| Index: src/compiler/arm64/code-generator-arm64.cc | 
| diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc | 
| index 36bd944648d4ffebf00ef455aeaabb35a064d833..a72070a06d1b6b5045461f2f6a353b9622bcd3b3 100644 | 
| --- a/src/compiler/arm64/code-generator-arm64.cc | 
| +++ b/src/compiler/arm64/code-generator-arm64.cc | 
| @@ -556,6 +556,19 @@ Condition FlagsConditionToCondition(FlagsCondition condition) { | 
| __ bind(&exit);                                                       \ | 
| } while (0) | 
|  | 
| +#define ASSEMBLE_ATOMIC_BINOP(load_instr, store_instr, bin_instr)      \ | 
| +  do {                                                                 \ | 
| +    Label binop;                                                       \ | 
| +    __ Add(i.TempRegister(0), i.InputRegister(0), i.InputRegister(1)); \ | 
| +    __ bind(&binop);                                                   \ | 
| +    __ load_instr(i.OutputRegister32(), i.TempRegister(0));            \ | 
| +    __ bin_instr(i.TempRegister32(1), i.OutputRegister32(),            \ | 
| +                 Operand(i.InputRegister32(2)));                       \ | 
| +    __ store_instr(i.TempRegister32(1), i.TempRegister32(1),           \ | 
| +                   i.TempRegister(0));                                 \ | 
| +    __ cbnz(i.TempRegister32(1), &binop);                              \ | 
| +  } while (0) | 
| + | 
| #define ASSEMBLE_IEEE754_BINOP(name)                                          \ | 
| do {                                                                        \ | 
| FrameScope scope(masm(), StackFrame::MANUAL);                             \ | 
| @@ -1696,6 +1709,30 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction( | 
| __ mov(i.TempRegister(1), i.InputRegister(2)); | 
| ASSEMBLE_ATOMIC_COMPARE_EXCHANGE_INTEGER(ldaxr, stlxr); | 
| break; | 
| +#define ATOMIC_BINOP_CASE(op, inst)                    \ | 
| +  case kAtomic##op##Int8:                              \ | 
| +    ASSEMBLE_ATOMIC_BINOP(ldaxrb, stlxrb, inst);       \ | 
| +    __ Sxtb(i.OutputRegister(0), i.OutputRegister(0)); \ | 
| +    break;                                             \ | 
| +  case kAtomic##op##Uint8:                             \ | 
| +    ASSEMBLE_ATOMIC_BINOP(ldaxrb, stlxrb, inst);       \ | 
| +    break;                                             \ | 
| +  case kAtomic##op##Int16:                             \ | 
| +    ASSEMBLE_ATOMIC_BINOP(ldaxrh, stlxrh, inst);       \ | 
| +    __ Sxth(i.OutputRegister(0), i.OutputRegister(0)); \ | 
| +    break;                                             \ | 
| +  case kAtomic##op##Uint16:                            \ | 
| +    ASSEMBLE_ATOMIC_BINOP(ldaxrh, stlxrh, inst);       \ | 
| +    break;                                             \ | 
| +  case kAtomic##op##Word32:                            \ | 
| +    ASSEMBLE_ATOMIC_BINOP(ldaxr, stlxr, inst);         \ | 
| +    break; | 
| +      ATOMIC_BINOP_CASE(Add, Add) | 
| +      ATOMIC_BINOP_CASE(Sub, Sub) | 
| +      ATOMIC_BINOP_CASE(And, And) | 
| +      ATOMIC_BINOP_CASE(Or, Orr) | 
| +      ATOMIC_BINOP_CASE(Xor, Eor) | 
| +#undef ATOMIC_BINOP_CASE | 
| } | 
| return kSuccess; | 
| }  // NOLINT(readability/fn_size) | 
|  |