Add ToBoolean-conversion of constants in Crankshaft and use it when generating a branch based on ...

src/hydrogen-instructions.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 1032 matching lines @@
 
 
 HConstant* HConstant::CopyToTruncatedInt32() const {
   if (!has_double_value_) return NULL;
   int32_t truncated = NumberToInt32(*handle_);
   return new HConstant(FACTORY->NewNumberFromInt(truncated),
                        Representation::Integer32());
 }
 
 
+bool HConstant::ToBoolean() const {
+  // Converts the constant's boolean value according to
+  // ECMAScript section 9.2 ToBoolean conversion.
+  if (HasInteger32Value()) return Integer32Value() != 0;
+  if (HasDoubleValue()) {
+    double v = DoubleValue();
+    return v != 0 && !isnan(v);
+  }
+  if (handle()->IsTrue()) return true;
+  if (handle()->IsFalse()) return false;
+  if (handle()->IsUndefined()) return false;
+  if (handle()->IsNull()) return false;
+  if (handle()->IsString() &&
+      String::cast(*handle())->length() == 0) return false;
+  return true;
+}
+
 void HConstant::PrintDataTo(StringStream* stream) {
   handle()->ShortPrint(stream);
 }
 
 
 bool HArrayLiteral::IsCopyOnWrite() const {
   return constant_elements()->map() == HEAP->fixed_cow_array_map();
 }
 
 
@@ skipping 567 matching lines @@
 
 
 void HCheckPrototypeMaps::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal