static bool match(UnsafeRawOp* x,
Instruction** base,
Instruction** index,
int* log2_scale) {
Instruction* instr_to_unpin = NULL;
ArithmeticOp* root = x->base()->as_ArithmeticOp();
if (root == NULL) return false;
// Limit ourselves to addition for now
if (root->op() != Bytecodes::_ladd) return false;
// Try to find shift or scale op
if (match_index_and_scale(root->y(), index, log2_scale, &instr_to_unpin)) {
*base = root->x();
} else if (match_index_and_scale(root->x(), index, log2_scale, &instr_to_unpin)) {
*base = root->y();
} else if (root->y()->as_Convert() != NULL) {
Convert* convert = root->y()->as_Convert();
if (convert->op() == Bytecodes::_i2l && convert->value()->type() == intType) {
// pick base and index, setting scale at 1
*base = root->x();
*index = convert->value();
*log2_scale = 0;
} else {
return false;
}
} else {
// doesn't match any expected sequences
return false;
}
// Typically the addition is pinned, as it is the result of an
// inlined routine. We want to unpin it so as to avoid the long
// addition, but in order to do so we must still ensure that the
// operands are pinned, as they may be computed arbitrarily before
// the Unsafe op completes (even if the Unsafe op is pinned). At
// this point we do not really need to pin Unsafe raw or object
// gets.
if (root->is_pinned()) {
if (root->pin_state() == Instruction::PinInlineReturnValue) {
assert(x->is_pinned(), "All unsafe raw ops should be pinned");
root->unpin(Instruction::PinInlineReturnValue);
(*base)->pin();
(*index)->pin();
} else {
// can't safely unpin this instruction
return false;
}
}
if (PrintUnsafeOptimization && instr_to_unpin != NULL) {
tty->print_cr("pin_state = 0x%x", instr_to_unpin->pin_state());
instr_to_unpin->print();
}
return true;
}
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;
}