1648 if (rc == NULL || phase->type(rc) == Type::TOP) {
1649 if (n != top) { // Not already top?
1650 PhaseIterGVN *igvn = phase->is_IterGVN();
1651 if (can_reshape && igvn != NULL) {
1652 igvn->_worklist.push(r);
1653 }
1654 set_req(j, top); // Nuke it down
1655 progress = this; // Record progress
1656 }
1657 }
1658 }
1659
1660 if (can_reshape && outcnt() == 0) {
1661 // set_req() above may kill outputs if Phi is referenced
1662 // only by itself on the dead (top) control path.
1663 return top;
1664 }
1665
1666 bool uncasted = false;
1667 Node* uin = unique_input(phase, false);
1668 if (uin == NULL) {
1669 uncasted = true;
1670 uin = unique_input(phase, true);
1671 }
1672 if (uin == top) { // Simplest case: no alive inputs.
1673 if (can_reshape) // IGVN transformation
1674 return top;
1675 else
1676 return NULL; // Identity will return TOP
1677 } else if (uin != NULL) {
1678 // Only one not-NULL unique input path is left.
1679 // Determine if this input is backedge of a loop.
1680 // (Skip new phis which have no uses and dead regions).
1681 if (outcnt() > 0 && r->in(0) != NULL) {
1682 // First, take the short cut when we know it is a loop and
1683 // the EntryControl data path is dead.
1684 // Loop node may have only one input because entry path
1685 // is removed in PhaseIdealLoop::Dominators().
1686 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs");
1687 bool is_loop = (r->is_Loop() && r->req() == 3);
1688 // Then, check if there is a data loop when phi references itself directly
1689 // or through other data nodes.
1690 if (is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl)) ||
1691 !is_loop && is_unsafe_data_reference(uin)) {
1692 // Break this data loop to avoid creation of a dead loop.
1693 if (can_reshape) {
1694 return top;
1695 } else {
1696 // We can't return top if we are in Parse phase - cut inputs only
1697 // let Identity to handle the case.
1698 replace_edge(uin, top);
1699 return NULL;
1700 }
1701 }
1702 }
1703
1704 if (uncasted) {
1705 const Type* phi_type = bottom_type();
1706 assert(phi_type->isa_int() || phi_type->isa_ptr(), "bad phi type");
1707 int opcode;
1708 if (phi_type->isa_int()) {
1709 opcode = Op_CastII;
1710 } else {
1711 const Type* uin_type = phase->type(uin);
1712 if (phi_type->join(TypePtr::NOTNULL) == uin_type->join(TypePtr::NOTNULL)) {
1713 opcode = Op_CastPP;
1714 } else {
1715 opcode = Op_CheckCastPP;
1716 }
1717 }
1718 // Add a cast to carry the control dependency of the Phi that is
1719 // going away
1720 Node* cast = ConstraintCastNode::make_cast(opcode, r, uin, phi_type, true);
1721 cast = phase->transform(cast);
1722 // set all inputs to the new cast so the Phi is removed by Identity
1723 for (uint i = 1; i < req(); i++) {
1724 set_req(i, cast);
1725 }
1726 uin = cast;
1727 }
1728
1729 // One unique input.
1730 debug_only(Node* ident = Identity(phase));
1731 // The unique input must eventually be detected by the Identity call.
1732 #ifdef ASSERT
1733 if (ident != uin && !ident->is_top()) {
1734 // print this output before failing assert
1735 r->dump(3);
1736 this->dump(3);
1737 ident->dump();
1738 uin->dump();
1739 }
1740 #endif
1741 assert(ident == uin || ident->is_top(), "Identity must clean this up");
1742 return NULL;
1743 }
1744
|
1648 if (rc == NULL || phase->type(rc) == Type::TOP) {
1649 if (n != top) { // Not already top?
1650 PhaseIterGVN *igvn = phase->is_IterGVN();
1651 if (can_reshape && igvn != NULL) {
1652 igvn->_worklist.push(r);
1653 }
1654 set_req(j, top); // Nuke it down
1655 progress = this; // Record progress
1656 }
1657 }
1658 }
1659
1660 if (can_reshape && outcnt() == 0) {
1661 // set_req() above may kill outputs if Phi is referenced
1662 // only by itself on the dead (top) control path.
1663 return top;
1664 }
1665
1666 bool uncasted = false;
1667 Node* uin = unique_input(phase, false);
1668 if (uin == NULL && can_reshape) {
1669 uncasted = true;
1670 uin = unique_input(phase, true);
1671 }
1672 if (uin == top) { // Simplest case: no alive inputs.
1673 if (can_reshape) // IGVN transformation
1674 return top;
1675 else
1676 return NULL; // Identity will return TOP
1677 } else if (uin != NULL) {
1678 // Only one not-NULL unique input path is left.
1679 // Determine if this input is backedge of a loop.
1680 // (Skip new phis which have no uses and dead regions).
1681 if (outcnt() > 0 && r->in(0) != NULL) {
1682 // First, take the short cut when we know it is a loop and
1683 // the EntryControl data path is dead.
1684 // Loop node may have only one input because entry path
1685 // is removed in PhaseIdealLoop::Dominators().
1686 assert(!r->is_Loop() || r->req() <= 3, "Loop node should have 3 or less inputs");
1687 bool is_loop = (r->is_Loop() && r->req() == 3);
1688 // Then, check if there is a data loop when phi references itself directly
1689 // or through other data nodes.
1690 if (is_loop && !uin->eqv_uncast(in(LoopNode::EntryControl)) ||
1691 !is_loop && is_unsafe_data_reference(uin)) {
1692 // Break this data loop to avoid creation of a dead loop.
1693 if (can_reshape) {
1694 return top;
1695 } else {
1696 // We can't return top if we are in Parse phase - cut inputs only
1697 // let Identity to handle the case.
1698 replace_edge(uin, top);
1699 return NULL;
1700 }
1701 }
1702 }
1703
1704 if (uncasted) {
1705 // Wait until after parsing for the type information to propagate from the casts
1706 assert(can_reshape, "Invalid during parsing");
1707 const Type* phi_type = bottom_type();
1708 assert(phi_type->isa_int() || phi_type->isa_ptr(), "bad phi type");
1709 int opcode;
1710 if (phi_type->isa_int()) {
1711 opcode = Op_CastII;
1712 } else {
1713 const Type* uin_type = phase->type(uin);
1714 if (phi_type->join(TypePtr::NOTNULL) == uin_type->join(TypePtr::NOTNULL)) {
1715 opcode = Op_CastPP;
1716 } else {
1717 opcode = Op_CheckCastPP;
1718 }
1719 }
1720 // Add a cast to carry the control dependency of the Phi that is
1721 // going away
1722 Node* cast = ConstraintCastNode::make_cast(opcode, r, uin, phi_type, true);
1723 cast = phase->transform(cast);
1724 // set all inputs to the new cast so the Phi is removed by Identity
1725 PhaseIterGVN* igvn = phase->is_IterGVN();
1726 for (uint i = 1; i < req(); i++) {
1727 set_req_X(i, cast, igvn);
1728 }
1729 uin = cast;
1730 }
1731
1732 // One unique input.
1733 debug_only(Node* ident = Identity(phase));
1734 // The unique input must eventually be detected by the Identity call.
1735 #ifdef ASSERT
1736 if (ident != uin && !ident->is_top()) {
1737 // print this output before failing assert
1738 r->dump(3);
1739 this->dump(3);
1740 ident->dump();
1741 uin->dump();
1742 }
1743 #endif
1744 assert(ident == uin || ident->is_top(), "Identity must clean this up");
1745 return NULL;
1746 }
1747
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