[turbofan] Implement OSR for outer loops.

src/runtime/runtime-compiler.cc

Index: src/runtime/runtime-compiler.cc
diff --git a/src/runtime/runtime-compiler.cc b/src/runtime/runtime-compiler.cc
index ebd0c13f0f9b1ef2e2bb44d5bfcb4d017d5e041c..37e17862fa60fa6c62a4d0825be8607ddb2cbf71 100644
--- a/src/runtime/runtime-compiler.cc
+++ b/src/runtime/runtime-compiler.cc
@@ -290,8 +290,15 @@ RUNTIME_FUNCTION(Runtime_CompileForOnStackReplacement) {
       // match. Fix heuristics for reenabling optimizations!
       function->shared()->increment_deopt_count();
 
-      // TODO(titzer): Do not install code into the function.
-      function->ReplaceCode(*result);
+      if (result->is_turbofanned()) {
+        // TurboFanned OSR code cannot be installed into the function.
+        // But the function is obviously hot, so optimize it next time.
+        function->ReplaceCode(
+            isolate->builtins()->builtin(Builtins::kCompileOptimized));
+      } else {
+        // Crankshafted OSR code can be installed into the function.
+        function->ReplaceCode(*result);
+      }
       return *result;
     }
   }