Implement inlined stack-check guards in TurboFan.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index d0be3fecd113852c39879086d76a2fcbe78c48ab..09a8e018eb20a309e93bce003b0cd8ddfaf5a2d6 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -612,6 +612,8 @@ void InstructionSelector::VisitNode(Node* node) {
       return VisitFloat64LessThan(node);
     case IrOpcode::kFloat64LessThanOrEqual:
       return VisitFloat64LessThanOrEqual(node);
+    case IrOpcode::kLoadStackPointer:
+      return VisitLoadStackPointer(node);
     default:
       V8_Fatal(__FILE__, __LINE__, "Unexpected operator #%d:%s @ node #%d",
                node->opcode(), node->op()->mnemonic(), node->id());
@@ -727,6 +729,12 @@ void InstructionSelector::VisitFloat64LessThanOrEqual(Node* node) {
   VisitFloat64Compare(node, &cont);
 }
 
+
+void InstructionSelector::VisitLoadStackPointer(Node* node) {
+  OperandGenerator g(this);
+  Emit(kArchStackPointer, g.DefineAsRegister(node));
+}
+
 #endif  // V8_TURBOFAN_BACKEND
 
 // 32 bit targets do not implement the following instructions.