Allow uint32 value on optimized frames if they are consumed by safe operations.

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 6ac882da02262ecba4f646bf01123570b1026e6e..ccd94c7e71ebf0f29239a56df596ca551ab9c90f 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -218,6 +218,9 @@ DEFINE_int(loop_weight, 1, "loop weight for representation inference")
 
 DEFINE_bool(optimize_for_in, true,
             "optimize functions containing for-in loops")
+DEFINE_bool(opt_safe_uint32_operations, true,
+            "allow uint32 values on optimize frames if they are used only in"
+            "safe operations")
 
 DEFINE_bool(parallel_recompilation, false,
             "optimizing hot functions asynchronously on a separate thread")