Avoid creating unnecessary branches in Hydrogen

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
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 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2726 matching lines @@
     }
     if (HChange::cast(value())->value()->type().IsSmi()) {
       return false;
     }
   }
   return true;
 }
 
 
 #define H_CONSTANT_INT32(val)                                                  \
-new(zone) HConstant(FACTORY->NewNumberFromInt(val, TENURED),                   \
-                    Representation::Integer32())
+new(zone) HConstant(val, Representation::Integer32())
 #define H_CONSTANT_DOUBLE(val)                                                 \
 new(zone) HConstant(FACTORY->NewNumber(val, TENURED),                          \

[Yang, 2013/02/19 14:39:07]

As discussed offline, there is no need to allocate in the double case either.

[Jakob Kummerow, 2013/02/21 08:46:26]

Done.

                     Representation::Double())
 
 #define DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR(HInstr, op)                       \
 HInstruction* HInstr::New##HInstr(Zone* zone,                                  \
                                   HValue* context,                             \
                                   HValue* left,                                \
                                   HValue* right) {                             \
   if (left->IsConstant() && right->IsConstant()) {                             \
     HConstant* c_left = HConstant::cast(left);                                 \
     HConstant* c_right = HConstant::cast(right);                               \
@@ skipping 125 matching lines @@
   if (left->IsConstant() && right->IsConstant()) {
     HConstant* c_left = HConstant::cast(left);
     HConstant* c_right = HConstant::cast(right);
     if ((c_left->HasNumberValue() && c_right->HasNumberValue())) {
       int32_t left_val = c_left->NumberValueAsInteger32();
       int32_t right_val = c_right->NumberValueAsInteger32() & 0x1f;
       if ((right_val == 0) && (left_val < 0)) {
         return H_CONSTANT_DOUBLE(
             static_cast<double>(static_cast<uint32_t>(left_val)));
       }
-      return H_CONSTANT_INT32(static_cast<uint32_t>(left_val) >> right_val);
+      return H_CONSTANT_INT32(static_cast<int32_t>(
+          static_cast<uint32_t>(left_val) >> right_val));
     }
   }
   return new(zone) HShr(context, left, right);
 }
 
 
 #undef H_CONSTANT_INT32
 #undef H_CONSTANT_DOUBLE
 
 
@@ skipping 153 matching lines @@
 
 
 void HCheckFunction::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal