1 /*

     2  * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #include "precompiled.hpp"

    26 #include "memory/allocation.inline.hpp"

    27 #include "opto/addnode.hpp"

    28 #include "opto/machnode.hpp"

    29 #include "opto/mathexactnode.hpp"

    30 #include "opto/matcher.hpp"

    31 #include "opto/subnode.hpp"

    32 

    33 MathExactNode::MathExactNode(Node* ctrl, Node* n1, Node* n2) : MultiNode(3) {

    34   init_req(0, ctrl);

    35   init_req(1, n1);

    36   init_req(2, n2);

    37 }

    38 

    39 Node* AddExactINode::match(const ProjNode* proj, const Matcher* m) {

    40   uint ideal_reg = proj->ideal_reg();

    41   RegMask rm;

    42   if (proj->_con == result_proj_node) {

    43     rm = m->mathExactI_result_proj_mask();

    44   } else {

    45     assert(proj->_con == flags_proj_node, "must be result or flags");

    46     assert(ideal_reg == Op_RegFlags, "sanity");

    47     rm = m->mathExactI_flags_proj_mask();

    48   }

    49   return new (m->C) MachProjNode(this, proj->_con, rm, ideal_reg);

    50 }

    51 

    52 // If the MathExactNode won't overflow we have to replace the

    53 // FlagsProjNode and ProjNode that is generated by the MathExactNode

    54 Node* MathExactNode::no_overflow(PhaseGVN *phase, Node* new_result) {

    55   PhaseIterGVN *igvn = phase->is_IterGVN();

    56   if (igvn) {

    57     ProjNode* result = result_node();

    58     ProjNode* flags = flags_node();

    59 

    60     if (result != NULL) {

    61       igvn->replace_node(result, new_result);

    62     }

    63 

    64     if (flags != NULL) {

    65       BoolNode* bolnode = (BoolNode *) flags->unique_out();

    66       switch (bolnode->_test._test) {

    67         case BoolTest::overflow:

    68           // if the check is for overflow - never taken

    69           igvn->replace_node(bolnode, phase->intcon(0));

    70           break;

    71         case BoolTest::no_overflow:

    72           // if the check is for no overflow - always taken

    73           igvn->replace_node(bolnode, phase->intcon(1));

    74           break;

    75         default:

    76           fatal("Unexpected value of BoolTest");

    77           break;

    78       }

    79       flags->del_req(0);

    80     }

    81   }

    82   return new_result;

    83 }

    84 

    85 Node *AddExactINode::Ideal(PhaseGVN *phase, bool can_reshape) {

    86   Node *arg1 = in(1);

    87   Node *arg2 = in(2);

    88 

    89   const Type* type1 = phase->type(arg1);

    90   const Type* type2 = phase->type(arg2);

    91 

    92   if (type1 != Type::TOP && type1->singleton() &&

    93       type2 != Type::TOP && type2->singleton()) {

    94     jint val1 = arg1->get_int();

    95     jint val2 = arg2->get_int();

    96     jint result = val1 + val2;

    97     // Hacker's Delight 2-12 Overflow if both arguments have the opposite sign of the result

    98     if ( (((val1 ^ result) & (val2 ^ result)) >= 0)) {

    99       Node* con_result = ConINode::make(phase->C, result);

   100       return no_overflow(phase, con_result);

   101     }

   102     return NULL;

   103   }

   104 

   105   if (type1 == TypeInt::ZERO) { // (Add 0 x) == x

   106     Node* add_result = new (phase->C) AddINode(arg1, arg2);

   107     return no_overflow(phase, add_result);

   108   }

   109 

   110   if (type2 == TypeInt::ZERO) { // (Add x 0) == x

   111     Node* add_result = new (phase->C) AddINode(arg1, arg2);

   112     return no_overflow(phase, add_result);

   113   }

   114 

   115   if (type2->singleton()) {

   116     return NULL; // no change - keep constant on the right

   117   }

   118 

   119   if (type1->singleton()) {

   120     // Make it x + Constant - move constant to the right

   121     swap_edges(1, 2);

   122     return this;

   123   }

   124 

   125   if (arg2->is_Load()) {

   126     return NULL; // no change - keep load on the right

   127   }

   128 

   129   if (arg1->is_Load()) {

   130     // Make it x + Load - move load to the right

   131     swap_edges(1, 2);

   132     return this;

   133   }

   134 

   135   if (arg1->_idx > arg2->_idx) {

   136     // Sort the edges

   137     swap_edges(1, 2);

   138     return this;

   139   }

   140 

   141   return NULL;

   142 }

   143