[Atomics] use TFJ builtins for atomic add, sub, and, or, and xor

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 2411 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 529 matching lines @@
       padding_size -= 2;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8