[Atomics] Make Atomics.exchange a builtin using TF

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 6b4ee00a56c103fc67661cdf1313ad3fd2e14ba4..3a4847b9a4c92bd47fc6641f11989b198a887aca 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -2135,24 +2135,6 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       }
       break;
     }
-    case kX64Xchgb: {
-      size_t index = 0;
-      Operand operand = i.MemoryOperand(&index);
-      __ xchgb(i.InputRegister(index), operand);
-      break;
-    }
-    case kX64Xchgw: {
-      size_t index = 0;
-      Operand operand = i.MemoryOperand(&index);
-      __ xchgw(i.InputRegister(index), operand);
-      break;
-    }
-    case kX64Xchgl: {
-      size_t index = 0;
-      Operand operand = i.MemoryOperand(&index);
-      __ xchgl(i.InputRegister(index), operand);
-      break;
-    }
     case kX64Int32x4Create: {
       CpuFeatureScope sse_scope(masm(), SSE4_1);
       XMMRegister dst = i.OutputSimd128Register();
@@ -2230,6 +2212,40 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kX64StackCheck:
       __ CompareRoot(rsp, Heap::kStackLimitRootIndex);
       break;
+#define EXCHANGE_OPERANDS                \
+  size_t index = 0;                      \
+  Register r = i.InputRegister(index++); \

[binji, 2017/02/22 02:08:38]

same comment here as for ia32

[aseemgarg, 2017/02/22 03:29:02]

Done.

+  Operand operand = i.MemoryOperand(&index);
+    case kAtomicExchangeInt8: {
+      EXCHANGE_OPERANDS
+      __ xchgb(r, operand);
+      __ movsxbl(r, r);
+      break;
+    }
+    case kAtomicExchangeUint8: {
+      EXCHANGE_OPERANDS
+      __ xchgb(r, operand);
+      __ movzxbl(r, r);
+      break;
+    }
+    case kAtomicExchangeInt16: {
+      EXCHANGE_OPERANDS
+      __ xchgw(r, operand);
+      __ movsxwl(r, r);
+      break;
+    }
+    case kAtomicExchangeUint16: {
+      EXCHANGE_OPERANDS
+      __ xchgw(r, operand);
+      __ movzxwl(r, r);
+      break;
+    }
+    case kAtomicExchangeWord32: {
+      EXCHANGE_OPERANDS
+      __ xchgl(r, operand);
+      break;
+    }
+#undef EXCHANGE_OPERANDS
     case kAtomicLoadInt8:
     case kAtomicLoadUint8:
     case kAtomicLoadInt16: