| Index: src/compiler/s390/code-generator-s390.cc | 
| diff --git a/src/compiler/s390/code-generator-s390.cc b/src/compiler/s390/code-generator-s390.cc | 
| index 0b531aa036ae26564efda860c89c6e081d77ee1a..348bdd20c9abbefd5b95201b4adfbb17fc2c1cf4 100644 | 
| --- a/src/compiler/s390/code-generator-s390.cc | 
| +++ b/src/compiler/s390/code-generator-s390.cc | 
| @@ -2414,6 +2414,14 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction( | 
| __ bne(&do_cs, Label::kNear); | 
| break; | 
| } | 
| +    case kAtomicCompareExchangeInt8: | 
| +    case kAtomicCompareExchangeUint8: | 
| +    case kAtomicCompareExchangeInt16: | 
| +    case kAtomicCompareExchangeUint16: | 
| +    case kAtomicCompareExchangeWord32: { | 
| +      UNREACHABLE(); | 
| +      break; | 
| +    } | 
| default: | 
| UNREACHABLE(); | 
| break; | 
|  |