// perform constant and interval tests on index value
bool AccessIndexed::compute_needs_range_check() {
Constant* clength = length()->as_Constant();
Constant* cindex = index()->as_Constant();
if (clength && cindex) {
IntConstant* l = clength->type()->as_IntConstant();
IntConstant* i = cindex->type()->as_IntConstant();
if (l && i && i->value() < l->value() && i->value() >= 0) {
return false;
}
}
return true;
}
void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {
StableArrayConstant* array = x->array()->type()->as_StableArrayConstant();
IntConstant* index = x->index()->type()->as_IntConstant();
assert(array == NULL || FoldStableValues, "not enabled");
// Constant fold loads from stable arrays.
if (!x->mismatched() && array != NULL && index != NULL) {
jint idx = index->value();
if (idx < 0 || idx >= array->value()->length()) {
// Leave the load as is. The range check will handle it.
return;
}
ciConstant field_val = array->value()->element_value(idx);
if (!field_val.is_null_or_zero()) {
jint dimension = array->dimension();
assert(dimension <= array->value()->array_type()->dimension(), "inconsistent info");
ValueType* value = NULL;
if (dimension > 1) {
// Preserve information about the dimension for the element.
assert(field_val.as_object()->is_array(), "not an array");
value = new StableArrayConstant(field_val.as_object()->as_array(), dimension - 1);
} else {
assert(dimension == 1, "sanity");
value = as_ValueType(field_val);
}
set_canonical(new Constant(value));
}
}
}
void Canonicalizer::do_Intrinsic (Intrinsic* x) {
switch (x->id()) {
case ciMethod::_floatToRawIntBits : {
FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
if (c != NULL) {
JavaValue v;
v.set_jfloat(c->value());
set_constant(v.get_jint());
}
break;
}
case ciMethod::_intBitsToFloat : {
IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
if (c != NULL) {
JavaValue v;
v.set_jint(c->value());
set_constant(v.get_jfloat());
}
break;
}
case ciMethod::_doubleToRawLongBits : {
DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
if (c != NULL) {
JavaValue v;
v.set_jdouble(c->value());
set_constant(v.get_jlong());
}
break;
}
case ciMethod::_longBitsToDouble : {
LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
if (c != NULL) {
JavaValue v;
v.set_jlong(c->value());
set_constant(v.get_jdouble());
}
break;
}
}
}
static bool match_index_and_scale(Instruction* instr,
Instruction** index,
int* log2_scale,
Instruction** instr_to_unpin) {
*instr_to_unpin = NULL;
// Skip conversion ops
Convert* convert = instr->as_Convert();
if (convert != NULL) {
instr = convert->value();
}
ShiftOp* shift = instr->as_ShiftOp();
if (shift != NULL) {
if (shift->is_pinned()) {
*instr_to_unpin = shift;
}
// Constant shift value?
Constant* con = shift->y()->as_Constant();
if (con == NULL) return false;
// Well-known type and value?
IntConstant* val = con->type()->as_IntConstant();
if (val == NULL) return false;
if (shift->x()->type() != intType) return false;
*index = shift->x();
int tmp_scale = val->value();
if (tmp_scale >= 0 && tmp_scale < 4) {
*log2_scale = tmp_scale;
return true;
} else {
return false;
}
}
ArithmeticOp* arith = instr->as_ArithmeticOp();
if (arith != NULL) {
if (arith->is_pinned()) {
*instr_to_unpin = arith;
}
// Check for integer multiply
if (arith->op() == Bytecodes::_imul) {
// See if either arg is a known constant
Constant* con = arith->x()->as_Constant();
if (con != NULL) {
*index = arith->y();
} else {
con = arith->y()->as_Constant();
if (con == NULL) return false;
*index = arith->x();
}
if ((*index)->type() != intType) return false;
// Well-known type and value?
IntConstant* val = con->type()->as_IntConstant();
if (val == NULL) return false;
switch (val->value()) {
case 1: *log2_scale = 0; return true;
case 2: *log2_scale = 1; return true;
case 4: *log2_scale = 2; return true;
case 8: *log2_scale = 3; return true;
default: return false;
}
}
}
// Unknown instruction sequence; don't touch it
return false;
}
