Faster to number conversion

src/hydrogen-instructions.cc

 // Copyright 2012 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 2292 matching lines @@
                              unique_id_,
                              r,
                              type_from_value_,
                              is_internalized_string_,
                              is_not_in_new_space_,
                              is_cell_,
                              boolean_value_);
 }
 
 
-HConstant* HConstant::CopyToTruncatedInt32(Zone* zone) const {
+HConstant* HConstant::CopyToTruncatedInt32(Zone* zone) {
   if (has_int32_value_) {
     return new(zone) HConstant(int32_value_,
                                Representation::Integer32(),
                                is_not_in_new_space_,
                                handle_);
   }
   if (has_double_value_) {
     return new(zone) HConstant(DoubleToInt32(double_value_),
                                Representation::Integer32(),
                                is_not_in_new_space_,
                                handle_);
   }
+  HConstant* number = CopyToTruncatedNumber(zone);
+  return (number != NULL) ? number->CopyToTruncatedInt32(zone) : NULL;
+}
+
+
+HConstant* HConstant::CopyToTruncatedNumber(Zone* zone) {

[Toon Verwaest, 2013/07/22 08:31:44]

Shouldn't we also return "this" for values that are already numbers?

[oliv, 2013/07/22 13:56:43]

there is no point to copying the constant if we are already a number (since
unlike the int32 case we do not change representation).

returning 'this' is afaik not a good idea, since then the client does not know,
if the instruction was already added or not...

+  if (handle()->IsBoolean()) {
+    return handle()->BooleanValue() ?
+      new(zone) HConstant(1) : new(zone) HConstant(0);
+  } else if (handle()->IsUndefined()) {
+    return new(zone) HConstant(OS::nan_value());
+  } else if (handle()->IsNull()) {
+    return new(zone) HConstant(0);
+  }
   return NULL;
 }
 
 
 void HConstant::PrintDataTo(StringStream* stream) {
   if (has_int32_value_) {
     stream->Add("%d ", int32_value_);
   } else if (has_double_value_) {
     stream->Add("%f ", FmtElm(double_value_));
   } else {
@@ skipping 1658 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal