Cut-and-paste port from ia32 to x64: Delay load of trivial left operand of binary operation until after right operand loaded.

Review URL: http://codereview.chromium.org/1736023

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4552 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/codegen-x64.cc

@@ -3531,8 +3531,15 @@ void CodeGenerator::VisitBinaryOperation(BinaryOperation* node) {
       overwrite_mode = OVERWRITE_RIGHT;
     }
 
-    Load(node->left());
-    Load(node->right());
+    if (node->left()->IsTrivial()) {
+      Load(node->right());
+      Result right = frame_->Pop();
+      frame_->Push(node->left());
+      frame_->Push(&right);
+    } else {
+      Load(node->left());
+      Load(node->right());
+    }
     GenericBinaryOperation(node->op(), node->type(), overwrite_mode);
   }
 }

src/x64/virtual-frame-x64.cc

@@ -226,6 +226,31 @@ void VirtualFrame::EmitPush(Heap::RootListIndex index, TypeInfo info) {
 }
 
 
+void VirtualFrame::Push(Expression* expr) {
+  ASSERT(expr->IsTrivial());
+
+  Literal* lit = expr->AsLiteral();
+  if (lit != NULL) {
+    Push(lit->handle());
+    return;
+  }
+
+  VariableProxy* proxy = expr->AsVariableProxy();
+  if (proxy != NULL) {
+    Slot* slot = proxy->var()->slot();
+    if (slot->type() == Slot::LOCAL) {
+      PushLocalAt(slot->index());
+      return;
+    }
+    if (slot->type() == Slot::PARAMETER) {
+      PushParameterAt(slot->index());
+      return;
+    }
+  }
+  UNREACHABLE();
+}
+
+
 void VirtualFrame::Drop(int count) {
   ASSERT(count >= 0);
   ASSERT(height() >= count);

src/x64/virtual-frame-x64.h

@@ -415,6 +415,10 @@ class VirtualFrame : public ZoneObject {
     result->Unuse();
   }
 
+  // Pushing an expression expects that the expression is trivial (according
+  // to Expression::IsTrivial).
+  void Push(Expression* expr);
+
   // Nip removes zero or more elements from immediately below the top
   // of the frame, leaving the previous top-of-frame value on top of
   // the frame.  Nip(k) is equivalent to x = Pop(), Drop(k), Push(x).