[Atomics] Make Atomics.compareExchange a builtin using TF

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index cfc1841bac507e11b23295d393814faa12151491..e3172470513b1da08e16e43243a581ea48766698 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -2314,6 +2314,48 @@ void InstructionSelector::VisitAtomicExchange(Node* node) {
   Emit(code, 1, outputs, input_count, inputs);
 }
 
+void InstructionSelector::VisitAtomicCompareExchange(Node* node) {
+  X64OperandGenerator g(this);
+  Node* base = node->InputAt(0);
+  Node* index = node->InputAt(1);
+  Node* old_value = node->InputAt(2);
+  Node* new_value = node->InputAt(3);
+
+  MachineType type = AtomicCompareExchangeRepresentationOf(node->op());
+  ArchOpcode opcode = kArchNop;
+  if (type == MachineType::Int8()) {
+    opcode = kAtomicCompareExchangeInt8;
+  } else if (type == MachineType::Uint8()) {
+    opcode = kAtomicCompareExchangeUint8;
+  } else if (type == MachineType::Int16()) {
+    opcode = kAtomicCompareExchangeInt16;
+  } else if (type == MachineType::Uint16()) {
+    opcode = kAtomicCompareExchangeUint16;
+  } else if (type == MachineType::Int32() || type == MachineType::Uint32()) {
+    opcode = kAtomicCompareExchangeWord32;
+  } else {
+    UNREACHABLE();
+    return;
+  }
+  InstructionOperand outputs[1];
+  AddressingMode addressing_mode;
+  InstructionOperand inputs[4];
+  size_t input_count = 0;
+  inputs[input_count++] = g.UseFixed(old_value, rax);
+  inputs[input_count++] = g.UseUniqueRegister(new_value);
+  inputs[input_count++] = g.UseUniqueRegister(base);
+  if (g.CanBeImmediate(index)) {
+    inputs[input_count++] = g.UseImmediate(index);
+    addressing_mode = kMode_MRI;
+  } else {
+    inputs[input_count++] = g.UseUniqueRegister(index);
+    addressing_mode = kMode_MR1;
+  }
+  outputs[0] = g.DefineAsFixed(node, rax);
+  InstructionCode code = opcode | AddressingModeField::encode(addressing_mode);
+  Emit(code, 1, outputs, input_count, inputs);
+}
+
 void InstructionSelector::VisitInt32x4Splat(Node* node) {
   X64OperandGenerator g(this);
   Emit(kX64Int32x4Splat, g.DefineAsRegister(node), g.Use(node->InputAt(0)));