X87: [turbofan] avoid xchg instruction on Intel.

src/compiler/x87/code-generator-x87.cc

Index: src/compiler/x87/code-generator-x87.cc
diff --git a/src/compiler/x87/code-generator-x87.cc b/src/compiler/x87/code-generator-x87.cc
index f4e334dbb2624ab5f417a86349e065b3836d4f91..ec8f80971fcf6feae47777e35fafd5e5622bef47 100644
--- a/src/compiler/x87/code-generator-x87.cc
+++ b/src/compiler/x87/code-generator-x87.cc
@@ -1915,10 +1915,19 @@ void CodeGenerator::AssembleSwap(InstructionOperand* source,
     // Register-register.
     Register src = g.ToRegister(source);
     Register dst = g.ToRegister(destination);
-    __ xchg(dst, src);
+    __ push(src);
+    __ mov(src, dst);
+    __ pop(dst);
   } else if (source->IsRegister() && destination->IsStackSlot()) {
     // Register-memory.
-    __ xchg(g.ToRegister(source), g.ToOperand(destination));
+    Register src = g.ToRegister(source);
+    __ push(src);
+    frame_access_state()->IncreaseSPDelta(1);
+    Operand dst = g.ToOperand(destination);
+    __ mov(src, dst);
+    frame_access_state()->IncreaseSPDelta(-1);
+    dst = g.ToOperand(destination);
+    __ pop(dst);
   } else if (source->IsStackSlot() && destination->IsStackSlot()) {
     // Memory-memory.
     Operand dst1 = g.ToOperand(destination);