Put a slow assert under the enable_slow_asserts flag.

src/full-codegen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 352 matching lines @@
 
 
 void FullCodeGenerator::PrepareForBailoutForId(unsigned id, State state) {
   // There's no need to prepare this code for bailouts from already optimized
   // code or code that can't be optimized.
   if (!FLAG_deopt || !info_->HasDeoptimizationSupport()) return;
   unsigned pc_and_state =
       StateField::encode(state) | PcField::encode(masm_->pc_offset());
   BailoutEntry entry = { id, pc_and_state };
 #ifdef DEBUG
-  // Assert that we don't have multiple bailout entries for the same node.
-  for (int i = 0; i < bailout_entries_.length(); i++) {
-    if (bailout_entries_.at(i).id == entry.id) {
-      AstPrinter printer;
-      PrintF("%s", printer.PrintProgram(info_->function()));
-      UNREACHABLE();
+  if (FLAG_enable_slow_asserts) {
+    // Assert that we don't have multiple bailout entries for the same node.
+    for (int i = 0; i < bailout_entries_.length(); i++) {
+      if (bailout_entries_.at(i).id == entry.id) {
+        AstPrinter printer;
+        PrintF("%s", printer.PrintProgram(info_->function()));
+        UNREACHABLE();
+      }
     }
   }
 #endif  // DEBUG
   bailout_entries_.Add(entry);
 }
 
 
 void FullCodeGenerator::RecordStackCheck(unsigned ast_id) {
   // The pc offset does not need to be encoded and packed together with a
   // state.
@@ skipping 913 matching lines @@
   }
 
   return false;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal