Ensure constant truncation is only done when it is safe.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 3c4482547a2af701f56c740e047a4d8e287d7105..e93e21d99fde5c183208c9a0b7144a0aecdf2de3 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2575,25 +2575,23 @@ Maybe<HConstant*> HConstant::CopyToTruncatedInt32(Zone* zone) {
                               Representation::Integer32(),
                               is_not_in_new_space_,
                               handle_);
-  } else {
-    ASSERT(!HasNumberValue());
-    Maybe<HConstant*> number = CopyToTruncatedNumber(zone);
-    if (number.has_value) return number.value->CopyToTruncatedInt32(zone);
   }
   return Maybe<HConstant*>(res != NULL, res);
 }
 
 
-Maybe<HConstant*> HConstant::CopyToTruncatedNumber(Zone* zone) {
+Maybe<HConstant*> HConstant::CopyToTruncatedNumberAndAdd(
+    Zone* zone, HGraphBuilder* builder) {

[Michael Starzinger, 2013/09/17 12:10:13]

I don't like passing around the HGraphBuilder into HInstructions. I see that
this would give static guarantees that no-one introduces call to this method
outside the graph builder, but it destroys decoupling please revert this part of
the change and just keep the fix in HConstant::CopyToTruncatedInt32.

   HConstant* res = NULL;
   Handle<Object> handle = this->handle(zone->isolate());
   if (handle->IsBoolean()) {
-    res = handle->BooleanValue() ?
-      new(zone) HConstant(1) : new(zone) HConstant(0);
+    res = handle->BooleanValue()
+      ? builder->graph()->GetConstant1()
+      : builder->graph()->GetConstant0();
   } else if (handle->IsUndefined()) {
-    res = new(zone) HConstant(OS::nan_value());
+    res = builder->Add<HConstant>(OS::nan_value());
   } else if (handle->IsNull()) {
-    res = new(zone) HConstant(0);
+    res = builder->graph()->GetConstant0();
   }
   return Maybe<HConstant*>(res != NULL, res);
 }