192   }
 193   return v == NULL;
 194 }
 195 
 196 void Canonicalizer::do_StoreField     (StoreField*      x) {
 197   // If a value is going to be stored into a field or array some of
 198   // the conversions emitted by javac are unneeded because the fields
 199   // are packed to their natural size.
 200   Convert* conv = x->value()->as_Convert();
 201   if (conv) {
 202     Value value = NULL;
 203     BasicType type = x->field()->type()->basic_type();
 204     switch (conv->op()) {
 205     case Bytecodes::_i2b: if (type == T_BYTE)  value = conv->value(); break;
 206     case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
 207     case Bytecodes::_i2c: if (type == T_CHAR  || type == T_BYTE)  value = conv->value(); break;
 208     }
 209     // limit this optimization to current block
 210     if (value != NULL && in_current_block(conv)) {
 211       set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
 212                                        x->state_before(), x->is_loaded(), x->is_initialized()));
 213       return;
 214     }
 215   }
 216 
 217 }
 218 
 219 void Canonicalizer::do_ArrayLength    (ArrayLength*     x) {
 220   NewArray* array = x->array()->as_NewArray();
 221   if (array != NULL && array->length() != NULL) {
 222     Constant* length = array->length()->as_Constant();
 223     if (length != NULL) {
 224       // do not use the Constant itself, but create a new Constant
 225       // with same value Otherwise a Constant is live over multiple
 226       // blocks without being registered in a state array.
 227       assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
 228       set_constant(length->type()->as_IntConstant()->value());
 229     }
 230   } else {
 231     LoadField* lf = x->array()->as_LoadField();
 232     if (lf != NULL) {

 192   }
 193   return v == NULL;
 194 }
 195 
 196 void Canonicalizer::do_StoreField     (StoreField*      x) {
 197   // If a value is going to be stored into a field or array some of
 198   // the conversions emitted by javac are unneeded because the fields
 199   // are packed to their natural size.
 200   Convert* conv = x->value()->as_Convert();
 201   if (conv) {
 202     Value value = NULL;
 203     BasicType type = x->field()->type()->basic_type();
 204     switch (conv->op()) {
 205     case Bytecodes::_i2b: if (type == T_BYTE)  value = conv->value(); break;
 206     case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
 207     case Bytecodes::_i2c: if (type == T_CHAR  || type == T_BYTE)  value = conv->value(); break;
 208     }
 209     // limit this optimization to current block
 210     if (value != NULL && in_current_block(conv)) {
 211       set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
 212                                    x->state_before(), x->needs_patching()));
 213       return;
 214     }
 215   }
 216 
 217 }
 218 
 219 void Canonicalizer::do_ArrayLength    (ArrayLength*     x) {
 220   NewArray* array = x->array()->as_NewArray();
 221   if (array != NULL && array->length() != NULL) {
 222     Constant* length = array->length()->as_Constant();
 223     if (length != NULL) {
 224       // do not use the Constant itself, but create a new Constant
 225       // with same value Otherwise a Constant is live over multiple
 226       // blocks without being registered in a state array.
 227       assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
 228       set_constant(length->type()->as_IntConstant()->value());
 229     }
 230   } else {
 231     LoadField* lf = x->array()->as_LoadField();
 232     if (lf != NULL) {