Strict mode poision pills.

src/x64/codegen-x64.cc

Index: src/x64/codegen-x64.cc
diff --git a/src/x64/codegen-x64.cc b/src/x64/codegen-x64.cc
index 21c90a1f164ddd56fa820b5c80aa85e7f675b30c..10aa4519f1b1f1cbb1d302da53672b24afd802f9 100644
--- a/src/x64/codegen-x64.cc
+++ b/src/x64/codegen-x64.cc
@@ -4260,9 +4260,10 @@ void CodeGenerator::InstantiateFunction(
 
   // Use the fast case closure allocation code that allocates in new
   // space for nested functions that don't need literals cloning.
-  if (scope()->is_function_scope() &&
+  if (!pretenure &&
+      scope()->is_function_scope() &&
       function_info->num_literals() == 0 &&
-      !pretenure) {
+      !function_info->strict_mode()) {  // Strict mode functions use slow path.
     FastNewClosureStub stub;
     frame_->Push(function_info);
     Result answer = frame_->CallStub(&stub, 1);