[Atomics] Make Atomics.compareExchange a builtin using TF

src/compiler/s390/code-generator-s390.cc

 // Copyright 2015 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/code-generator.h"
 
 #include "src/compilation-info.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 2396 matching lines @@
       Register value = i.InputRegister(2);
       Register output = i.OutputRegister();
       Label do_cs;
       __ lay(r1, MemOperand(base, index));
       __ LoadlW(output, MemOperand(r1));
       __ bind(&do_cs);
       __ cs(output, value, MemOperand(r1));
       __ bne(&do_cs, Label::kNear);
       break;
     }
+    case kAtomicCompareExchangeInt8:
+    case kAtomicCompareExchangeUint8:
+    case kAtomicCompareExchangeInt16:
+    case kAtomicCompareExchangeUint16:
+    case kAtomicCompareExchangeWord32: {
+      UNREACHABLE();
+      break;
+    }
     default:
       UNREACHABLE();
       break;
   }
   return kSuccess;
 }  // NOLINT(readability/fn_size)
 
 // Assembles branches after an instruction.
 void CodeGenerator::AssembleArchBranch(Instruction* instr, BranchInfo* branch) {
   S390OperandConverter i(this, instr);
@@ skipping 525 matching lines @@
       padding_size -= 2;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8