +    case kAtomicCompareExchangeInt16: {
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| +      __ cmpxchgw(i.MemoryOperand(2), i.InputRegister(1));
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| +      __ movsxwl(rax, rax);
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| +      break;
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| +    }
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| +    case kAtomicCompareExchangeUint16: {
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| +      __ cmpxchgw(i.MemoryOperand(2), i.InputRegister(1));
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| +      __ movzxwl(rax, rax);
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| +      break;
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| +    }
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| +    case kAtomicCompareExchangeWord32: {
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| +      __ cmpxchgl(i.MemoryOperand(2), i.InputRegister(1));
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| +      break;
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| +    }
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|      case kAtomicLoadInt8:
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|      case kAtomicLoadUint8:
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|      case kAtomicLoadInt16:
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| 
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