0
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1 /*
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2 * Copyright 1998-2007 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #include "incls/_precompiled.incl"
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26 #include "incls/_loopnode.cpp.incl"
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27
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28 //=============================================================================
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29 //------------------------------is_loop_iv-------------------------------------
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30 // Determine if a node is Counted loop induction variable.
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31 // The method is declared in node.hpp.
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32 const Node* Node::is_loop_iv() const {
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33 if (this->is_Phi() && !this->as_Phi()->is_copy() &&
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34 this->as_Phi()->region()->is_CountedLoop() &&
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35 this->as_Phi()->region()->as_CountedLoop()->phi() == this) {
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36 return this;
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37 } else {
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38 return NULL;
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39 }
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40 }
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41
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42 //=============================================================================
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43 //------------------------------dump_spec--------------------------------------
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44 // Dump special per-node info
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45 #ifndef PRODUCT
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46 void LoopNode::dump_spec(outputStream *st) const {
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47 if( is_inner_loop () ) st->print( "inner " );
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48 if( is_partial_peel_loop () ) st->print( "partial_peel " );
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49 if( partial_peel_has_failed () ) st->print( "partial_peel_failed " );
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50 }
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51 #endif
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52
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53 //------------------------------get_early_ctrl---------------------------------
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54 // Compute earliest legal control
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55 Node *PhaseIdealLoop::get_early_ctrl( Node *n ) {
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56 assert( !n->is_Phi() && !n->is_CFG(), "this code only handles data nodes" );
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57 uint i;
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58 Node *early;
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59 if( n->in(0) ) {
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60 early = n->in(0);
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61 if( !early->is_CFG() ) // Might be a non-CFG multi-def
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62 early = get_ctrl(early); // So treat input as a straight data input
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63 i = 1;
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64 } else {
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65 early = get_ctrl(n->in(1));
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66 i = 2;
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67 }
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68 uint e_d = dom_depth(early);
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69 assert( early, "" );
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70 for( ; i < n->req(); i++ ) {
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71 Node *cin = get_ctrl(n->in(i));
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72 assert( cin, "" );
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73 // Keep deepest dominator depth
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74 uint c_d = dom_depth(cin);
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75 if( c_d > e_d ) { // Deeper guy?
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76 early = cin; // Keep deepest found so far
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77 e_d = c_d;
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78 } else if( c_d == e_d && // Same depth?
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79 early != cin ) { // If not equal, must use slower algorithm
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80 // If same depth but not equal, one _must_ dominate the other
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81 // and we want the deeper (i.e., dominated) guy.
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82 Node *n1 = early;
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83 Node *n2 = cin;
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84 while( 1 ) {
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85 n1 = idom(n1); // Walk up until break cycle
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86 n2 = idom(n2);
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87 if( n1 == cin || // Walked early up to cin
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88 dom_depth(n2) < c_d )
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89 break; // early is deeper; keep him
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90 if( n2 == early || // Walked cin up to early
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91 dom_depth(n1) < c_d ) {
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92 early = cin; // cin is deeper; keep him
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93 break;
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94 }
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95 }
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96 e_d = dom_depth(early); // Reset depth register cache
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97 }
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98 }
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99
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100 // Return earliest legal location
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101 assert(early == find_non_split_ctrl(early), "unexpected early control");
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102
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103 return early;
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104 }
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105
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106 //------------------------------set_early_ctrl---------------------------------
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107 // Set earliest legal control
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108 void PhaseIdealLoop::set_early_ctrl( Node *n ) {
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109 Node *early = get_early_ctrl(n);
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110
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111 // Record earliest legal location
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112 set_ctrl(n, early);
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113 }
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114
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115 //------------------------------set_subtree_ctrl-------------------------------
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116 // set missing _ctrl entries on new nodes
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117 void PhaseIdealLoop::set_subtree_ctrl( Node *n ) {
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118 // Already set? Get out.
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119 if( _nodes[n->_idx] ) return;
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120 // Recursively set _nodes array to indicate where the Node goes
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121 uint i;
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122 for( i = 0; i < n->req(); ++i ) {
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123 Node *m = n->in(i);
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124 if( m && m != C->root() )
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125 set_subtree_ctrl( m );
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126 }
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127
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128 // Fixup self
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129 set_early_ctrl( n );
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130 }
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131
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132 //------------------------------is_counted_loop--------------------------------
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133 Node *PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) {
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134 PhaseGVN *gvn = &_igvn;
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135
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136 // Counted loop head must be a good RegionNode with only 3 not NULL
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137 // control input edges: Self, Entry, LoopBack.
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138 if ( x->in(LoopNode::Self) == NULL || x->req() != 3 )
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139 return NULL;
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140
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141 Node *init_control = x->in(LoopNode::EntryControl);
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142 Node *back_control = x->in(LoopNode::LoopBackControl);
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143 if( init_control == NULL || back_control == NULL ) // Partially dead
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144 return NULL;
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145 // Must also check for TOP when looking for a dead loop
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146 if( init_control->is_top() || back_control->is_top() )
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147 return NULL;
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148
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149 // Allow funny placement of Safepoint
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150 if( back_control->Opcode() == Op_SafePoint )
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151 back_control = back_control->in(TypeFunc::Control);
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152
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153 // Controlling test for loop
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154 Node *iftrue = back_control;
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155 uint iftrue_op = iftrue->Opcode();
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156 if( iftrue_op != Op_IfTrue &&
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157 iftrue_op != Op_IfFalse )
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158 // I have a weird back-control. Probably the loop-exit test is in
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159 // the middle of the loop and I am looking at some trailing control-flow
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160 // merge point. To fix this I would have to partially peel the loop.
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161 return NULL; // Obscure back-control
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162
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163 // Get boolean guarding loop-back test
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164 Node *iff = iftrue->in(0);
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165 if( get_loop(iff) != loop || !iff->in(1)->is_Bool() ) return NULL;
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166 BoolNode *test = iff->in(1)->as_Bool();
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167 BoolTest::mask bt = test->_test._test;
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168 float cl_prob = iff->as_If()->_prob;
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169 if( iftrue_op == Op_IfFalse ) {
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170 bt = BoolTest(bt).negate();
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171 cl_prob = 1.0 - cl_prob;
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172 }
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173 // Get backedge compare
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174 Node *cmp = test->in(1);
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175 int cmp_op = cmp->Opcode();
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176 if( cmp_op != Op_CmpI )
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177 return NULL; // Avoid pointer & float compares
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178
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179 // Find the trip-counter increment & limit. Limit must be loop invariant.
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180 Node *incr = cmp->in(1);
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181 Node *limit = cmp->in(2);
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182
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183 // ---------
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184 // need 'loop()' test to tell if limit is loop invariant
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185 // ---------
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186
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187 if( !is_member( loop, get_ctrl(incr) ) ) { // Swapped trip counter and limit?
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188 Node *tmp = incr; // Then reverse order into the CmpI
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189 incr = limit;
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190 limit = tmp;
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191 bt = BoolTest(bt).commute(); // And commute the exit test
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192 }
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193 if( is_member( loop, get_ctrl(limit) ) ) // Limit must loop-invariant
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194 return NULL;
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195
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196 // Trip-counter increment must be commutative & associative.
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197 uint incr_op = incr->Opcode();
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198 if( incr_op == Op_Phi && incr->req() == 3 ) {
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199 incr = incr->in(2); // Assume incr is on backedge of Phi
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200 incr_op = incr->Opcode();
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201 }
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202 Node* trunc1 = NULL;
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203 Node* trunc2 = NULL;
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204 const TypeInt* iv_trunc_t = NULL;
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205 if (!(incr = CountedLoopNode::match_incr_with_optional_truncation(incr, &trunc1, &trunc2, &iv_trunc_t))) {
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206 return NULL; // Funny increment opcode
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207 }
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208
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209 // Get merge point
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210 Node *xphi = incr->in(1);
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211 Node *stride = incr->in(2);
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212 if( !stride->is_Con() ) { // Oops, swap these
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213 if( !xphi->is_Con() ) // Is the other guy a constant?
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214 return NULL; // Nope, unknown stride, bail out
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215 Node *tmp = xphi; // 'incr' is commutative, so ok to swap
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216 xphi = stride;
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217 stride = tmp;
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218 }
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219 //if( loop(xphi) != l) return NULL;// Merge point is in inner loop??
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220 if( !xphi->is_Phi() ) return NULL; // Too much math on the trip counter
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221 PhiNode *phi = xphi->as_Phi();
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222
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223 // Stride must be constant
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224 const Type *stride_t = stride->bottom_type();
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225 int stride_con = stride_t->is_int()->get_con();
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226 assert( stride_con, "missed some peephole opt" );
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227
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228 // Phi must be of loop header; backedge must wrap to increment
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229 if( phi->region() != x ) return NULL;
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230 if( trunc1 == NULL && phi->in(LoopNode::LoopBackControl) != incr ||
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231 trunc1 != NULL && phi->in(LoopNode::LoopBackControl) != trunc1 ) {
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232 return NULL;
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233 }
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234 Node *init_trip = phi->in(LoopNode::EntryControl);
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235 //if (!init_trip->is_Con()) return NULL; // avoid rolling over MAXINT/MININT
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236
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237 // If iv trunc type is smaller than int, check for possible wrap.
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238 if (!TypeInt::INT->higher_equal(iv_trunc_t)) {
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239 assert(trunc1 != NULL, "must have found some truncation");
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240
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241 // Get a better type for the phi (filtered thru if's)
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242 const TypeInt* phi_ft = filtered_type(phi);
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243
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244 // Can iv take on a value that will wrap?
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245 //
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246 // Ensure iv's limit is not within "stride" of the wrap value.
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247 //
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248 // Example for "short" type
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249 // Truncation ensures value is in the range -32768..32767 (iv_trunc_t)
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250 // If the stride is +10, then the last value of the induction
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251 // variable before the increment (phi_ft->_hi) must be
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252 // <= 32767 - 10 and (phi_ft->_lo) must be >= -32768 to
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253 // ensure no truncation occurs after the increment.
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254
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255 if (stride_con > 0) {
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256 if (iv_trunc_t->_hi - phi_ft->_hi < stride_con ||
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257 iv_trunc_t->_lo > phi_ft->_lo) {
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258 return NULL; // truncation may occur
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259 }
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260 } else if (stride_con < 0) {
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261 if (iv_trunc_t->_lo - phi_ft->_lo > stride_con ||
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262 iv_trunc_t->_hi < phi_ft->_hi) {
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263 return NULL; // truncation may occur
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264 }
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265 }
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266 // No possibility of wrap so truncation can be discarded
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267 // Promote iv type to Int
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268 } else {
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269 assert(trunc1 == NULL && trunc2 == NULL, "no truncation for int");
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270 }
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271
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272 // =================================================
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273 // ---- SUCCESS! Found A Trip-Counted Loop! -----
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274 //
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275 // Canonicalize the condition on the test. If we can exactly determine
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276 // the trip-counter exit value, then set limit to that value and use
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277 // a '!=' test. Otherwise use conditon '<' for count-up loops and
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278 // '>' for count-down loops. If the condition is inverted and we will
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279 // be rolling through MININT to MAXINT, then bail out.
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280
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281 C->print_method("Before CountedLoop", 3);
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282
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283 // Check for SafePoint on backedge and remove
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284 Node *sfpt = x->in(LoopNode::LoopBackControl);
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285 if( sfpt->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt)) {
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286 lazy_replace( sfpt, iftrue );
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287 loop->_tail = iftrue;
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288 }
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289
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290
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291 // If compare points to incr, we are ok. Otherwise the compare
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292 // can directly point to the phi; in this case adjust the compare so that
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293 // it points to the incr by adusting the limit.
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294 if( cmp->in(1) == phi || cmp->in(2) == phi )
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295 limit = gvn->transform(new (C, 3) AddINode(limit,stride));
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296
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297 // trip-count for +-tive stride should be: (limit - init_trip + stride - 1)/stride.
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298 // Final value for iterator should be: trip_count * stride + init_trip.
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299 const Type *limit_t = limit->bottom_type();
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300 const Type *init_t = init_trip->bottom_type();
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301 Node *one_p = gvn->intcon( 1);
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302 Node *one_m = gvn->intcon(-1);
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303
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304 Node *trip_count = NULL;
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305 Node *hook = new (C, 6) Node(6);
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306 switch( bt ) {
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307 case BoolTest::eq:
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308 return NULL; // Bail out, but this loop trips at most twice!
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309 case BoolTest::ne: // Ahh, the case we desire
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310 if( stride_con == 1 )
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311 trip_count = gvn->transform(new (C, 3) SubINode(limit,init_trip));
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312 else if( stride_con == -1 )
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313 trip_count = gvn->transform(new (C, 3) SubINode(init_trip,limit));
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314 else
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315 return NULL; // Odd stride; must prove we hit limit exactly
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316 set_subtree_ctrl( trip_count );
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317 //_loop.map(trip_count->_idx,loop(limit));
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318 break;
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319 case BoolTest::le: // Maybe convert to '<' case
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320 limit = gvn->transform(new (C, 3) AddINode(limit,one_p));
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321 set_subtree_ctrl( limit );
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322 hook->init_req(4, limit);
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323
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324 bt = BoolTest::lt;
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325 // Make the new limit be in the same loop nest as the old limit
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326 //_loop.map(limit->_idx,limit_loop);
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327 // Fall into next case
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328 case BoolTest::lt: { // Maybe convert to '!=' case
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329 if( stride_con < 0 ) return NULL; // Count down loop rolls through MAXINT
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330 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip));
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331 set_subtree_ctrl( range );
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332 hook->init_req(0, range);
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333
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334 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride));
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335 set_subtree_ctrl( bias );
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336 hook->init_req(1, bias);
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337
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338 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_m));
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339 set_subtree_ctrl( bias1 );
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340 hook->init_req(2, bias1);
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341
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342 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride));
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343 set_subtree_ctrl( trip_count );
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344 hook->init_req(3, trip_count);
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345 break;
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346 }
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347
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348 case BoolTest::ge: // Maybe convert to '>' case
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349 limit = gvn->transform(new (C, 3) AddINode(limit,one_m));
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350 set_subtree_ctrl( limit );
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351 hook->init_req(4 ,limit);
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352
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353 bt = BoolTest::gt;
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354 // Make the new limit be in the same loop nest as the old limit
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355 //_loop.map(limit->_idx,limit_loop);
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356 // Fall into next case
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357 case BoolTest::gt: { // Maybe convert to '!=' case
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358 if( stride_con > 0 ) return NULL; // count up loop rolls through MININT
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359 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip));
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360 set_subtree_ctrl( range );
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361 hook->init_req(0, range);
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362
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363 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride));
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364 set_subtree_ctrl( bias );
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365 hook->init_req(1, bias);
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366
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367 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_p));
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368 set_subtree_ctrl( bias1 );
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369 hook->init_req(2, bias1);
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370
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371 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride));
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372 set_subtree_ctrl( trip_count );
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373 hook->init_req(3, trip_count);
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374 break;
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375 }
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376 }
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377
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378 Node *span = gvn->transform(new (C, 3) MulINode(trip_count,stride));
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379 set_subtree_ctrl( span );
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380 hook->init_req(5, span);
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381
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382 limit = gvn->transform(new (C, 3) AddINode(span,init_trip));
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383 set_subtree_ctrl( limit );
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384
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385 // Build a canonical trip test.
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386 // Clone code, as old values may be in use.
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387 incr = incr->clone();
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388 incr->set_req(1,phi);
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389 incr->set_req(2,stride);
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390 incr = _igvn.register_new_node_with_optimizer(incr);
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391 set_early_ctrl( incr );
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392 _igvn.hash_delete(phi);
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393 phi->set_req_X( LoopNode::LoopBackControl, incr, &_igvn );
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394
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395 // If phi type is more restrictive than Int, raise to
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396 // Int to prevent (almost) infinite recursion in igvn
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397 // which can only handle integer types for constants or minint..maxint.
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398 if (!TypeInt::INT->higher_equal(phi->bottom_type())) {
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399 Node* nphi = PhiNode::make(phi->in(0), phi->in(LoopNode::EntryControl), TypeInt::INT);
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400 nphi->set_req(LoopNode::LoopBackControl, phi->in(LoopNode::LoopBackControl));
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401 nphi = _igvn.register_new_node_with_optimizer(nphi);
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402 set_ctrl(nphi, get_ctrl(phi));
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403 _igvn.subsume_node(phi, nphi);
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404 phi = nphi->as_Phi();
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405 }
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406 cmp = cmp->clone();
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407 cmp->set_req(1,incr);
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408 cmp->set_req(2,limit);
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409 cmp = _igvn.register_new_node_with_optimizer(cmp);
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410 set_ctrl(cmp, iff->in(0));
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411
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412 Node *tmp = test->clone();
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413 assert( tmp->is_Bool(), "" );
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414 test = (BoolNode*)tmp;
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415 (*(BoolTest*)&test->_test)._test = bt; //BoolTest::ne;
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416 test->set_req(1,cmp);
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417 _igvn.register_new_node_with_optimizer(test);
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418 set_ctrl(test, iff->in(0));
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419 // If the exit test is dead, STOP!
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420 if( test == NULL ) return NULL;
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421 _igvn.hash_delete(iff);
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422 iff->set_req_X( 1, test, &_igvn );
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423
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424 // Replace the old IfNode with a new LoopEndNode
|
|
425 Node *lex = _igvn.register_new_node_with_optimizer(new (C, 2) CountedLoopEndNode( iff->in(0), iff->in(1), cl_prob, iff->as_If()->_fcnt ));
|
|
426 IfNode *le = lex->as_If();
|
|
427 uint dd = dom_depth(iff);
|
|
428 set_idom(le, le->in(0), dd); // Update dominance for loop exit
|
|
429 set_loop(le, loop);
|
|
430
|
|
431 // Get the loop-exit control
|
|
432 Node *if_f = iff->as_If()->proj_out(!(iftrue_op == Op_IfTrue));
|
|
433
|
|
434 // Need to swap loop-exit and loop-back control?
|
|
435 if( iftrue_op == Op_IfFalse ) {
|
|
436 Node *ift2=_igvn.register_new_node_with_optimizer(new (C, 1) IfTrueNode (le));
|
|
437 Node *iff2=_igvn.register_new_node_with_optimizer(new (C, 1) IfFalseNode(le));
|
|
438
|
|
439 loop->_tail = back_control = ift2;
|
|
440 set_loop(ift2, loop);
|
|
441 set_loop(iff2, get_loop(if_f));
|
|
442
|
|
443 // Lazy update of 'get_ctrl' mechanism.
|
|
444 lazy_replace_proj( if_f , iff2 );
|
|
445 lazy_replace_proj( iftrue, ift2 );
|
|
446
|
|
447 // Swap names
|
|
448 if_f = iff2;
|
|
449 iftrue = ift2;
|
|
450 } else {
|
|
451 _igvn.hash_delete(if_f );
|
|
452 _igvn.hash_delete(iftrue);
|
|
453 if_f ->set_req_X( 0, le, &_igvn );
|
|
454 iftrue->set_req_X( 0, le, &_igvn );
|
|
455 }
|
|
456
|
|
457 set_idom(iftrue, le, dd+1);
|
|
458 set_idom(if_f, le, dd+1);
|
|
459
|
|
460 // Now setup a new CountedLoopNode to replace the existing LoopNode
|
|
461 CountedLoopNode *l = new (C, 3) CountedLoopNode(init_control, back_control);
|
|
462 // The following assert is approximately true, and defines the intention
|
|
463 // of can_be_counted_loop. It fails, however, because phase->type
|
|
464 // is not yet initialized for this loop and its parts.
|
|
465 //assert(l->can_be_counted_loop(this), "sanity");
|
|
466 _igvn.register_new_node_with_optimizer(l);
|
|
467 set_loop(l, loop);
|
|
468 loop->_head = l;
|
|
469 // Fix all data nodes placed at the old loop head.
|
|
470 // Uses the lazy-update mechanism of 'get_ctrl'.
|
|
471 lazy_replace( x, l );
|
|
472 set_idom(l, init_control, dom_depth(x));
|
|
473
|
|
474 // Check for immediately preceeding SafePoint and remove
|
|
475 Node *sfpt2 = le->in(0);
|
|
476 if( sfpt2->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt2))
|
|
477 lazy_replace( sfpt2, sfpt2->in(TypeFunc::Control));
|
|
478
|
|
479 // Free up intermediate goo
|
|
480 _igvn.remove_dead_node(hook);
|
|
481
|
|
482 C->print_method("After CountedLoop", 3);
|
|
483
|
|
484 // Return trip counter
|
|
485 return trip_count;
|
|
486 }
|
|
487
|
|
488
|
|
489 //------------------------------Ideal------------------------------------------
|
|
490 // Return a node which is more "ideal" than the current node.
|
|
491 // Attempt to convert into a counted-loop.
|
|
492 Node *LoopNode::Ideal(PhaseGVN *phase, bool can_reshape) {
|
|
493 if (!can_be_counted_loop(phase)) {
|
|
494 phase->C->set_major_progress();
|
|
495 }
|
|
496 return RegionNode::Ideal(phase, can_reshape);
|
|
497 }
|
|
498
|
|
499
|
|
500 //=============================================================================
|
|
501 //------------------------------Ideal------------------------------------------
|
|
502 // Return a node which is more "ideal" than the current node.
|
|
503 // Attempt to convert into a counted-loop.
|
|
504 Node *CountedLoopNode::Ideal(PhaseGVN *phase, bool can_reshape) {
|
|
505 return RegionNode::Ideal(phase, can_reshape);
|
|
506 }
|
|
507
|
|
508 //------------------------------dump_spec--------------------------------------
|
|
509 // Dump special per-node info
|
|
510 #ifndef PRODUCT
|
|
511 void CountedLoopNode::dump_spec(outputStream *st) const {
|
|
512 LoopNode::dump_spec(st);
|
|
513 if( stride_is_con() ) {
|
|
514 st->print("stride: %d ",stride_con());
|
|
515 } else {
|
|
516 st->print("stride: not constant ");
|
|
517 }
|
|
518 if( is_pre_loop () ) st->print("pre of N%d" , _main_idx );
|
|
519 if( is_main_loop() ) st->print("main of N%d", _idx );
|
|
520 if( is_post_loop() ) st->print("post of N%d", _main_idx );
|
|
521 }
|
|
522 #endif
|
|
523
|
|
524 //=============================================================================
|
|
525 int CountedLoopEndNode::stride_con() const {
|
|
526 return stride()->bottom_type()->is_int()->get_con();
|
|
527 }
|
|
528
|
|
529
|
|
530 //----------------------match_incr_with_optional_truncation--------------------
|
|
531 // Match increment with optional truncation:
|
|
532 // CHAR: (i+1)&0x7fff, BYTE: ((i+1)<<8)>>8, or SHORT: ((i+1)<<16)>>16
|
|
533 // Return NULL for failure. Success returns the increment node.
|
|
534 Node* CountedLoopNode::match_incr_with_optional_truncation(
|
|
535 Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type) {
|
|
536 // Quick cutouts:
|
|
537 if (expr == NULL || expr->req() != 3) return false;
|
|
538
|
|
539 Node *t1 = NULL;
|
|
540 Node *t2 = NULL;
|
|
541 const TypeInt* trunc_t = TypeInt::INT;
|
|
542 Node* n1 = expr;
|
|
543 int n1op = n1->Opcode();
|
|
544
|
|
545 // Try to strip (n1 & M) or (n1 << N >> N) from n1.
|
|
546 if (n1op == Op_AndI &&
|
|
547 n1->in(2)->is_Con() &&
|
|
548 n1->in(2)->bottom_type()->is_int()->get_con() == 0x7fff) {
|
|
549 // %%% This check should match any mask of 2**K-1.
|
|
550 t1 = n1;
|
|
551 n1 = t1->in(1);
|
|
552 n1op = n1->Opcode();
|
|
553 trunc_t = TypeInt::CHAR;
|
|
554 } else if (n1op == Op_RShiftI &&
|
|
555 n1->in(1) != NULL &&
|
|
556 n1->in(1)->Opcode() == Op_LShiftI &&
|
|
557 n1->in(2) == n1->in(1)->in(2) &&
|
|
558 n1->in(2)->is_Con()) {
|
|
559 jint shift = n1->in(2)->bottom_type()->is_int()->get_con();
|
|
560 // %%% This check should match any shift in [1..31].
|
|
561 if (shift == 16 || shift == 8) {
|
|
562 t1 = n1;
|
|
563 t2 = t1->in(1);
|
|
564 n1 = t2->in(1);
|
|
565 n1op = n1->Opcode();
|
|
566 if (shift == 16) {
|
|
567 trunc_t = TypeInt::SHORT;
|
|
568 } else if (shift == 8) {
|
|
569 trunc_t = TypeInt::BYTE;
|
|
570 }
|
|
571 }
|
|
572 }
|
|
573
|
|
574 // If (maybe after stripping) it is an AddI, we won:
|
|
575 if (n1op == Op_AddI) {
|
|
576 *trunc1 = t1;
|
|
577 *trunc2 = t2;
|
|
578 *trunc_type = trunc_t;
|
|
579 return n1;
|
|
580 }
|
|
581
|
|
582 // failed
|
|
583 return NULL;
|
|
584 }
|
|
585
|
|
586
|
|
587 //------------------------------filtered_type--------------------------------
|
|
588 // Return a type based on condition control flow
|
|
589 // A successful return will be a type that is restricted due
|
|
590 // to a series of dominating if-tests, such as:
|
|
591 // if (i < 10) {
|
|
592 // if (i > 0) {
|
|
593 // here: "i" type is [1..10)
|
|
594 // }
|
|
595 // }
|
|
596 // or a control flow merge
|
|
597 // if (i < 10) {
|
|
598 // do {
|
|
599 // phi( , ) -- at top of loop type is [min_int..10)
|
|
600 // i = ?
|
|
601 // } while ( i < 10)
|
|
602 //
|
|
603 const TypeInt* PhaseIdealLoop::filtered_type( Node *n, Node* n_ctrl) {
|
|
604 assert(n && n->bottom_type()->is_int(), "must be int");
|
|
605 const TypeInt* filtered_t = NULL;
|
|
606 if (!n->is_Phi()) {
|
|
607 assert(n_ctrl != NULL || n_ctrl == C->top(), "valid control");
|
|
608 filtered_t = filtered_type_from_dominators(n, n_ctrl);
|
|
609
|
|
610 } else {
|
|
611 Node* phi = n->as_Phi();
|
|
612 Node* region = phi->in(0);
|
|
613 assert(n_ctrl == NULL || n_ctrl == region, "ctrl parameter must be region");
|
|
614 if (region && region != C->top()) {
|
|
615 for (uint i = 1; i < phi->req(); i++) {
|
|
616 Node* val = phi->in(i);
|
|
617 Node* use_c = region->in(i);
|
|
618 const TypeInt* val_t = filtered_type_from_dominators(val, use_c);
|
|
619 if (val_t != NULL) {
|
|
620 if (filtered_t == NULL) {
|
|
621 filtered_t = val_t;
|
|
622 } else {
|
|
623 filtered_t = filtered_t->meet(val_t)->is_int();
|
|
624 }
|
|
625 }
|
|
626 }
|
|
627 }
|
|
628 }
|
|
629 const TypeInt* n_t = _igvn.type(n)->is_int();
|
|
630 if (filtered_t != NULL) {
|
|
631 n_t = n_t->join(filtered_t)->is_int();
|
|
632 }
|
|
633 return n_t;
|
|
634 }
|
|
635
|
|
636
|
|
637 //------------------------------filtered_type_from_dominators--------------------------------
|
|
638 // Return a possibly more restrictive type for val based on condition control flow of dominators
|
|
639 const TypeInt* PhaseIdealLoop::filtered_type_from_dominators( Node* val, Node *use_ctrl) {
|
|
640 if (val->is_Con()) {
|
|
641 return val->bottom_type()->is_int();
|
|
642 }
|
|
643 uint if_limit = 10; // Max number of dominating if's visited
|
|
644 const TypeInt* rtn_t = NULL;
|
|
645
|
|
646 if (use_ctrl && use_ctrl != C->top()) {
|
|
647 Node* val_ctrl = get_ctrl(val);
|
|
648 uint val_dom_depth = dom_depth(val_ctrl);
|
|
649 Node* pred = use_ctrl;
|
|
650 uint if_cnt = 0;
|
|
651 while (if_cnt < if_limit) {
|
|
652 if ((pred->Opcode() == Op_IfTrue || pred->Opcode() == Op_IfFalse)) {
|
|
653 if_cnt++;
|
|
654 const TypeInt* if_t = filtered_type_at_if(val, pred);
|
|
655 if (if_t != NULL) {
|
|
656 if (rtn_t == NULL) {
|
|
657 rtn_t = if_t;
|
|
658 } else {
|
|
659 rtn_t = rtn_t->join(if_t)->is_int();
|
|
660 }
|
|
661 }
|
|
662 }
|
|
663 pred = idom(pred);
|
|
664 if (pred == NULL || pred == C->top()) {
|
|
665 break;
|
|
666 }
|
|
667 // Stop if going beyond definition block of val
|
|
668 if (dom_depth(pred) < val_dom_depth) {
|
|
669 break;
|
|
670 }
|
|
671 }
|
|
672 }
|
|
673 return rtn_t;
|
|
674 }
|
|
675
|
|
676
|
|
677 //------------------------------filtered_type_at_if--------------------------------
|
|
678 // Return a possibly more restrictive type for val based on condition control flow for an if
|
|
679 const TypeInt* PhaseIdealLoop::filtered_type_at_if( Node* val, Node *if_proj) {
|
|
680 assert(if_proj &&
|
|
681 (if_proj->Opcode() == Op_IfTrue || if_proj->Opcode() == Op_IfFalse), "expecting an if projection");
|
|
682 if (if_proj->in(0) && if_proj->in(0)->is_If()) {
|
|
683 IfNode* iff = if_proj->in(0)->as_If();
|
|
684 if (iff->in(1) && iff->in(1)->is_Bool()) {
|
|
685 BoolNode* bol = iff->in(1)->as_Bool();
|
|
686 if (bol->in(1) && bol->in(1)->is_Cmp()) {
|
|
687 const CmpNode* cmp = bol->in(1)->as_Cmp();
|
|
688 if (cmp->in(1) == val) {
|
|
689 const TypeInt* cmp2_t = _igvn.type(cmp->in(2))->isa_int();
|
|
690 if (cmp2_t != NULL) {
|
|
691 jint lo = cmp2_t->_lo;
|
|
692 jint hi = cmp2_t->_hi;
|
|
693 BoolTest::mask msk = if_proj->Opcode() == Op_IfTrue ? bol->_test._test : bol->_test.negate();
|
|
694 switch (msk) {
|
|
695 case BoolTest::ne:
|
|
696 // Can't refine type
|
|
697 return NULL;
|
|
698 case BoolTest::eq:
|
|
699 return cmp2_t;
|
|
700 case BoolTest::lt:
|
|
701 lo = TypeInt::INT->_lo;
|
|
702 if (hi - 1 < hi) {
|
|
703 hi = hi - 1;
|
|
704 }
|
|
705 break;
|
|
706 case BoolTest::le:
|
|
707 lo = TypeInt::INT->_lo;
|
|
708 break;
|
|
709 case BoolTest::gt:
|
|
710 if (lo + 1 > lo) {
|
|
711 lo = lo + 1;
|
|
712 }
|
|
713 hi = TypeInt::INT->_hi;
|
|
714 break;
|
|
715 case BoolTest::ge:
|
|
716 // lo unchanged
|
|
717 hi = TypeInt::INT->_hi;
|
|
718 break;
|
|
719 }
|
|
720 const TypeInt* rtn_t = TypeInt::make(lo, hi, cmp2_t->_widen);
|
|
721 return rtn_t;
|
|
722 }
|
|
723 }
|
|
724 }
|
|
725 }
|
|
726 }
|
|
727 return NULL;
|
|
728 }
|
|
729
|
|
730 //------------------------------dump_spec--------------------------------------
|
|
731 // Dump special per-node info
|
|
732 #ifndef PRODUCT
|
|
733 void CountedLoopEndNode::dump_spec(outputStream *st) const {
|
|
734 if( in(TestValue)->is_Bool() ) {
|
|
735 BoolTest bt( test_trip()); // Added this for g++.
|
|
736
|
|
737 st->print("[");
|
|
738 bt.dump_on(st);
|
|
739 st->print("]");
|
|
740 }
|
|
741 st->print(" ");
|
|
742 IfNode::dump_spec(st);
|
|
743 }
|
|
744 #endif
|
|
745
|
|
746 //=============================================================================
|
|
747 //------------------------------is_member--------------------------------------
|
|
748 // Is 'l' a member of 'this'?
|
|
749 int IdealLoopTree::is_member( const IdealLoopTree *l ) const {
|
|
750 while( l->_nest > _nest ) l = l->_parent;
|
|
751 return l == this;
|
|
752 }
|
|
753
|
|
754 //------------------------------set_nest---------------------------------------
|
|
755 // Set loop tree nesting depth. Accumulate _has_call bits.
|
|
756 int IdealLoopTree::set_nest( uint depth ) {
|
|
757 _nest = depth;
|
|
758 int bits = _has_call;
|
|
759 if( _child ) bits |= _child->set_nest(depth+1);
|
|
760 if( bits ) _has_call = 1;
|
|
761 if( _next ) bits |= _next ->set_nest(depth );
|
|
762 return bits;
|
|
763 }
|
|
764
|
|
765 //------------------------------split_fall_in----------------------------------
|
|
766 // Split out multiple fall-in edges from the loop header. Move them to a
|
|
767 // private RegionNode before the loop. This becomes the loop landing pad.
|
|
768 void IdealLoopTree::split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ) {
|
|
769 PhaseIterGVN &igvn = phase->_igvn;
|
|
770 uint i;
|
|
771
|
|
772 // Make a new RegionNode to be the landing pad.
|
|
773 Node *landing_pad = new (phase->C, fall_in_cnt+1) RegionNode( fall_in_cnt+1 );
|
|
774 phase->set_loop(landing_pad,_parent);
|
|
775 // Gather all the fall-in control paths into the landing pad
|
|
776 uint icnt = fall_in_cnt;
|
|
777 uint oreq = _head->req();
|
|
778 for( i = oreq-1; i>0; i-- )
|
|
779 if( !phase->is_member( this, _head->in(i) ) )
|
|
780 landing_pad->set_req(icnt--,_head->in(i));
|
|
781
|
|
782 // Peel off PhiNode edges as well
|
|
783 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) {
|
|
784 Node *oj = _head->fast_out(j);
|
|
785 if( oj->is_Phi() ) {
|
|
786 PhiNode* old_phi = oj->as_Phi();
|
|
787 assert( old_phi->region() == _head, "" );
|
|
788 igvn.hash_delete(old_phi); // Yank from hash before hacking edges
|
|
789 Node *p = PhiNode::make_blank(landing_pad, old_phi);
|
|
790 uint icnt = fall_in_cnt;
|
|
791 for( i = oreq-1; i>0; i-- ) {
|
|
792 if( !phase->is_member( this, _head->in(i) ) ) {
|
|
793 p->init_req(icnt--, old_phi->in(i));
|
|
794 // Go ahead and clean out old edges from old phi
|
|
795 old_phi->del_req(i);
|
|
796 }
|
|
797 }
|
|
798 // Search for CSE's here, because ZKM.jar does a lot of
|
|
799 // loop hackery and we need to be a little incremental
|
|
800 // with the CSE to avoid O(N^2) node blow-up.
|
|
801 Node *p2 = igvn.hash_find_insert(p); // Look for a CSE
|
|
802 if( p2 ) { // Found CSE
|
|
803 p->destruct(); // Recover useless new node
|
|
804 p = p2; // Use old node
|
|
805 } else {
|
|
806 igvn.register_new_node_with_optimizer(p, old_phi);
|
|
807 }
|
|
808 // Make old Phi refer to new Phi.
|
|
809 old_phi->add_req(p);
|
|
810 // Check for the special case of making the old phi useless and
|
|
811 // disappear it. In JavaGrande I have a case where this useless
|
|
812 // Phi is the loop limit and prevents recognizing a CountedLoop
|
|
813 // which in turn prevents removing an empty loop.
|
|
814 Node *id_old_phi = old_phi->Identity( &igvn );
|
|
815 if( id_old_phi != old_phi ) { // Found a simple identity?
|
|
816 // Note that I cannot call 'subsume_node' here, because
|
|
817 // that will yank the edge from old_phi to the Region and
|
|
818 // I'm mid-iteration over the Region's uses.
|
|
819 for (DUIterator_Last imin, i = old_phi->last_outs(imin); i >= imin; ) {
|
|
820 Node* use = old_phi->last_out(i);
|
|
821 igvn.hash_delete(use);
|
|
822 igvn._worklist.push(use);
|
|
823 uint uses_found = 0;
|
|
824 for (uint j = 0; j < use->len(); j++) {
|
|
825 if (use->in(j) == old_phi) {
|
|
826 if (j < use->req()) use->set_req (j, id_old_phi);
|
|
827 else use->set_prec(j, id_old_phi);
|
|
828 uses_found++;
|
|
829 }
|
|
830 }
|
|
831 i -= uses_found; // we deleted 1 or more copies of this edge
|
|
832 }
|
|
833 }
|
|
834 igvn._worklist.push(old_phi);
|
|
835 }
|
|
836 }
|
|
837 // Finally clean out the fall-in edges from the RegionNode
|
|
838 for( i = oreq-1; i>0; i-- ) {
|
|
839 if( !phase->is_member( this, _head->in(i) ) ) {
|
|
840 _head->del_req(i);
|
|
841 }
|
|
842 }
|
|
843 // Transform landing pad
|
|
844 igvn.register_new_node_with_optimizer(landing_pad, _head);
|
|
845 // Insert landing pad into the header
|
|
846 _head->add_req(landing_pad);
|
|
847 }
|
|
848
|
|
849 //------------------------------split_outer_loop-------------------------------
|
|
850 // Split out the outermost loop from this shared header.
|
|
851 void IdealLoopTree::split_outer_loop( PhaseIdealLoop *phase ) {
|
|
852 PhaseIterGVN &igvn = phase->_igvn;
|
|
853
|
|
854 // Find index of outermost loop; it should also be my tail.
|
|
855 uint outer_idx = 1;
|
|
856 while( _head->in(outer_idx) != _tail ) outer_idx++;
|
|
857
|
|
858 // Make a LoopNode for the outermost loop.
|
|
859 Node *ctl = _head->in(LoopNode::EntryControl);
|
|
860 Node *outer = new (phase->C, 3) LoopNode( ctl, _head->in(outer_idx) );
|
|
861 outer = igvn.register_new_node_with_optimizer(outer, _head);
|
|
862 phase->set_created_loop_node();
|
|
863 // Outermost loop falls into '_head' loop
|
|
864 _head->set_req(LoopNode::EntryControl, outer);
|
|
865 _head->del_req(outer_idx);
|
|
866 // Split all the Phis up between '_head' loop and 'outer' loop.
|
|
867 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) {
|
|
868 Node *out = _head->fast_out(j);
|
|
869 if( out->is_Phi() ) {
|
|
870 PhiNode *old_phi = out->as_Phi();
|
|
871 assert( old_phi->region() == _head, "" );
|
|
872 Node *phi = PhiNode::make_blank(outer, old_phi);
|
|
873 phi->init_req(LoopNode::EntryControl, old_phi->in(LoopNode::EntryControl));
|
|
874 phi->init_req(LoopNode::LoopBackControl, old_phi->in(outer_idx));
|
|
875 phi = igvn.register_new_node_with_optimizer(phi, old_phi);
|
|
876 // Make old Phi point to new Phi on the fall-in path
|
|
877 igvn.hash_delete(old_phi);
|
|
878 old_phi->set_req(LoopNode::EntryControl, phi);
|
|
879 old_phi->del_req(outer_idx);
|
|
880 igvn._worklist.push(old_phi);
|
|
881 }
|
|
882 }
|
|
883
|
|
884 // Use the new loop head instead of the old shared one
|
|
885 _head = outer;
|
|
886 phase->set_loop(_head, this);
|
|
887 }
|
|
888
|
|
889 //------------------------------fix_parent-------------------------------------
|
|
890 static void fix_parent( IdealLoopTree *loop, IdealLoopTree *parent ) {
|
|
891 loop->_parent = parent;
|
|
892 if( loop->_child ) fix_parent( loop->_child, loop );
|
|
893 if( loop->_next ) fix_parent( loop->_next , parent );
|
|
894 }
|
|
895
|
|
896 //------------------------------estimate_path_freq-----------------------------
|
|
897 static float estimate_path_freq( Node *n ) {
|
|
898 // Try to extract some path frequency info
|
|
899 IfNode *iff;
|
|
900 for( int i = 0; i < 50; i++ ) { // Skip through a bunch of uncommon tests
|
|
901 uint nop = n->Opcode();
|
|
902 if( nop == Op_SafePoint ) { // Skip any safepoint
|
|
903 n = n->in(0);
|
|
904 continue;
|
|
905 }
|
|
906 if( nop == Op_CatchProj ) { // Get count from a prior call
|
|
907 // Assume call does not always throw exceptions: means the call-site
|
|
908 // count is also the frequency of the fall-through path.
|
|
909 assert( n->is_CatchProj(), "" );
|
|
910 if( ((CatchProjNode*)n)->_con != CatchProjNode::fall_through_index )
|
|
911 return 0.0f; // Assume call exception path is rare
|
|
912 Node *call = n->in(0)->in(0)->in(0);
|
|
913 assert( call->is_Call(), "expect a call here" );
|
|
914 const JVMState *jvms = ((CallNode*)call)->jvms();
|
|
915 ciMethodData* methodData = jvms->method()->method_data();
|
|
916 if (!methodData->is_mature()) return 0.0f; // No call-site data
|
|
917 ciProfileData* data = methodData->bci_to_data(jvms->bci());
|
|
918 if ((data == NULL) || !data->is_CounterData()) {
|
|
919 // no call profile available, try call's control input
|
|
920 n = n->in(0);
|
|
921 continue;
|
|
922 }
|
|
923 return data->as_CounterData()->count()/FreqCountInvocations;
|
|
924 }
|
|
925 // See if there's a gating IF test
|
|
926 Node *n_c = n->in(0);
|
|
927 if( !n_c->is_If() ) break; // No estimate available
|
|
928 iff = n_c->as_If();
|
|
929 if( iff->_fcnt != COUNT_UNKNOWN ) // Have a valid count?
|
|
930 // Compute how much count comes on this path
|
|
931 return ((nop == Op_IfTrue) ? iff->_prob : 1.0f - iff->_prob) * iff->_fcnt;
|
|
932 // Have no count info. Skip dull uncommon-trap like branches.
|
|
933 if( (nop == Op_IfTrue && iff->_prob < PROB_LIKELY_MAG(5)) ||
|
|
934 (nop == Op_IfFalse && iff->_prob > PROB_UNLIKELY_MAG(5)) )
|
|
935 break;
|
|
936 // Skip through never-taken branch; look for a real loop exit.
|
|
937 n = iff->in(0);
|
|
938 }
|
|
939 return 0.0f; // No estimate available
|
|
940 }
|
|
941
|
|
942 //------------------------------merge_many_backedges---------------------------
|
|
943 // Merge all the backedges from the shared header into a private Region.
|
|
944 // Feed that region as the one backedge to this loop.
|
|
945 void IdealLoopTree::merge_many_backedges( PhaseIdealLoop *phase ) {
|
|
946 uint i;
|
|
947
|
|
948 // Scan for the top 2 hottest backedges
|
|
949 float hotcnt = 0.0f;
|
|
950 float warmcnt = 0.0f;
|
|
951 uint hot_idx = 0;
|
|
952 // Loop starts at 2 because slot 1 is the fall-in path
|
|
953 for( i = 2; i < _head->req(); i++ ) {
|
|
954 float cnt = estimate_path_freq(_head->in(i));
|
|
955 if( cnt > hotcnt ) { // Grab hottest path
|
|
956 warmcnt = hotcnt;
|
|
957 hotcnt = cnt;
|
|
958 hot_idx = i;
|
|
959 } else if( cnt > warmcnt ) { // And 2nd hottest path
|
|
960 warmcnt = cnt;
|
|
961 }
|
|
962 }
|
|
963
|
|
964 // See if the hottest backedge is worthy of being an inner loop
|
|
965 // by being much hotter than the next hottest backedge.
|
|
966 if( hotcnt <= 0.0001 ||
|
|
967 hotcnt < 2.0*warmcnt ) hot_idx = 0;// No hot backedge
|
|
968
|
|
969 // Peel out the backedges into a private merge point; peel
|
|
970 // them all except optionally hot_idx.
|
|
971 PhaseIterGVN &igvn = phase->_igvn;
|
|
972
|
|
973 Node *hot_tail = NULL;
|
|
974 // Make a Region for the merge point
|
|
975 Node *r = new (phase->C, 1) RegionNode(1);
|
|
976 for( i = 2; i < _head->req(); i++ ) {
|
|
977 if( i != hot_idx )
|
|
978 r->add_req( _head->in(i) );
|
|
979 else hot_tail = _head->in(i);
|
|
980 }
|
|
981 igvn.register_new_node_with_optimizer(r, _head);
|
|
982 // Plug region into end of loop _head, followed by hot_tail
|
|
983 while( _head->req() > 3 ) _head->del_req( _head->req()-1 );
|
|
984 _head->set_req(2, r);
|
|
985 if( hot_idx ) _head->add_req(hot_tail);
|
|
986
|
|
987 // Split all the Phis up between '_head' loop and the Region 'r'
|
|
988 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) {
|
|
989 Node *out = _head->fast_out(j);
|
|
990 if( out->is_Phi() ) {
|
|
991 PhiNode* n = out->as_Phi();
|
|
992 igvn.hash_delete(n); // Delete from hash before hacking edges
|
|
993 Node *hot_phi = NULL;
|
|
994 Node *phi = new (phase->C, r->req()) PhiNode(r, n->type(), n->adr_type());
|
|
995 // Check all inputs for the ones to peel out
|
|
996 uint j = 1;
|
|
997 for( uint i = 2; i < n->req(); i++ ) {
|
|
998 if( i != hot_idx )
|
|
999 phi->set_req( j++, n->in(i) );
|
|
1000 else hot_phi = n->in(i);
|
|
1001 }
|
|
1002 // Register the phi but do not transform until whole place transforms
|
|
1003 igvn.register_new_node_with_optimizer(phi, n);
|
|
1004 // Add the merge phi to the old Phi
|
|
1005 while( n->req() > 3 ) n->del_req( n->req()-1 );
|
|
1006 n->set_req(2, phi);
|
|
1007 if( hot_idx ) n->add_req(hot_phi);
|
|
1008 }
|
|
1009 }
|
|
1010
|
|
1011
|
|
1012 // Insert a new IdealLoopTree inserted below me. Turn it into a clone
|
|
1013 // of self loop tree. Turn self into a loop headed by _head and with
|
|
1014 // tail being the new merge point.
|
|
1015 IdealLoopTree *ilt = new IdealLoopTree( phase, _head, _tail );
|
|
1016 phase->set_loop(_tail,ilt); // Adjust tail
|
|
1017 _tail = r; // Self's tail is new merge point
|
|
1018 phase->set_loop(r,this);
|
|
1019 ilt->_child = _child; // New guy has my children
|
|
1020 _child = ilt; // Self has new guy as only child
|
|
1021 ilt->_parent = this; // new guy has self for parent
|
|
1022 ilt->_nest = _nest; // Same nesting depth (for now)
|
|
1023
|
|
1024 // Starting with 'ilt', look for child loop trees using the same shared
|
|
1025 // header. Flatten these out; they will no longer be loops in the end.
|
|
1026 IdealLoopTree **pilt = &_child;
|
|
1027 while( ilt ) {
|
|
1028 if( ilt->_head == _head ) {
|
|
1029 uint i;
|
|
1030 for( i = 2; i < _head->req(); i++ )
|
|
1031 if( _head->in(i) == ilt->_tail )
|
|
1032 break; // Still a loop
|
|
1033 if( i == _head->req() ) { // No longer a loop
|
|
1034 // Flatten ilt. Hang ilt's "_next" list from the end of
|
|
1035 // ilt's '_child' list. Move the ilt's _child up to replace ilt.
|
|
1036 IdealLoopTree **cp = &ilt->_child;
|
|
1037 while( *cp ) cp = &(*cp)->_next; // Find end of child list
|
|
1038 *cp = ilt->_next; // Hang next list at end of child list
|
|
1039 *pilt = ilt->_child; // Move child up to replace ilt
|
|
1040 ilt->_head = NULL; // Flag as a loop UNIONED into parent
|
|
1041 ilt = ilt->_child; // Repeat using new ilt
|
|
1042 continue; // do not advance over ilt->_child
|
|
1043 }
|
|
1044 assert( ilt->_tail == hot_tail, "expected to only find the hot inner loop here" );
|
|
1045 phase->set_loop(_head,ilt);
|
|
1046 }
|
|
1047 pilt = &ilt->_child; // Advance to next
|
|
1048 ilt = *pilt;
|
|
1049 }
|
|
1050
|
|
1051 if( _child ) fix_parent( _child, this );
|
|
1052 }
|
|
1053
|
|
1054 //------------------------------beautify_loops---------------------------------
|
|
1055 // Split shared headers and insert loop landing pads.
|
|
1056 // Insert a LoopNode to replace the RegionNode.
|
|
1057 // Return TRUE if loop tree is structurally changed.
|
|
1058 bool IdealLoopTree::beautify_loops( PhaseIdealLoop *phase ) {
|
|
1059 bool result = false;
|
|
1060 // Cache parts in locals for easy
|
|
1061 PhaseIterGVN &igvn = phase->_igvn;
|
|
1062
|
|
1063 phase->C->print_method("Before beautify loops", 3);
|
|
1064
|
|
1065 igvn.hash_delete(_head); // Yank from hash before hacking edges
|
|
1066
|
|
1067 // Check for multiple fall-in paths. Peel off a landing pad if need be.
|
|
1068 int fall_in_cnt = 0;
|
|
1069 for( uint i = 1; i < _head->req(); i++ )
|
|
1070 if( !phase->is_member( this, _head->in(i) ) )
|
|
1071 fall_in_cnt++;
|
|
1072 assert( fall_in_cnt, "at least 1 fall-in path" );
|
|
1073 if( fall_in_cnt > 1 ) // Need a loop landing pad to merge fall-ins
|
|
1074 split_fall_in( phase, fall_in_cnt );
|
|
1075
|
|
1076 // Swap inputs to the _head and all Phis to move the fall-in edge to
|
|
1077 // the left.
|
|
1078 fall_in_cnt = 1;
|
|
1079 while( phase->is_member( this, _head->in(fall_in_cnt) ) )
|
|
1080 fall_in_cnt++;
|
|
1081 if( fall_in_cnt > 1 ) {
|
|
1082 // Since I am just swapping inputs I do not need to update def-use info
|
|
1083 Node *tmp = _head->in(1);
|
|
1084 _head->set_req( 1, _head->in(fall_in_cnt) );
|
|
1085 _head->set_req( fall_in_cnt, tmp );
|
|
1086 // Swap also all Phis
|
|
1087 for (DUIterator_Fast imax, i = _head->fast_outs(imax); i < imax; i++) {
|
|
1088 Node* phi = _head->fast_out(i);
|
|
1089 if( phi->is_Phi() ) {
|
|
1090 igvn.hash_delete(phi); // Yank from hash before hacking edges
|
|
1091 tmp = phi->in(1);
|
|
1092 phi->set_req( 1, phi->in(fall_in_cnt) );
|
|
1093 phi->set_req( fall_in_cnt, tmp );
|
|
1094 }
|
|
1095 }
|
|
1096 }
|
|
1097 assert( !phase->is_member( this, _head->in(1) ), "left edge is fall-in" );
|
|
1098 assert( phase->is_member( this, _head->in(2) ), "right edge is loop" );
|
|
1099
|
|
1100 // If I am a shared header (multiple backedges), peel off the many
|
|
1101 // backedges into a private merge point and use the merge point as
|
|
1102 // the one true backedge.
|
|
1103 if( _head->req() > 3 ) {
|
|
1104 // Merge the many backedges into a single backedge.
|
|
1105 merge_many_backedges( phase );
|
|
1106 result = true;
|
|
1107 }
|
|
1108
|
|
1109 // If I am a shared header (multiple backedges), peel off myself loop.
|
|
1110 // I better be the outermost loop.
|
|
1111 if( _head->req() > 3 ) {
|
|
1112 split_outer_loop( phase );
|
|
1113 result = true;
|
|
1114
|
|
1115 } else if( !_head->is_Loop() && !_irreducible ) {
|
|
1116 // Make a new LoopNode to replace the old loop head
|
|
1117 Node *l = new (phase->C, 3) LoopNode( _head->in(1), _head->in(2) );
|
|
1118 l = igvn.register_new_node_with_optimizer(l, _head);
|
|
1119 phase->set_created_loop_node();
|
|
1120 // Go ahead and replace _head
|
|
1121 phase->_igvn.subsume_node( _head, l );
|
|
1122 _head = l;
|
|
1123 phase->set_loop(_head, this);
|
|
1124 for (DUIterator_Fast imax, i = l->fast_outs(imax); i < imax; i++)
|
|
1125 phase->_igvn.add_users_to_worklist(l->fast_out(i));
|
|
1126 }
|
|
1127
|
|
1128 phase->C->print_method("After beautify loops", 3);
|
|
1129
|
|
1130 // Now recursively beautify nested loops
|
|
1131 if( _child ) result |= _child->beautify_loops( phase );
|
|
1132 if( _next ) result |= _next ->beautify_loops( phase );
|
|
1133 return result;
|
|
1134 }
|
|
1135
|
|
1136 //------------------------------allpaths_check_safepts----------------------------
|
|
1137 // Allpaths backwards scan from loop tail, terminating each path at first safepoint
|
|
1138 // encountered. Helper for check_safepts.
|
|
1139 void IdealLoopTree::allpaths_check_safepts(VectorSet &visited, Node_List &stack) {
|
|
1140 assert(stack.size() == 0, "empty stack");
|
|
1141 stack.push(_tail);
|
|
1142 visited.Clear();
|
|
1143 visited.set(_tail->_idx);
|
|
1144 while (stack.size() > 0) {
|
|
1145 Node* n = stack.pop();
|
|
1146 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) {
|
|
1147 // Terminate this path
|
|
1148 } else if (n->Opcode() == Op_SafePoint) {
|
|
1149 if (_phase->get_loop(n) != this) {
|
|
1150 if (_required_safept == NULL) _required_safept = new Node_List();
|
|
1151 _required_safept->push(n); // save the one closest to the tail
|
|
1152 }
|
|
1153 // Terminate this path
|
|
1154 } else {
|
|
1155 uint start = n->is_Region() ? 1 : 0;
|
|
1156 uint end = n->is_Region() && !n->is_Loop() ? n->req() : start + 1;
|
|
1157 for (uint i = start; i < end; i++) {
|
|
1158 Node* in = n->in(i);
|
|
1159 assert(in->is_CFG(), "must be");
|
|
1160 if (!visited.test_set(in->_idx) && is_member(_phase->get_loop(in))) {
|
|
1161 stack.push(in);
|
|
1162 }
|
|
1163 }
|
|
1164 }
|
|
1165 }
|
|
1166 }
|
|
1167
|
|
1168 //------------------------------check_safepts----------------------------
|
|
1169 // Given dominators, try to find loops with calls that must always be
|
|
1170 // executed (call dominates loop tail). These loops do not need non-call
|
|
1171 // safepoints (ncsfpt).
|
|
1172 //
|
|
1173 // A complication is that a safepoint in a inner loop may be needed
|
|
1174 // by an outer loop. In the following, the inner loop sees it has a
|
|
1175 // call (block 3) on every path from the head (block 2) to the
|
|
1176 // backedge (arc 3->2). So it deletes the ncsfpt (non-call safepoint)
|
|
1177 // in block 2, _but_ this leaves the outer loop without a safepoint.
|
|
1178 //
|
|
1179 // entry 0
|
|
1180 // |
|
|
1181 // v
|
|
1182 // outer 1,2 +->1
|
|
1183 // | |
|
|
1184 // | v
|
|
1185 // | 2<---+ ncsfpt in 2
|
|
1186 // |_/|\ |
|
|
1187 // | v |
|
|
1188 // inner 2,3 / 3 | call in 3
|
|
1189 // / | |
|
|
1190 // v +--+
|
|
1191 // exit 4
|
|
1192 //
|
|
1193 //
|
|
1194 // This method creates a list (_required_safept) of ncsfpt nodes that must
|
|
1195 // be protected is created for each loop. When a ncsfpt maybe deleted, it
|
|
1196 // is first looked for in the lists for the outer loops of the current loop.
|
|
1197 //
|
|
1198 // The insights into the problem:
|
|
1199 // A) counted loops are okay
|
|
1200 // B) innermost loops are okay (only an inner loop can delete
|
|
1201 // a ncsfpt needed by an outer loop)
|
|
1202 // C) a loop is immune from an inner loop deleting a safepoint
|
|
1203 // if the loop has a call on the idom-path
|
|
1204 // D) a loop is also immune if it has a ncsfpt (non-call safepoint) on the
|
|
1205 // idom-path that is not in a nested loop
|
|
1206 // E) otherwise, an ncsfpt on the idom-path that is nested in an inner
|
|
1207 // loop needs to be prevented from deletion by an inner loop
|
|
1208 //
|
|
1209 // There are two analyses:
|
|
1210 // 1) The first, and cheaper one, scans the loop body from
|
|
1211 // tail to head following the idom (immediate dominator)
|
|
1212 // chain, looking for the cases (C,D,E) above.
|
|
1213 // Since inner loops are scanned before outer loops, there is summary
|
|
1214 // information about inner loops. Inner loops can be skipped over
|
|
1215 // when the tail of an inner loop is encountered.
|
|
1216 //
|
|
1217 // 2) The second, invoked if the first fails to find a call or ncsfpt on
|
|
1218 // the idom path (which is rare), scans all predecessor control paths
|
|
1219 // from the tail to the head, terminating a path when a call or sfpt
|
|
1220 // is encountered, to find the ncsfpt's that are closest to the tail.
|
|
1221 //
|
|
1222 void IdealLoopTree::check_safepts(VectorSet &visited, Node_List &stack) {
|
|
1223 // Bottom up traversal
|
|
1224 IdealLoopTree* ch = _child;
|
|
1225 while (ch != NULL) {
|
|
1226 ch->check_safepts(visited, stack);
|
|
1227 ch = ch->_next;
|
|
1228 }
|
|
1229
|
|
1230 if (!_head->is_CountedLoop() && !_has_sfpt && _parent != NULL && !_irreducible) {
|
|
1231 bool has_call = false; // call on dom-path
|
|
1232 bool has_local_ncsfpt = false; // ncsfpt on dom-path at this loop depth
|
|
1233 Node* nonlocal_ncsfpt = NULL; // ncsfpt on dom-path at a deeper depth
|
|
1234 // Scan the dom-path nodes from tail to head
|
|
1235 for (Node* n = tail(); n != _head; n = _phase->idom(n)) {
|
|
1236 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) {
|
|
1237 has_call = true;
|
|
1238 _has_sfpt = 1; // Then no need for a safept!
|
|
1239 break;
|
|
1240 } else if (n->Opcode() == Op_SafePoint) {
|
|
1241 if (_phase->get_loop(n) == this) {
|
|
1242 has_local_ncsfpt = true;
|
|
1243 break;
|
|
1244 }
|
|
1245 if (nonlocal_ncsfpt == NULL) {
|
|
1246 nonlocal_ncsfpt = n; // save the one closest to the tail
|
|
1247 }
|
|
1248 } else {
|
|
1249 IdealLoopTree* nlpt = _phase->get_loop(n);
|
|
1250 if (this != nlpt) {
|
|
1251 // If at an inner loop tail, see if the inner loop has already
|
|
1252 // recorded seeing a call on the dom-path (and stop.) If not,
|
|
1253 // jump to the head of the inner loop.
|
|
1254 assert(is_member(nlpt), "nested loop");
|
|
1255 Node* tail = nlpt->_tail;
|
|
1256 if (tail->in(0)->is_If()) tail = tail->in(0);
|
|
1257 if (n == tail) {
|
|
1258 // If inner loop has call on dom-path, so does outer loop
|
|
1259 if (nlpt->_has_sfpt) {
|
|
1260 has_call = true;
|
|
1261 _has_sfpt = 1;
|
|
1262 break;
|
|
1263 }
|
|
1264 // Skip to head of inner loop
|
|
1265 assert(_phase->is_dominator(_head, nlpt->_head), "inner head dominated by outer head");
|
|
1266 n = nlpt->_head;
|
|
1267 }
|
|
1268 }
|
|
1269 }
|
|
1270 }
|
|
1271 // Record safept's that this loop needs preserved when an
|
|
1272 // inner loop attempts to delete it's safepoints.
|
|
1273 if (_child != NULL && !has_call && !has_local_ncsfpt) {
|
|
1274 if (nonlocal_ncsfpt != NULL) {
|
|
1275 if (_required_safept == NULL) _required_safept = new Node_List();
|
|
1276 _required_safept->push(nonlocal_ncsfpt);
|
|
1277 } else {
|
|
1278 // Failed to find a suitable safept on the dom-path. Now use
|
|
1279 // an all paths walk from tail to head, looking for safepoints to preserve.
|
|
1280 allpaths_check_safepts(visited, stack);
|
|
1281 }
|
|
1282 }
|
|
1283 }
|
|
1284 }
|
|
1285
|
|
1286 //---------------------------is_deleteable_safept----------------------------
|
|
1287 // Is safept not required by an outer loop?
|
|
1288 bool PhaseIdealLoop::is_deleteable_safept(Node* sfpt) {
|
|
1289 assert(sfpt->Opcode() == Op_SafePoint, "");
|
|
1290 IdealLoopTree* lp = get_loop(sfpt)->_parent;
|
|
1291 while (lp != NULL) {
|
|
1292 Node_List* sfpts = lp->_required_safept;
|
|
1293 if (sfpts != NULL) {
|
|
1294 for (uint i = 0; i < sfpts->size(); i++) {
|
|
1295 if (sfpt == sfpts->at(i))
|
|
1296 return false;
|
|
1297 }
|
|
1298 }
|
|
1299 lp = lp->_parent;
|
|
1300 }
|
|
1301 return true;
|
|
1302 }
|
|
1303
|
|
1304 //------------------------------counted_loop-----------------------------------
|
|
1305 // Convert to counted loops where possible
|
|
1306 void IdealLoopTree::counted_loop( PhaseIdealLoop *phase ) {
|
|
1307
|
|
1308 // For grins, set the inner-loop flag here
|
|
1309 if( !_child ) {
|
|
1310 if( _head->is_Loop() ) _head->as_Loop()->set_inner_loop();
|
|
1311 }
|
|
1312
|
|
1313 if( _head->is_CountedLoop() ||
|
|
1314 phase->is_counted_loop( _head, this ) ) {
|
|
1315 _has_sfpt = 1; // Indicate we do not need a safepoint here
|
|
1316
|
|
1317 // Look for a safepoint to remove
|
|
1318 for (Node* n = tail(); n != _head; n = phase->idom(n))
|
|
1319 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this &&
|
|
1320 phase->is_deleteable_safept(n))
|
|
1321 phase->lazy_replace(n,n->in(TypeFunc::Control));
|
|
1322
|
|
1323 CountedLoopNode *cl = _head->as_CountedLoop();
|
|
1324 Node *incr = cl->incr();
|
|
1325 if( !incr ) return; // Dead loop?
|
|
1326 Node *init = cl->init_trip();
|
|
1327 Node *phi = cl->phi();
|
|
1328 // protect against stride not being a constant
|
|
1329 if( !cl->stride_is_con() ) return;
|
|
1330 int stride_con = cl->stride_con();
|
|
1331
|
|
1332 // Look for induction variables
|
|
1333
|
|
1334 // Visit all children, looking for Phis
|
|
1335 for (DUIterator i = cl->outs(); cl->has_out(i); i++) {
|
|
1336 Node *out = cl->out(i);
|
|
1337 if (!out->is_Phi()) continue; // Looking for phis
|
|
1338 PhiNode* phi2 = out->as_Phi();
|
|
1339 Node *incr2 = phi2->in( LoopNode::LoopBackControl );
|
|
1340 // Look for induction variables of the form: X += constant
|
|
1341 if( phi2->region() != _head ||
|
|
1342 incr2->req() != 3 ||
|
|
1343 incr2->in(1) != phi2 ||
|
|
1344 incr2 == incr ||
|
|
1345 incr2->Opcode() != Op_AddI ||
|
|
1346 !incr2->in(2)->is_Con() )
|
|
1347 continue;
|
|
1348
|
|
1349 // Check for parallel induction variable (parallel to trip counter)
|
|
1350 // via an affine function. In particular, count-down loops with
|
|
1351 // count-up array indices are common. We only RCE references off
|
|
1352 // the trip-counter, so we need to convert all these to trip-counter
|
|
1353 // expressions.
|
|
1354 Node *init2 = phi2->in( LoopNode::EntryControl );
|
|
1355 int stride_con2 = incr2->in(2)->get_int();
|
|
1356
|
|
1357 // The general case here gets a little tricky. We want to find the
|
|
1358 // GCD of all possible parallel IV's and make a new IV using this
|
|
1359 // GCD for the loop. Then all possible IVs are simple multiples of
|
|
1360 // the GCD. In practice, this will cover very few extra loops.
|
|
1361 // Instead we require 'stride_con2' to be a multiple of 'stride_con',
|
|
1362 // where +/-1 is the common case, but other integer multiples are
|
|
1363 // also easy to handle.
|
|
1364 int ratio_con = stride_con2/stride_con;
|
|
1365
|
|
1366 if( ratio_con * stride_con == stride_con2 ) { // Check for exact
|
|
1367 // Convert to using the trip counter. The parallel induction
|
|
1368 // variable differs from the trip counter by a loop-invariant
|
|
1369 // amount, the difference between their respective initial values.
|
|
1370 // It is scaled by the 'ratio_con'.
|
|
1371 Compile* C = phase->C;
|
|
1372 Node* ratio = phase->_igvn.intcon(ratio_con);
|
|
1373 phase->set_ctrl(ratio, C->root());
|
|
1374 Node* ratio_init = new (C, 3) MulINode(init, ratio);
|
|
1375 phase->_igvn.register_new_node_with_optimizer(ratio_init, init);
|
|
1376 phase->set_early_ctrl(ratio_init);
|
|
1377 Node* diff = new (C, 3) SubINode(init2, ratio_init);
|
|
1378 phase->_igvn.register_new_node_with_optimizer(diff, init2);
|
|
1379 phase->set_early_ctrl(diff);
|
|
1380 Node* ratio_idx = new (C, 3) MulINode(phi, ratio);
|
|
1381 phase->_igvn.register_new_node_with_optimizer(ratio_idx, phi);
|
|
1382 phase->set_ctrl(ratio_idx, cl);
|
|
1383 Node* add = new (C, 3) AddINode(ratio_idx, diff);
|
|
1384 phase->_igvn.register_new_node_with_optimizer(add);
|
|
1385 phase->set_ctrl(add, cl);
|
|
1386 phase->_igvn.hash_delete( phi2 );
|
|
1387 phase->_igvn.subsume_node( phi2, add );
|
|
1388 // Sometimes an induction variable is unused
|
|
1389 if (add->outcnt() == 0) {
|
|
1390 phase->_igvn.remove_dead_node(add);
|
|
1391 }
|
|
1392 --i; // deleted this phi; rescan starting with next position
|
|
1393 continue;
|
|
1394 }
|
|
1395 }
|
|
1396 } else if (_parent != NULL && !_irreducible) {
|
|
1397 // Not a counted loop.
|
|
1398 // Look for a safepoint on the idom-path to remove, preserving the first one
|
|
1399 bool found = false;
|
|
1400 Node* n = tail();
|
|
1401 for (; n != _head && !found; n = phase->idom(n)) {
|
|
1402 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this)
|
|
1403 found = true; // Found one
|
|
1404 }
|
|
1405 // Skip past it and delete the others
|
|
1406 for (; n != _head; n = phase->idom(n)) {
|
|
1407 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this &&
|
|
1408 phase->is_deleteable_safept(n))
|
|
1409 phase->lazy_replace(n,n->in(TypeFunc::Control));
|
|
1410 }
|
|
1411 }
|
|
1412
|
|
1413 // Recursively
|
|
1414 if( _child ) _child->counted_loop( phase );
|
|
1415 if( _next ) _next ->counted_loop( phase );
|
|
1416 }
|
|
1417
|
|
1418 #ifndef PRODUCT
|
|
1419 //------------------------------dump_head--------------------------------------
|
|
1420 // Dump 1 liner for loop header info
|
|
1421 void IdealLoopTree::dump_head( ) const {
|
|
1422 for( uint i=0; i<_nest; i++ )
|
|
1423 tty->print(" ");
|
|
1424 tty->print("Loop: N%d/N%d ",_head->_idx,_tail->_idx);
|
|
1425 if( _irreducible ) tty->print(" IRREDUCIBLE");
|
|
1426 if( _head->is_CountedLoop() ) {
|
|
1427 CountedLoopNode *cl = _head->as_CountedLoop();
|
|
1428 tty->print(" counted");
|
|
1429 if( cl->is_pre_loop () ) tty->print(" pre" );
|
|
1430 if( cl->is_main_loop() ) tty->print(" main");
|
|
1431 if( cl->is_post_loop() ) tty->print(" post");
|
|
1432 }
|
|
1433 tty->cr();
|
|
1434 }
|
|
1435
|
|
1436 //------------------------------dump-------------------------------------------
|
|
1437 // Dump loops by loop tree
|
|
1438 void IdealLoopTree::dump( ) const {
|
|
1439 dump_head();
|
|
1440 if( _child ) _child->dump();
|
|
1441 if( _next ) _next ->dump();
|
|
1442 }
|
|
1443
|
|
1444 #endif
|
|
1445
|
|
1446 //=============================================================================
|
|
1447 //------------------------------PhaseIdealLoop---------------------------------
|
|
1448 // Create a PhaseLoop. Build the ideal Loop tree. Map each Ideal Node to
|
|
1449 // its corresponding LoopNode. If 'optimize' is true, do some loop cleanups.
|
|
1450 PhaseIdealLoop::PhaseIdealLoop( PhaseIterGVN &igvn, const PhaseIdealLoop *verify_me, bool do_split_ifs )
|
|
1451 : PhaseTransform(Ideal_Loop),
|
|
1452 _igvn(igvn),
|
|
1453 _dom_lca_tags(C->comp_arena()) {
|
|
1454 // Reset major-progress flag for the driver's heuristics
|
|
1455 C->clear_major_progress();
|
|
1456
|
|
1457 #ifndef PRODUCT
|
|
1458 // Capture for later assert
|
|
1459 uint unique = C->unique();
|
|
1460 _loop_invokes++;
|
|
1461 _loop_work += unique;
|
|
1462 #endif
|
|
1463
|
|
1464 // True if the method has at least 1 irreducible loop
|
|
1465 _has_irreducible_loops = false;
|
|
1466
|
|
1467 _created_loop_node = false;
|
|
1468
|
|
1469 Arena *a = Thread::current()->resource_area();
|
|
1470 VectorSet visited(a);
|
|
1471 // Pre-grow the mapping from Nodes to IdealLoopTrees.
|
|
1472 _nodes.map(C->unique(), NULL);
|
|
1473 memset(_nodes.adr(), 0, wordSize * C->unique());
|
|
1474
|
|
1475 // Pre-build the top-level outermost loop tree entry
|
|
1476 _ltree_root = new IdealLoopTree( this, C->root(), C->root() );
|
|
1477 // Do not need a safepoint at the top level
|
|
1478 _ltree_root->_has_sfpt = 1;
|
|
1479
|
|
1480 // Empty pre-order array
|
|
1481 allocate_preorders();
|
|
1482
|
|
1483 // Build a loop tree on the fly. Build a mapping from CFG nodes to
|
|
1484 // IdealLoopTree entries. Data nodes are NOT walked.
|
|
1485 build_loop_tree();
|
|
1486 // Check for bailout, and return
|
|
1487 if (C->failing()) {
|
|
1488 return;
|
|
1489 }
|
|
1490
|
|
1491 // No loops after all
|
|
1492 if( !_ltree_root->_child ) C->set_has_loops(false);
|
|
1493
|
|
1494 // There should always be an outer loop containing the Root and Return nodes.
|
|
1495 // If not, we have a degenerate empty program. Bail out in this case.
|
|
1496 if (!has_node(C->root())) {
|
|
1497 C->clear_major_progress();
|
|
1498 C->record_method_not_compilable("empty program detected during loop optimization");
|
|
1499 return;
|
|
1500 }
|
|
1501
|
|
1502 // Nothing to do, so get out
|
|
1503 if( !C->has_loops() && !do_split_ifs && !verify_me) {
|
|
1504 _igvn.optimize(); // Cleanup NeverBranches
|
|
1505 return;
|
|
1506 }
|
|
1507
|
|
1508 // Set loop nesting depth
|
|
1509 _ltree_root->set_nest( 0 );
|
|
1510
|
|
1511 // Split shared headers and insert loop landing pads.
|
|
1512 // Do not bother doing this on the Root loop of course.
|
|
1513 if( !verify_me && _ltree_root->_child ) {
|
|
1514 if( _ltree_root->_child->beautify_loops( this ) ) {
|
|
1515 // Re-build loop tree!
|
|
1516 _ltree_root->_child = NULL;
|
|
1517 _nodes.clear();
|
|
1518 reallocate_preorders();
|
|
1519 build_loop_tree();
|
|
1520 // Check for bailout, and return
|
|
1521 if (C->failing()) {
|
|
1522 return;
|
|
1523 }
|
|
1524 // Reset loop nesting depth
|
|
1525 _ltree_root->set_nest( 0 );
|
|
1526 }
|
|
1527 }
|
|
1528
|
|
1529 // Build Dominators for elision of NULL checks & loop finding.
|
|
1530 // Since nodes do not have a slot for immediate dominator, make
|
|
1531 // a persistant side array for that info indexed on node->_idx.
|
|
1532 _idom_size = C->unique();
|
|
1533 _idom = NEW_RESOURCE_ARRAY( Node*, _idom_size );
|
|
1534 _dom_depth = NEW_RESOURCE_ARRAY( uint, _idom_size );
|
|
1535 _dom_stk = NULL; // Allocated on demand in recompute_dom_depth
|
|
1536 memset( _dom_depth, 0, _idom_size * sizeof(uint) );
|
|
1537
|
|
1538 Dominators();
|
|
1539
|
|
1540 // As a side effect, Dominators removed any unreachable CFG paths
|
|
1541 // into RegionNodes. It doesn't do this test against Root, so
|
|
1542 // we do it here.
|
|
1543 for( uint i = 1; i < C->root()->req(); i++ ) {
|
|
1544 if( !_nodes[C->root()->in(i)->_idx] ) { // Dead path into Root?
|
|
1545 _igvn.hash_delete(C->root());
|
|
1546 C->root()->del_req(i);
|
|
1547 _igvn._worklist.push(C->root());
|
|
1548 i--; // Rerun same iteration on compressed edges
|
|
1549 }
|
|
1550 }
|
|
1551
|
|
1552 // Given dominators, try to find inner loops with calls that must
|
|
1553 // always be executed (call dominates loop tail). These loops do
|
|
1554 // not need a seperate safepoint.
|
|
1555 Node_List cisstack(a);
|
|
1556 _ltree_root->check_safepts(visited, cisstack);
|
|
1557
|
|
1558 // Walk the DATA nodes and place into loops. Find earliest control
|
|
1559 // node. For CFG nodes, the _nodes array starts out and remains
|
|
1560 // holding the associated IdealLoopTree pointer. For DATA nodes, the
|
|
1561 // _nodes array holds the earliest legal controlling CFG node.
|
|
1562
|
|
1563 // Allocate stack with enough space to avoid frequent realloc
|
|
1564 int stack_size = (C->unique() >> 1) + 16; // (unique>>1)+16 from Java2D stats
|
|
1565 Node_Stack nstack( a, stack_size );
|
|
1566
|
|
1567 visited.Clear();
|
|
1568 Node_List worklist(a);
|
|
1569 // Don't need C->root() on worklist since
|
|
1570 // it will be processed among C->top() inputs
|
|
1571 worklist.push( C->top() );
|
|
1572 visited.set( C->top()->_idx ); // Set C->top() as visited now
|
|
1573 build_loop_early( visited, worklist, nstack, verify_me );
|
|
1574
|
|
1575 // Given early legal placement, try finding counted loops. This placement
|
|
1576 // is good enough to discover most loop invariants.
|
|
1577 if( !verify_me )
|
|
1578 _ltree_root->counted_loop( this );
|
|
1579
|
|
1580 // Find latest loop placement. Find ideal loop placement.
|
|
1581 visited.Clear();
|
|
1582 init_dom_lca_tags();
|
|
1583 // Need C->root() on worklist when processing outs
|
|
1584 worklist.push( C->root() );
|
|
1585 NOT_PRODUCT( C->verify_graph_edges(); )
|
|
1586 worklist.push( C->top() );
|
|
1587 build_loop_late( visited, worklist, nstack, verify_me );
|
|
1588
|
|
1589 // clear out the dead code
|
|
1590 while(_deadlist.size()) {
|
|
1591 igvn.remove_globally_dead_node(_deadlist.pop());
|
|
1592 }
|
|
1593
|
|
1594 #ifndef PRODUCT
|
|
1595 C->verify_graph_edges();
|
|
1596 if( verify_me ) { // Nested verify pass?
|
|
1597 // Check to see if the verify mode is broken
|
|
1598 assert(C->unique() == unique, "non-optimize mode made Nodes? ? ?");
|
|
1599 return;
|
|
1600 }
|
|
1601 if( VerifyLoopOptimizations ) verify();
|
|
1602 #endif
|
|
1603
|
|
1604 if (ReassociateInvariants) {
|
|
1605 // Reassociate invariants and prep for split_thru_phi
|
|
1606 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) {
|
|
1607 IdealLoopTree* lpt = iter.current();
|
|
1608 if (!lpt->is_counted() || !lpt->is_inner()) continue;
|
|
1609
|
|
1610 lpt->reassociate_invariants(this);
|
|
1611
|
|
1612 // Because RCE opportunities can be masked by split_thru_phi,
|
|
1613 // look for RCE candidates and inhibit split_thru_phi
|
|
1614 // on just their loop-phi's for this pass of loop opts
|
|
1615 if( SplitIfBlocks && do_split_ifs ) {
|
|
1616 if (lpt->policy_range_check(this)) {
|
|
1617 lpt->_rce_candidate = true;
|
|
1618 }
|
|
1619 }
|
|
1620 }
|
|
1621 }
|
|
1622
|
|
1623 // Check for aggressive application of split-if and other transforms
|
|
1624 // that require basic-block info (like cloning through Phi's)
|
|
1625 if( SplitIfBlocks && do_split_ifs ) {
|
|
1626 visited.Clear();
|
|
1627 split_if_with_blocks( visited, nstack );
|
|
1628 NOT_PRODUCT( if( VerifyLoopOptimizations ) verify(); );
|
|
1629 }
|
|
1630
|
|
1631 // Perform iteration-splitting on inner loops. Split iterations to avoid
|
|
1632 // range checks or one-shot null checks.
|
|
1633
|
|
1634 // If split-if's didn't hack the graph too bad (no CFG changes)
|
|
1635 // then do loop opts.
|
|
1636 if( C->has_loops() && !C->major_progress() ) {
|
|
1637 memset( worklist.adr(), 0, worklist.Size()*sizeof(Node*) );
|
|
1638 _ltree_root->_child->iteration_split( this, worklist );
|
|
1639 // No verify after peeling! GCM has hoisted code out of the loop.
|
|
1640 // After peeling, the hoisted code could sink inside the peeled area.
|
|
1641 // The peeling code does not try to recompute the best location for
|
|
1642 // all the code before the peeled area, so the verify pass will always
|
|
1643 // complain about it.
|
|
1644 }
|
|
1645 // Do verify graph edges in any case
|
|
1646 NOT_PRODUCT( C->verify_graph_edges(); );
|
|
1647
|
|
1648 if( !do_split_ifs ) {
|
|
1649 // We saw major progress in Split-If to get here. We forced a
|
|
1650 // pass with unrolling and not split-if, however more split-if's
|
|
1651 // might make progress. If the unrolling didn't make progress
|
|
1652 // then the major-progress flag got cleared and we won't try
|
|
1653 // another round of Split-If. In particular the ever-common
|
|
1654 // instance-of/check-cast pattern requires at least 2 rounds of
|
|
1655 // Split-If to clear out.
|
|
1656 C->set_major_progress();
|
|
1657 }
|
|
1658
|
|
1659 // Repeat loop optimizations if new loops were seen
|
|
1660 if (created_loop_node()) {
|
|
1661 C->set_major_progress();
|
|
1662 }
|
|
1663
|
|
1664 // Convert scalar to superword operations
|
|
1665
|
|
1666 if (UseSuperWord && C->has_loops() && !C->major_progress()) {
|
|
1667 // SuperWord transform
|
|
1668 SuperWord sw(this);
|
|
1669 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) {
|
|
1670 IdealLoopTree* lpt = iter.current();
|
|
1671 if (lpt->is_counted()) {
|
|
1672 sw.transform_loop(lpt);
|
|
1673 }
|
|
1674 }
|
|
1675 }
|
|
1676
|
|
1677 // Cleanup any modified bits
|
|
1678 _igvn.optimize();
|
|
1679
|
|
1680 // Do not repeat loop optimizations if irreducible loops are present
|
|
1681 // by claiming no-progress.
|
|
1682 if( _has_irreducible_loops )
|
|
1683 C->clear_major_progress();
|
|
1684 }
|
|
1685
|
|
1686 #ifndef PRODUCT
|
|
1687 //------------------------------print_statistics-------------------------------
|
|
1688 int PhaseIdealLoop::_loop_invokes=0;// Count of PhaseIdealLoop invokes
|
|
1689 int PhaseIdealLoop::_loop_work=0; // Sum of PhaseIdealLoop x unique
|
|
1690 void PhaseIdealLoop::print_statistics() {
|
|
1691 tty->print_cr("PhaseIdealLoop=%d, sum _unique=%d", _loop_invokes, _loop_work);
|
|
1692 }
|
|
1693
|
|
1694 //------------------------------verify-----------------------------------------
|
|
1695 // Build a verify-only PhaseIdealLoop, and see that it agrees with me.
|
|
1696 static int fail; // debug only, so its multi-thread dont care
|
|
1697 void PhaseIdealLoop::verify() const {
|
|
1698 int old_progress = C->major_progress();
|
|
1699 ResourceMark rm;
|
|
1700 PhaseIdealLoop loop_verify( _igvn, this, false );
|
|
1701 VectorSet visited(Thread::current()->resource_area());
|
|
1702
|
|
1703 fail = 0;
|
|
1704 verify_compare( C->root(), &loop_verify, visited );
|
|
1705 assert( fail == 0, "verify loops failed" );
|
|
1706 // Verify loop structure is the same
|
|
1707 _ltree_root->verify_tree(loop_verify._ltree_root, NULL);
|
|
1708 // Reset major-progress. It was cleared by creating a verify version of
|
|
1709 // PhaseIdealLoop.
|
|
1710 for( int i=0; i<old_progress; i++ )
|
|
1711 C->set_major_progress();
|
|
1712 }
|
|
1713
|
|
1714 //------------------------------verify_compare---------------------------------
|
|
1715 // Make sure me and the given PhaseIdealLoop agree on key data structures
|
|
1716 void PhaseIdealLoop::verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const {
|
|
1717 if( !n ) return;
|
|
1718 if( visited.test_set( n->_idx ) ) return;
|
|
1719 if( !_nodes[n->_idx] ) { // Unreachable
|
|
1720 assert( !loop_verify->_nodes[n->_idx], "both should be unreachable" );
|
|
1721 return;
|
|
1722 }
|
|
1723
|
|
1724 uint i;
|
|
1725 for( i = 0; i < n->req(); i++ )
|
|
1726 verify_compare( n->in(i), loop_verify, visited );
|
|
1727
|
|
1728 // Check the '_nodes' block/loop structure
|
|
1729 i = n->_idx;
|
|
1730 if( has_ctrl(n) ) { // We have control; verify has loop or ctrl
|
|
1731 if( _nodes[i] != loop_verify->_nodes[i] &&
|
|
1732 get_ctrl_no_update(n) != loop_verify->get_ctrl_no_update(n) ) {
|
|
1733 tty->print("Mismatched control setting for: ");
|
|
1734 n->dump();
|
|
1735 if( fail++ > 10 ) return;
|
|
1736 Node *c = get_ctrl_no_update(n);
|
|
1737 tty->print("We have it as: ");
|
|
1738 if( c->in(0) ) c->dump();
|
|
1739 else tty->print_cr("N%d",c->_idx);
|
|
1740 tty->print("Verify thinks: ");
|
|
1741 if( loop_verify->has_ctrl(n) )
|
|
1742 loop_verify->get_ctrl_no_update(n)->dump();
|
|
1743 else
|
|
1744 loop_verify->get_loop_idx(n)->dump();
|
|
1745 tty->cr();
|
|
1746 }
|
|
1747 } else { // We have a loop
|
|
1748 IdealLoopTree *us = get_loop_idx(n);
|
|
1749 if( loop_verify->has_ctrl(n) ) {
|
|
1750 tty->print("Mismatched loop setting for: ");
|
|
1751 n->dump();
|
|
1752 if( fail++ > 10 ) return;
|
|
1753 tty->print("We have it as: ");
|
|
1754 us->dump();
|
|
1755 tty->print("Verify thinks: ");
|
|
1756 loop_verify->get_ctrl_no_update(n)->dump();
|
|
1757 tty->cr();
|
|
1758 } else if (!C->major_progress()) {
|
|
1759 // Loop selection can be messed up if we did a major progress
|
|
1760 // operation, like split-if. Do not verify in that case.
|
|
1761 IdealLoopTree *them = loop_verify->get_loop_idx(n);
|
|
1762 if( us->_head != them->_head || us->_tail != them->_tail ) {
|
|
1763 tty->print("Unequals loops for: ");
|
|
1764 n->dump();
|
|
1765 if( fail++ > 10 ) return;
|
|
1766 tty->print("We have it as: ");
|
|
1767 us->dump();
|
|
1768 tty->print("Verify thinks: ");
|
|
1769 them->dump();
|
|
1770 tty->cr();
|
|
1771 }
|
|
1772 }
|
|
1773 }
|
|
1774
|
|
1775 // Check for immediate dominators being equal
|
|
1776 if( i >= _idom_size ) {
|
|
1777 if( !n->is_CFG() ) return;
|
|
1778 tty->print("CFG Node with no idom: ");
|
|
1779 n->dump();
|
|
1780 return;
|
|
1781 }
|
|
1782 if( !n->is_CFG() ) return;
|
|
1783 if( n == C->root() ) return; // No IDOM here
|
|
1784
|
|
1785 assert(n->_idx == i, "sanity");
|
|
1786 Node *id = idom_no_update(n);
|
|
1787 if( id != loop_verify->idom_no_update(n) ) {
|
|
1788 tty->print("Unequals idoms for: ");
|
|
1789 n->dump();
|
|
1790 if( fail++ > 10 ) return;
|
|
1791 tty->print("We have it as: ");
|
|
1792 id->dump();
|
|
1793 tty->print("Verify thinks: ");
|
|
1794 loop_verify->idom_no_update(n)->dump();
|
|
1795 tty->cr();
|
|
1796 }
|
|
1797
|
|
1798 }
|
|
1799
|
|
1800 //------------------------------verify_tree------------------------------------
|
|
1801 // Verify that tree structures match. Because the CFG can change, siblings
|
|
1802 // within the loop tree can be reordered. We attempt to deal with that by
|
|
1803 // reordering the verify's loop tree if possible.
|
|
1804 void IdealLoopTree::verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const {
|
|
1805 assert( _parent == parent, "Badly formed loop tree" );
|
|
1806
|
|
1807 // Siblings not in same order? Attempt to re-order.
|
|
1808 if( _head != loop->_head ) {
|
|
1809 // Find _next pointer to update
|
|
1810 IdealLoopTree **pp = &loop->_parent->_child;
|
|
1811 while( *pp != loop )
|
|
1812 pp = &((*pp)->_next);
|
|
1813 // Find proper sibling to be next
|
|
1814 IdealLoopTree **nn = &loop->_next;
|
|
1815 while( (*nn) && (*nn)->_head != _head )
|
|
1816 nn = &((*nn)->_next);
|
|
1817
|
|
1818 // Check for no match.
|
|
1819 if( !(*nn) ) {
|
|
1820 // Annoyingly, irreducible loops can pick different headers
|
|
1821 // after a major_progress operation, so the rest of the loop
|
|
1822 // tree cannot be matched.
|
|
1823 if (_irreducible && Compile::current()->major_progress()) return;
|
|
1824 assert( 0, "failed to match loop tree" );
|
|
1825 }
|
|
1826
|
|
1827 // Move (*nn) to (*pp)
|
|
1828 IdealLoopTree *hit = *nn;
|
|
1829 *nn = hit->_next;
|
|
1830 hit->_next = loop;
|
|
1831 *pp = loop;
|
|
1832 loop = hit;
|
|
1833 // Now try again to verify
|
|
1834 }
|
|
1835
|
|
1836 assert( _head == loop->_head , "mismatched loop head" );
|
|
1837 Node *tail = _tail; // Inline a non-updating version of
|
|
1838 while( !tail->in(0) ) // the 'tail()' call.
|
|
1839 tail = tail->in(1);
|
|
1840 assert( tail == loop->_tail, "mismatched loop tail" );
|
|
1841
|
|
1842 // Counted loops that are guarded should be able to find their guards
|
|
1843 if( _head->is_CountedLoop() && _head->as_CountedLoop()->is_main_loop() ) {
|
|
1844 CountedLoopNode *cl = _head->as_CountedLoop();
|
|
1845 Node *init = cl->init_trip();
|
|
1846 Node *ctrl = cl->in(LoopNode::EntryControl);
|
|
1847 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" );
|
|
1848 Node *iff = ctrl->in(0);
|
|
1849 assert( iff->Opcode() == Op_If, "" );
|
|
1850 Node *bol = iff->in(1);
|
|
1851 assert( bol->Opcode() == Op_Bool, "" );
|
|
1852 Node *cmp = bol->in(1);
|
|
1853 assert( cmp->Opcode() == Op_CmpI, "" );
|
|
1854 Node *add = cmp->in(1);
|
|
1855 Node *opaq;
|
|
1856 if( add->Opcode() == Op_Opaque1 ) {
|
|
1857 opaq = add;
|
|
1858 } else {
|
|
1859 assert( add->Opcode() == Op_AddI || add->Opcode() == Op_ConI , "" );
|
|
1860 assert( add == init, "" );
|
|
1861 opaq = cmp->in(2);
|
|
1862 }
|
|
1863 assert( opaq->Opcode() == Op_Opaque1, "" );
|
|
1864
|
|
1865 }
|
|
1866
|
|
1867 if (_child != NULL) _child->verify_tree(loop->_child, this);
|
|
1868 if (_next != NULL) _next ->verify_tree(loop->_next, parent);
|
|
1869 // Innermost loops need to verify loop bodies,
|
|
1870 // but only if no 'major_progress'
|
|
1871 int fail = 0;
|
|
1872 if (!Compile::current()->major_progress() && _child == NULL) {
|
|
1873 for( uint i = 0; i < _body.size(); i++ ) {
|
|
1874 Node *n = _body.at(i);
|
|
1875 if (n->outcnt() == 0) continue; // Ignore dead
|
|
1876 uint j;
|
|
1877 for( j = 0; j < loop->_body.size(); j++ )
|
|
1878 if( loop->_body.at(j) == n )
|
|
1879 break;
|
|
1880 if( j == loop->_body.size() ) { // Not found in loop body
|
|
1881 // Last ditch effort to avoid assertion: Its possible that we
|
|
1882 // have some users (so outcnt not zero) but are still dead.
|
|
1883 // Try to find from root.
|
|
1884 if (Compile::current()->root()->find(n->_idx)) {
|
|
1885 fail++;
|
|
1886 tty->print("We have that verify does not: ");
|
|
1887 n->dump();
|
|
1888 }
|
|
1889 }
|
|
1890 }
|
|
1891 for( uint i2 = 0; i2 < loop->_body.size(); i2++ ) {
|
|
1892 Node *n = loop->_body.at(i2);
|
|
1893 if (n->outcnt() == 0) continue; // Ignore dead
|
|
1894 uint j;
|
|
1895 for( j = 0; j < _body.size(); j++ )
|
|
1896 if( _body.at(j) == n )
|
|
1897 break;
|
|
1898 if( j == _body.size() ) { // Not found in loop body
|
|
1899 // Last ditch effort to avoid assertion: Its possible that we
|
|
1900 // have some users (so outcnt not zero) but are still dead.
|
|
1901 // Try to find from root.
|
|
1902 if (Compile::current()->root()->find(n->_idx)) {
|
|
1903 fail++;
|
|
1904 tty->print("Verify has that we do not: ");
|
|
1905 n->dump();
|
|
1906 }
|
|
1907 }
|
|
1908 }
|
|
1909 assert( !fail, "loop body mismatch" );
|
|
1910 }
|
|
1911 }
|
|
1912
|
|
1913 #endif
|
|
1914
|
|
1915 //------------------------------set_idom---------------------------------------
|
|
1916 void PhaseIdealLoop::set_idom(Node* d, Node* n, uint dom_depth) {
|
|
1917 uint idx = d->_idx;
|
|
1918 if (idx >= _idom_size) {
|
|
1919 uint newsize = _idom_size<<1;
|
|
1920 while( idx >= newsize ) {
|
|
1921 newsize <<= 1;
|
|
1922 }
|
|
1923 _idom = REALLOC_RESOURCE_ARRAY( Node*, _idom,_idom_size,newsize);
|
|
1924 _dom_depth = REALLOC_RESOURCE_ARRAY( uint, _dom_depth,_idom_size,newsize);
|
|
1925 memset( _dom_depth + _idom_size, 0, (newsize - _idom_size) * sizeof(uint) );
|
|
1926 _idom_size = newsize;
|
|
1927 }
|
|
1928 _idom[idx] = n;
|
|
1929 _dom_depth[idx] = dom_depth;
|
|
1930 }
|
|
1931
|
|
1932 //------------------------------recompute_dom_depth---------------------------------------
|
|
1933 // The dominator tree is constructed with only parent pointers.
|
|
1934 // This recomputes the depth in the tree by first tagging all
|
|
1935 // nodes as "no depth yet" marker. The next pass then runs up
|
|
1936 // the dom tree from each node marked "no depth yet", and computes
|
|
1937 // the depth on the way back down.
|
|
1938 void PhaseIdealLoop::recompute_dom_depth() {
|
|
1939 uint no_depth_marker = C->unique();
|
|
1940 uint i;
|
|
1941 // Initialize depth to "no depth yet"
|
|
1942 for (i = 0; i < _idom_size; i++) {
|
|
1943 if (_dom_depth[i] > 0 && _idom[i] != NULL) {
|
|
1944 _dom_depth[i] = no_depth_marker;
|
|
1945 }
|
|
1946 }
|
|
1947 if (_dom_stk == NULL) {
|
|
1948 uint init_size = C->unique() / 100; // Guess that 1/100 is a reasonable initial size.
|
|
1949 if (init_size < 10) init_size = 10;
|
|
1950 _dom_stk = new (C->node_arena()) GrowableArray<uint>(C->node_arena(), init_size, 0, 0);
|
|
1951 }
|
|
1952 // Compute new depth for each node.
|
|
1953 for (i = 0; i < _idom_size; i++) {
|
|
1954 uint j = i;
|
|
1955 // Run up the dom tree to find a node with a depth
|
|
1956 while (_dom_depth[j] == no_depth_marker) {
|
|
1957 _dom_stk->push(j);
|
|
1958 j = _idom[j]->_idx;
|
|
1959 }
|
|
1960 // Compute the depth on the way back down this tree branch
|
|
1961 uint dd = _dom_depth[j] + 1;
|
|
1962 while (_dom_stk->length() > 0) {
|
|
1963 uint j = _dom_stk->pop();
|
|
1964 _dom_depth[j] = dd;
|
|
1965 dd++;
|
|
1966 }
|
|
1967 }
|
|
1968 }
|
|
1969
|
|
1970 //------------------------------sort-------------------------------------------
|
|
1971 // Insert 'loop' into the existing loop tree. 'innermost' is a leaf of the
|
|
1972 // loop tree, not the root.
|
|
1973 IdealLoopTree *PhaseIdealLoop::sort( IdealLoopTree *loop, IdealLoopTree *innermost ) {
|
|
1974 if( !innermost ) return loop; // New innermost loop
|
|
1975
|
|
1976 int loop_preorder = get_preorder(loop->_head); // Cache pre-order number
|
|
1977 assert( loop_preorder, "not yet post-walked loop" );
|
|
1978 IdealLoopTree **pp = &innermost; // Pointer to previous next-pointer
|
|
1979 IdealLoopTree *l = *pp; // Do I go before or after 'l'?
|
|
1980
|
|
1981 // Insert at start of list
|
|
1982 while( l ) { // Insertion sort based on pre-order
|
|
1983 if( l == loop ) return innermost; // Already on list!
|
|
1984 int l_preorder = get_preorder(l->_head); // Cache pre-order number
|
|
1985 assert( l_preorder, "not yet post-walked l" );
|
|
1986 // Check header pre-order number to figure proper nesting
|
|
1987 if( loop_preorder > l_preorder )
|
|
1988 break; // End of insertion
|
|
1989 // If headers tie (e.g., shared headers) check tail pre-order numbers.
|
|
1990 // Since I split shared headers, you'd think this could not happen.
|
|
1991 // BUT: I must first do the preorder numbering before I can discover I
|
|
1992 // have shared headers, so the split headers all get the same preorder
|
|
1993 // number as the RegionNode they split from.
|
|
1994 if( loop_preorder == l_preorder &&
|
|
1995 get_preorder(loop->_tail) < get_preorder(l->_tail) )
|
|
1996 break; // Also check for shared headers (same pre#)
|
|
1997 pp = &l->_parent; // Chain up list
|
|
1998 l = *pp;
|
|
1999 }
|
|
2000 // Link into list
|
|
2001 // Point predecessor to me
|
|
2002 *pp = loop;
|
|
2003 // Point me to successor
|
|
2004 IdealLoopTree *p = loop->_parent;
|
|
2005 loop->_parent = l; // Point me to successor
|
|
2006 if( p ) sort( p, innermost ); // Insert my parents into list as well
|
|
2007 return innermost;
|
|
2008 }
|
|
2009
|
|
2010 //------------------------------build_loop_tree--------------------------------
|
|
2011 // I use a modified Vick/Tarjan algorithm. I need pre- and a post- visit
|
|
2012 // bits. The _nodes[] array is mapped by Node index and holds a NULL for
|
|
2013 // not-yet-pre-walked, pre-order # for pre-but-not-post-walked and holds the
|
|
2014 // tightest enclosing IdealLoopTree for post-walked.
|
|
2015 //
|
|
2016 // During my forward walk I do a short 1-layer lookahead to see if I can find
|
|
2017 // a loop backedge with that doesn't have any work on the backedge. This
|
|
2018 // helps me construct nested loops with shared headers better.
|
|
2019 //
|
|
2020 // Once I've done the forward recursion, I do the post-work. For each child
|
|
2021 // I check to see if there is a backedge. Backedges define a loop! I
|
|
2022 // insert an IdealLoopTree at the target of the backedge.
|
|
2023 //
|
|
2024 // During the post-work I also check to see if I have several children
|
|
2025 // belonging to different loops. If so, then this Node is a decision point
|
|
2026 // where control flow can choose to change loop nests. It is at this
|
|
2027 // decision point where I can figure out how loops are nested. At this
|
|
2028 // time I can properly order the different loop nests from my children.
|
|
2029 // Note that there may not be any backedges at the decision point!
|
|
2030 //
|
|
2031 // Since the decision point can be far removed from the backedges, I can't
|
|
2032 // order my loops at the time I discover them. Thus at the decision point
|
|
2033 // I need to inspect loop header pre-order numbers to properly nest my
|
|
2034 // loops. This means I need to sort my childrens' loops by pre-order.
|
|
2035 // The sort is of size number-of-control-children, which generally limits
|
|
2036 // it to size 2 (i.e., I just choose between my 2 target loops).
|
|
2037 void PhaseIdealLoop::build_loop_tree() {
|
|
2038 // Allocate stack of size C->unique()/2 to avoid frequent realloc
|
|
2039 GrowableArray <Node *> bltstack(C->unique() >> 1);
|
|
2040 Node *n = C->root();
|
|
2041 bltstack.push(n);
|
|
2042 int pre_order = 1;
|
|
2043 int stack_size;
|
|
2044
|
|
2045 while ( ( stack_size = bltstack.length() ) != 0 ) {
|
|
2046 n = bltstack.top(); // Leave node on stack
|
|
2047 if ( !is_visited(n) ) {
|
|
2048 // ---- Pre-pass Work ----
|
|
2049 // Pre-walked but not post-walked nodes need a pre_order number.
|
|
2050
|
|
2051 set_preorder_visited( n, pre_order ); // set as visited
|
|
2052
|
|
2053 // ---- Scan over children ----
|
|
2054 // Scan first over control projections that lead to loop headers.
|
|
2055 // This helps us find inner-to-outer loops with shared headers better.
|
|
2056
|
|
2057 // Scan children's children for loop headers.
|
|
2058 for ( int i = n->outcnt() - 1; i >= 0; --i ) {
|
|
2059 Node* m = n->raw_out(i); // Child
|
|
2060 if( m->is_CFG() && !is_visited(m) ) { // Only for CFG children
|
|
2061 // Scan over children's children to find loop
|
|
2062 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
|
|
2063 Node* l = m->fast_out(j);
|
|
2064 if( is_visited(l) && // Been visited?
|
|
2065 !is_postvisited(l) && // But not post-visited
|
|
2066 get_preorder(l) < pre_order ) { // And smaller pre-order
|
|
2067 // Found! Scan the DFS down this path before doing other paths
|
|
2068 bltstack.push(m);
|
|
2069 break;
|
|
2070 }
|
|
2071 }
|
|
2072 }
|
|
2073 }
|
|
2074 pre_order++;
|
|
2075 }
|
|
2076 else if ( !is_postvisited(n) ) {
|
|
2077 // Note: build_loop_tree_impl() adds out edges on rare occasions,
|
|
2078 // such as com.sun.rsasign.am::a.
|
|
2079 // For non-recursive version, first, process current children.
|
|
2080 // On next iteration, check if additional children were added.
|
|
2081 for ( int k = n->outcnt() - 1; k >= 0; --k ) {
|
|
2082 Node* u = n->raw_out(k);
|
|
2083 if ( u->is_CFG() && !is_visited(u) ) {
|
|
2084 bltstack.push(u);
|
|
2085 }
|
|
2086 }
|
|
2087 if ( bltstack.length() == stack_size ) {
|
|
2088 // There were no additional children, post visit node now
|
|
2089 (void)bltstack.pop(); // Remove node from stack
|
|
2090 pre_order = build_loop_tree_impl( n, pre_order );
|
|
2091 // Check for bailout
|
|
2092 if (C->failing()) {
|
|
2093 return;
|
|
2094 }
|
|
2095 // Check to grow _preorders[] array for the case when
|
|
2096 // build_loop_tree_impl() adds new nodes.
|
|
2097 check_grow_preorders();
|
|
2098 }
|
|
2099 }
|
|
2100 else {
|
|
2101 (void)bltstack.pop(); // Remove post-visited node from stack
|
|
2102 }
|
|
2103 }
|
|
2104 }
|
|
2105
|
|
2106 //------------------------------build_loop_tree_impl---------------------------
|
|
2107 int PhaseIdealLoop::build_loop_tree_impl( Node *n, int pre_order ) {
|
|
2108 // ---- Post-pass Work ----
|
|
2109 // Pre-walked but not post-walked nodes need a pre_order number.
|
|
2110
|
|
2111 // Tightest enclosing loop for this Node
|
|
2112 IdealLoopTree *innermost = NULL;
|
|
2113
|
|
2114 // For all children, see if any edge is a backedge. If so, make a loop
|
|
2115 // for it. Then find the tightest enclosing loop for the self Node.
|
|
2116 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
|
|
2117 Node* m = n->fast_out(i); // Child
|
|
2118 if( n == m ) continue; // Ignore control self-cycles
|
|
2119 if( !m->is_CFG() ) continue;// Ignore non-CFG edges
|
|
2120
|
|
2121 IdealLoopTree *l; // Child's loop
|
|
2122 if( !is_postvisited(m) ) { // Child visited but not post-visited?
|
|
2123 // Found a backedge
|
|
2124 assert( get_preorder(m) < pre_order, "should be backedge" );
|
|
2125 // Check for the RootNode, which is already a LoopNode and is allowed
|
|
2126 // to have multiple "backedges".
|
|
2127 if( m == C->root()) { // Found the root?
|
|
2128 l = _ltree_root; // Root is the outermost LoopNode
|
|
2129 } else { // Else found a nested loop
|
|
2130 // Insert a LoopNode to mark this loop.
|
|
2131 l = new IdealLoopTree(this, m, n);
|
|
2132 } // End of Else found a nested loop
|
|
2133 if( !has_loop(m) ) // If 'm' does not already have a loop set
|
|
2134 set_loop(m, l); // Set loop header to loop now
|
|
2135
|
|
2136 } else { // Else not a nested loop
|
|
2137 if( !_nodes[m->_idx] ) continue; // Dead code has no loop
|
|
2138 l = get_loop(m); // Get previously determined loop
|
|
2139 // If successor is header of a loop (nest), move up-loop till it
|
|
2140 // is a member of some outer enclosing loop. Since there are no
|
|
2141 // shared headers (I've split them already) I only need to go up
|
|
2142 // at most 1 level.
|
|
2143 while( l && l->_head == m ) // Successor heads loop?
|
|
2144 l = l->_parent; // Move up 1 for me
|
|
2145 // If this loop is not properly parented, then this loop
|
|
2146 // has no exit path out, i.e. its an infinite loop.
|
|
2147 if( !l ) {
|
|
2148 // Make loop "reachable" from root so the CFG is reachable. Basically
|
|
2149 // insert a bogus loop exit that is never taken. 'm', the loop head,
|
|
2150 // points to 'n', one (of possibly many) fall-in paths. There may be
|
|
2151 // many backedges as well.
|
|
2152
|
|
2153 // Here I set the loop to be the root loop. I could have, after
|
|
2154 // inserting a bogus loop exit, restarted the recursion and found my
|
|
2155 // new loop exit. This would make the infinite loop a first-class
|
|
2156 // loop and it would then get properly optimized. What's the use of
|
|
2157 // optimizing an infinite loop?
|
|
2158 l = _ltree_root; // Oops, found infinite loop
|
|
2159
|
|
2160 // Insert the NeverBranch between 'm' and it's control user.
|
|
2161 NeverBranchNode *iff = new (C, 1) NeverBranchNode( m );
|
|
2162 _igvn.register_new_node_with_optimizer(iff);
|
|
2163 set_loop(iff, l);
|
|
2164 Node *if_t = new (C, 1) CProjNode( iff, 0 );
|
|
2165 _igvn.register_new_node_with_optimizer(if_t);
|
|
2166 set_loop(if_t, l);
|
|
2167
|
|
2168 Node* cfg = NULL; // Find the One True Control User of m
|
|
2169 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
|
|
2170 Node* x = m->fast_out(j);
|
|
2171 if (x->is_CFG() && x != m && x != iff)
|
|
2172 { cfg = x; break; }
|
|
2173 }
|
|
2174 assert(cfg != NULL, "must find the control user of m");
|
|
2175 uint k = 0; // Probably cfg->in(0)
|
|
2176 while( cfg->in(k) != m ) k++; // But check incase cfg is a Region
|
|
2177 cfg->set_req( k, if_t ); // Now point to NeverBranch
|
|
2178
|
|
2179 // Now create the never-taken loop exit
|
|
2180 Node *if_f = new (C, 1) CProjNode( iff, 1 );
|
|
2181 _igvn.register_new_node_with_optimizer(if_f);
|
|
2182 set_loop(if_f, l);
|
|
2183 // Find frame ptr for Halt. Relies on the optimizer
|
|
2184 // V-N'ing. Easier and quicker than searching through
|
|
2185 // the program structure.
|
|
2186 Node *frame = new (C, 1) ParmNode( C->start(), TypeFunc::FramePtr );
|
|
2187 _igvn.register_new_node_with_optimizer(frame);
|
|
2188 // Halt & Catch Fire
|
|
2189 Node *halt = new (C, TypeFunc::Parms) HaltNode( if_f, frame );
|
|
2190 _igvn.register_new_node_with_optimizer(halt);
|
|
2191 set_loop(halt, l);
|
|
2192 C->root()->add_req(halt);
|
|
2193 set_loop(C->root(), _ltree_root);
|
|
2194 }
|
|
2195 }
|
|
2196 // Weeny check for irreducible. This child was already visited (this
|
|
2197 // IS the post-work phase). Is this child's loop header post-visited
|
|
2198 // as well? If so, then I found another entry into the loop.
|
|
2199 while( is_postvisited(l->_head) ) {
|
|
2200 // found irreducible
|
|
2201 l->_irreducible = true;
|
|
2202 l = l->_parent;
|
|
2203 _has_irreducible_loops = true;
|
|
2204 // Check for bad CFG here to prevent crash, and bailout of compile
|
|
2205 if (l == NULL) {
|
|
2206 C->record_method_not_compilable("unhandled CFG detected during loop optimization");
|
|
2207 return pre_order;
|
|
2208 }
|
|
2209 }
|
|
2210
|
|
2211 // This Node might be a decision point for loops. It is only if
|
|
2212 // it's children belong to several different loops. The sort call
|
|
2213 // does a trivial amount of work if there is only 1 child or all
|
|
2214 // children belong to the same loop. If however, the children
|
|
2215 // belong to different loops, the sort call will properly set the
|
|
2216 // _parent pointers to show how the loops nest.
|
|
2217 //
|
|
2218 // In any case, it returns the tightest enclosing loop.
|
|
2219 innermost = sort( l, innermost );
|
|
2220 }
|
|
2221
|
|
2222 // Def-use info will have some dead stuff; dead stuff will have no
|
|
2223 // loop decided on.
|
|
2224
|
|
2225 // Am I a loop header? If so fix up my parent's child and next ptrs.
|
|
2226 if( innermost && innermost->_head == n ) {
|
|
2227 assert( get_loop(n) == innermost, "" );
|
|
2228 IdealLoopTree *p = innermost->_parent;
|
|
2229 IdealLoopTree *l = innermost;
|
|
2230 while( p && l->_head == n ) {
|
|
2231 l->_next = p->_child; // Put self on parents 'next child'
|
|
2232 p->_child = l; // Make self as first child of parent
|
|
2233 l = p; // Now walk up the parent chain
|
|
2234 p = l->_parent;
|
|
2235 }
|
|
2236 } else {
|
|
2237 // Note that it is possible for a LoopNode to reach here, if the
|
|
2238 // backedge has been made unreachable (hence the LoopNode no longer
|
|
2239 // denotes a Loop, and will eventually be removed).
|
|
2240
|
|
2241 // Record tightest enclosing loop for self. Mark as post-visited.
|
|
2242 set_loop(n, innermost);
|
|
2243 // Also record has_call flag early on
|
|
2244 if( innermost ) {
|
|
2245 if( n->is_Call() && !n->is_CallLeaf() && !n->is_macro() ) {
|
|
2246 // Do not count uncommon calls
|
|
2247 if( !n->is_CallStaticJava() || !n->as_CallStaticJava()->_name ) {
|
|
2248 Node *iff = n->in(0)->in(0);
|
|
2249 if( !iff->is_If() ||
|
|
2250 (n->in(0)->Opcode() == Op_IfFalse &&
|
|
2251 (1.0 - iff->as_If()->_prob) >= 0.01) ||
|
|
2252 (iff->as_If()->_prob >= 0.01) )
|
|
2253 innermost->_has_call = 1;
|
|
2254 }
|
|
2255 }
|
|
2256 }
|
|
2257 }
|
|
2258
|
|
2259 // Flag as post-visited now
|
|
2260 set_postvisited(n);
|
|
2261 return pre_order;
|
|
2262 }
|
|
2263
|
|
2264
|
|
2265 //------------------------------build_loop_early-------------------------------
|
|
2266 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping.
|
|
2267 // First pass computes the earliest controlling node possible. This is the
|
|
2268 // controlling input with the deepest dominating depth.
|
|
2269 void PhaseIdealLoop::build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack, const PhaseIdealLoop *verify_me ) {
|
|
2270 while (worklist.size() != 0) {
|
|
2271 // Use local variables nstack_top_n & nstack_top_i to cache values
|
|
2272 // on nstack's top.
|
|
2273 Node *nstack_top_n = worklist.pop();
|
|
2274 uint nstack_top_i = 0;
|
|
2275 //while_nstack_nonempty:
|
|
2276 while (true) {
|
|
2277 // Get parent node and next input's index from stack's top.
|
|
2278 Node *n = nstack_top_n;
|
|
2279 uint i = nstack_top_i;
|
|
2280 uint cnt = n->req(); // Count of inputs
|
|
2281 if (i == 0) { // Pre-process the node.
|
|
2282 if( has_node(n) && // Have either loop or control already?
|
|
2283 !has_ctrl(n) ) { // Have loop picked out already?
|
|
2284 // During "merge_many_backedges" we fold up several nested loops
|
|
2285 // into a single loop. This makes the members of the original
|
|
2286 // loop bodies pointing to dead loops; they need to move up
|
|
2287 // to the new UNION'd larger loop. I set the _head field of these
|
|
2288 // dead loops to NULL and the _parent field points to the owning
|
|
2289 // loop. Shades of UNION-FIND algorithm.
|
|
2290 IdealLoopTree *ilt;
|
|
2291 while( !(ilt = get_loop(n))->_head ) {
|
|
2292 // Normally I would use a set_loop here. But in this one special
|
|
2293 // case, it is legal (and expected) to change what loop a Node
|
|
2294 // belongs to.
|
|
2295 _nodes.map(n->_idx, (Node*)(ilt->_parent) );
|
|
2296 }
|
|
2297 // Remove safepoints ONLY if I've already seen I don't need one.
|
|
2298 // (the old code here would yank a 2nd safepoint after seeing a
|
|
2299 // first one, even though the 1st did not dominate in the loop body
|
|
2300 // and thus could be avoided indefinitely)
|
|
2301 if( !verify_me && ilt->_has_sfpt && n->Opcode() == Op_SafePoint &&
|
|
2302 is_deleteable_safept(n)) {
|
|
2303 Node *in = n->in(TypeFunc::Control);
|
|
2304 lazy_replace(n,in); // Pull safepoint now
|
|
2305 // Carry on with the recursion "as if" we are walking
|
|
2306 // only the control input
|
|
2307 if( !visited.test_set( in->_idx ) ) {
|
|
2308 worklist.push(in); // Visit this guy later, using worklist
|
|
2309 }
|
|
2310 // Get next node from nstack:
|
|
2311 // - skip n's inputs processing by setting i > cnt;
|
|
2312 // - we also will not call set_early_ctrl(n) since
|
|
2313 // has_node(n) == true (see the condition above).
|
|
2314 i = cnt + 1;
|
|
2315 }
|
|
2316 }
|
|
2317 } // if (i == 0)
|
|
2318
|
|
2319 // Visit all inputs
|
|
2320 bool done = true; // Assume all n's inputs will be processed
|
|
2321 while (i < cnt) {
|
|
2322 Node *in = n->in(i);
|
|
2323 ++i;
|
|
2324 if (in == NULL) continue;
|
|
2325 if (in->pinned() && !in->is_CFG())
|
|
2326 set_ctrl(in, in->in(0));
|
|
2327 int is_visited = visited.test_set( in->_idx );
|
|
2328 if (!has_node(in)) { // No controlling input yet?
|
|
2329 assert( !in->is_CFG(), "CFG Node with no controlling input?" );
|
|
2330 assert( !is_visited, "visit only once" );
|
|
2331 nstack.push(n, i); // Save parent node and next input's index.
|
|
2332 nstack_top_n = in; // Process current input now.
|
|
2333 nstack_top_i = 0;
|
|
2334 done = false; // Not all n's inputs processed.
|
|
2335 break; // continue while_nstack_nonempty;
|
|
2336 } else if (!is_visited) {
|
|
2337 // This guy has a location picked out for him, but has not yet
|
|
2338 // been visited. Happens to all CFG nodes, for instance.
|
|
2339 // Visit him using the worklist instead of recursion, to break
|
|
2340 // cycles. Since he has a location already we do not need to
|
|
2341 // find his location before proceeding with the current Node.
|
|
2342 worklist.push(in); // Visit this guy later, using worklist
|
|
2343 }
|
|
2344 }
|
|
2345 if (done) {
|
|
2346 // All of n's inputs have been processed, complete post-processing.
|
|
2347
|
|
2348 // Compute earilest point this Node can go.
|
|
2349 // CFG, Phi, pinned nodes already know their controlling input.
|
|
2350 if (!has_node(n)) {
|
|
2351 // Record earliest legal location
|
|
2352 set_early_ctrl( n );
|
|
2353 }
|
|
2354 if (nstack.is_empty()) {
|
|
2355 // Finished all nodes on stack.
|
|
2356 // Process next node on the worklist.
|
|
2357 break;
|
|
2358 }
|
|
2359 // Get saved parent node and next input's index.
|
|
2360 nstack_top_n = nstack.node();
|
|
2361 nstack_top_i = nstack.index();
|
|
2362 nstack.pop();
|
|
2363 }
|
|
2364 } // while (true)
|
|
2365 }
|
|
2366 }
|
|
2367
|
|
2368 //------------------------------dom_lca_internal--------------------------------
|
|
2369 // Pair-wise LCA
|
|
2370 Node *PhaseIdealLoop::dom_lca_internal( Node *n1, Node *n2 ) const {
|
|
2371 if( !n1 ) return n2; // Handle NULL original LCA
|
|
2372 assert( n1->is_CFG(), "" );
|
|
2373 assert( n2->is_CFG(), "" );
|
|
2374 // find LCA of all uses
|
|
2375 uint d1 = dom_depth(n1);
|
|
2376 uint d2 = dom_depth(n2);
|
|
2377 while (n1 != n2) {
|
|
2378 if (d1 > d2) {
|
|
2379 n1 = idom(n1);
|
|
2380 d1 = dom_depth(n1);
|
|
2381 } else if (d1 < d2) {
|
|
2382 n2 = idom(n2);
|
|
2383 d2 = dom_depth(n2);
|
|
2384 } else {
|
|
2385 // Here d1 == d2. Due to edits of the dominator-tree, sections
|
|
2386 // of the tree might have the same depth. These sections have
|
|
2387 // to be searched more carefully.
|
|
2388
|
|
2389 // Scan up all the n1's with equal depth, looking for n2.
|
|
2390 Node *t1 = idom(n1);
|
|
2391 while (dom_depth(t1) == d1) {
|
|
2392 if (t1 == n2) return n2;
|
|
2393 t1 = idom(t1);
|
|
2394 }
|
|
2395 // Scan up all the n2's with equal depth, looking for n1.
|
|
2396 Node *t2 = idom(n2);
|
|
2397 while (dom_depth(t2) == d2) {
|
|
2398 if (t2 == n1) return n1;
|
|
2399 t2 = idom(t2);
|
|
2400 }
|
|
2401 // Move up to a new dominator-depth value as well as up the dom-tree.
|
|
2402 n1 = t1;
|
|
2403 n2 = t2;
|
|
2404 d1 = dom_depth(n1);
|
|
2405 d2 = dom_depth(n2);
|
|
2406 }
|
|
2407 }
|
|
2408 return n1;
|
|
2409 }
|
|
2410
|
|
2411 //------------------------------compute_idom-----------------------------------
|
|
2412 // Locally compute IDOM using dom_lca call. Correct only if the incoming
|
|
2413 // IDOMs are correct.
|
|
2414 Node *PhaseIdealLoop::compute_idom( Node *region ) const {
|
|
2415 assert( region->is_Region(), "" );
|
|
2416 Node *LCA = NULL;
|
|
2417 for( uint i = 1; i < region->req(); i++ ) {
|
|
2418 if( region->in(i) != C->top() )
|
|
2419 LCA = dom_lca( LCA, region->in(i) );
|
|
2420 }
|
|
2421 return LCA;
|
|
2422 }
|
|
2423
|
|
2424 //------------------------------get_late_ctrl----------------------------------
|
|
2425 // Compute latest legal control.
|
|
2426 Node *PhaseIdealLoop::get_late_ctrl( Node *n, Node *early ) {
|
|
2427 assert(early != NULL, "early control should not be NULL");
|
|
2428
|
|
2429 // Compute LCA over list of uses
|
|
2430 Node *LCA = NULL;
|
|
2431 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && LCA != early; i++) {
|
|
2432 Node* c = n->fast_out(i);
|
|
2433 if (_nodes[c->_idx] == NULL)
|
|
2434 continue; // Skip the occasional dead node
|
|
2435 if( c->is_Phi() ) { // For Phis, we must land above on the path
|
|
2436 for( uint j=1; j<c->req(); j++ ) {// For all inputs
|
|
2437 if( c->in(j) == n ) { // Found matching input?
|
|
2438 Node *use = c->in(0)->in(j);
|
|
2439 LCA = dom_lca_for_get_late_ctrl( LCA, use, n );
|
|
2440 }
|
|
2441 }
|
|
2442 } else {
|
|
2443 // For CFG data-users, use is in the block just prior
|
|
2444 Node *use = has_ctrl(c) ? get_ctrl(c) : c->in(0);
|
|
2445 LCA = dom_lca_for_get_late_ctrl( LCA, use, n );
|
|
2446 }
|
|
2447 }
|
|
2448
|
|
2449 // if this is a load, check for anti-dependent stores
|
|
2450 // We use a conservative algorithm to identify potential interfering
|
|
2451 // instructions and for rescheduling the load. The users of the memory
|
|
2452 // input of this load are examined. Any use which is not a load and is
|
|
2453 // dominated by early is considered a potentially interfering store.
|
|
2454 // This can produce false positives.
|
|
2455 if (n->is_Load() && LCA != early) {
|
|
2456 Node_List worklist;
|
|
2457
|
|
2458 Node *mem = n->in(MemNode::Memory);
|
|
2459 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) {
|
|
2460 Node* s = mem->fast_out(i);
|
|
2461 worklist.push(s);
|
|
2462 }
|
|
2463 while(worklist.size() != 0 && LCA != early) {
|
|
2464 Node* s = worklist.pop();
|
|
2465 if (s->is_Load()) {
|
|
2466 continue;
|
|
2467 } else if (s->is_MergeMem()) {
|
|
2468 for (DUIterator_Fast imax, i = s->fast_outs(imax); i < imax; i++) {
|
|
2469 Node* s1 = s->fast_out(i);
|
|
2470 worklist.push(s1);
|
|
2471 }
|
|
2472 } else {
|
|
2473 Node *sctrl = has_ctrl(s) ? get_ctrl(s) : s->in(0);
|
|
2474 assert(sctrl != NULL || s->outcnt() == 0, "must have control");
|
|
2475 if (sctrl != NULL && !sctrl->is_top() && is_dominator(early, sctrl)) {
|
|
2476 LCA = dom_lca_for_get_late_ctrl(LCA, sctrl, n);
|
|
2477 }
|
|
2478 }
|
|
2479 }
|
|
2480 }
|
|
2481
|
|
2482 assert(LCA == find_non_split_ctrl(LCA), "unexpected late control");
|
|
2483 return LCA;
|
|
2484 }
|
|
2485
|
|
2486 // true if CFG node d dominates CFG node n
|
|
2487 bool PhaseIdealLoop::is_dominator(Node *d, Node *n) {
|
|
2488 if (d == n)
|
|
2489 return true;
|
|
2490 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes");
|
|
2491 uint dd = dom_depth(d);
|
|
2492 while (dom_depth(n) >= dd) {
|
|
2493 if (n == d)
|
|
2494 return true;
|
|
2495 n = idom(n);
|
|
2496 }
|
|
2497 return false;
|
|
2498 }
|
|
2499
|
|
2500 //------------------------------dom_lca_for_get_late_ctrl_internal-------------
|
|
2501 // Pair-wise LCA with tags.
|
|
2502 // Tag each index with the node 'tag' currently being processed
|
|
2503 // before advancing up the dominator chain using idom().
|
|
2504 // Later calls that find a match to 'tag' know that this path has already
|
|
2505 // been considered in the current LCA (which is input 'n1' by convention).
|
|
2506 // Since get_late_ctrl() is only called once for each node, the tag array
|
|
2507 // does not need to be cleared between calls to get_late_ctrl().
|
|
2508 // Algorithm trades a larger constant factor for better asymptotic behavior
|
|
2509 //
|
|
2510 Node *PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal( Node *n1, Node *n2, Node *tag ) {
|
|
2511 uint d1 = dom_depth(n1);
|
|
2512 uint d2 = dom_depth(n2);
|
|
2513
|
|
2514 do {
|
|
2515 if (d1 > d2) {
|
|
2516 // current lca is deeper than n2
|
|
2517 _dom_lca_tags.map(n1->_idx, tag);
|
|
2518 n1 = idom(n1);
|
|
2519 d1 = dom_depth(n1);
|
|
2520 } else if (d1 < d2) {
|
|
2521 // n2 is deeper than current lca
|
|
2522 Node *memo = _dom_lca_tags[n2->_idx];
|
|
2523 if( memo == tag ) {
|
|
2524 return n1; // Return the current LCA
|
|
2525 }
|
|
2526 _dom_lca_tags.map(n2->_idx, tag);
|
|
2527 n2 = idom(n2);
|
|
2528 d2 = dom_depth(n2);
|
|
2529 } else {
|
|
2530 // Here d1 == d2. Due to edits of the dominator-tree, sections
|
|
2531 // of the tree might have the same depth. These sections have
|
|
2532 // to be searched more carefully.
|
|
2533
|
|
2534 // Scan up all the n1's with equal depth, looking for n2.
|
|
2535 _dom_lca_tags.map(n1->_idx, tag);
|
|
2536 Node *t1 = idom(n1);
|
|
2537 while (dom_depth(t1) == d1) {
|
|
2538 if (t1 == n2) return n2;
|
|
2539 _dom_lca_tags.map(t1->_idx, tag);
|
|
2540 t1 = idom(t1);
|
|
2541 }
|
|
2542 // Scan up all the n2's with equal depth, looking for n1.
|
|
2543 _dom_lca_tags.map(n2->_idx, tag);
|
|
2544 Node *t2 = idom(n2);
|
|
2545 while (dom_depth(t2) == d2) {
|
|
2546 if (t2 == n1) return n1;
|
|
2547 _dom_lca_tags.map(t2->_idx, tag);
|
|
2548 t2 = idom(t2);
|
|
2549 }
|
|
2550 // Move up to a new dominator-depth value as well as up the dom-tree.
|
|
2551 n1 = t1;
|
|
2552 n2 = t2;
|
|
2553 d1 = dom_depth(n1);
|
|
2554 d2 = dom_depth(n2);
|
|
2555 }
|
|
2556 } while (n1 != n2);
|
|
2557 return n1;
|
|
2558 }
|
|
2559
|
|
2560 //------------------------------init_dom_lca_tags------------------------------
|
|
2561 // Tag could be a node's integer index, 32bits instead of 64bits in some cases
|
|
2562 // Intended use does not involve any growth for the array, so it could
|
|
2563 // be of fixed size.
|
|
2564 void PhaseIdealLoop::init_dom_lca_tags() {
|
|
2565 uint limit = C->unique() + 1;
|
|
2566 _dom_lca_tags.map( limit, NULL );
|
|
2567 #ifdef ASSERT
|
|
2568 for( uint i = 0; i < limit; ++i ) {
|
|
2569 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer");
|
|
2570 }
|
|
2571 #endif // ASSERT
|
|
2572 }
|
|
2573
|
|
2574 //------------------------------clear_dom_lca_tags------------------------------
|
|
2575 // Tag could be a node's integer index, 32bits instead of 64bits in some cases
|
|
2576 // Intended use does not involve any growth for the array, so it could
|
|
2577 // be of fixed size.
|
|
2578 void PhaseIdealLoop::clear_dom_lca_tags() {
|
|
2579 uint limit = C->unique() + 1;
|
|
2580 _dom_lca_tags.map( limit, NULL );
|
|
2581 _dom_lca_tags.clear();
|
|
2582 #ifdef ASSERT
|
|
2583 for( uint i = 0; i < limit; ++i ) {
|
|
2584 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer");
|
|
2585 }
|
|
2586 #endif // ASSERT
|
|
2587 }
|
|
2588
|
|
2589 //------------------------------build_loop_late--------------------------------
|
|
2590 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping.
|
|
2591 // Second pass finds latest legal placement, and ideal loop placement.
|
|
2592 void PhaseIdealLoop::build_loop_late( VectorSet &visited, Node_List &worklist, Node_Stack &nstack, const PhaseIdealLoop *verify_me ) {
|
|
2593 while (worklist.size() != 0) {
|
|
2594 Node *n = worklist.pop();
|
|
2595 // Only visit once
|
|
2596 if (visited.test_set(n->_idx)) continue;
|
|
2597 uint cnt = n->outcnt();
|
|
2598 uint i = 0;
|
|
2599 while (true) {
|
|
2600 assert( _nodes[n->_idx], "no dead nodes" );
|
|
2601 // Visit all children
|
|
2602 if (i < cnt) {
|
|
2603 Node* use = n->raw_out(i);
|
|
2604 ++i;
|
|
2605 // Check for dead uses. Aggressively prune such junk. It might be
|
|
2606 // dead in the global sense, but still have local uses so I cannot
|
|
2607 // easily call 'remove_dead_node'.
|
|
2608 if( _nodes[use->_idx] != NULL || use->is_top() ) { // Not dead?
|
|
2609 // Due to cycles, we might not hit the same fixed point in the verify
|
|
2610 // pass as we do in the regular pass. Instead, visit such phis as
|
|
2611 // simple uses of the loop head.
|
|
2612 if( use->in(0) && (use->is_CFG() || use->is_Phi()) ) {
|
|
2613 if( !visited.test(use->_idx) )
|
|
2614 worklist.push(use);
|
|
2615 } else if( !visited.test_set(use->_idx) ) {
|
|
2616 nstack.push(n, i); // Save parent and next use's index.
|
|
2617 n = use; // Process all children of current use.
|
|
2618 cnt = use->outcnt();
|
|
2619 i = 0;
|
|
2620 }
|
|
2621 } else {
|
|
2622 // Do not visit around the backedge of loops via data edges.
|
|
2623 // push dead code onto a worklist
|
|
2624 _deadlist.push(use);
|
|
2625 }
|
|
2626 } else {
|
|
2627 // All of n's children have been processed, complete post-processing.
|
|
2628 build_loop_late_post(n, verify_me);
|
|
2629 if (nstack.is_empty()) {
|
|
2630 // Finished all nodes on stack.
|
|
2631 // Process next node on the worklist.
|
|
2632 break;
|
|
2633 }
|
|
2634 // Get saved parent node and next use's index. Visit the rest of uses.
|
|
2635 n = nstack.node();
|
|
2636 cnt = n->outcnt();
|
|
2637 i = nstack.index();
|
|
2638 nstack.pop();
|
|
2639 }
|
|
2640 }
|
|
2641 }
|
|
2642 }
|
|
2643
|
|
2644 //------------------------------build_loop_late_post---------------------------
|
|
2645 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping.
|
|
2646 // Second pass finds latest legal placement, and ideal loop placement.
|
|
2647 void PhaseIdealLoop::build_loop_late_post( Node *n, const PhaseIdealLoop *verify_me ) {
|
|
2648
|
|
2649 if (n->req() == 2 && n->Opcode() == Op_ConvI2L && !C->major_progress()) {
|
|
2650 _igvn._worklist.push(n); // Maybe we'll normalize it, if no more loops.
|
|
2651 }
|
|
2652
|
|
2653 // CFG and pinned nodes already handled
|
|
2654 if( n->in(0) ) {
|
|
2655 if( n->in(0)->is_top() ) return; // Dead?
|
|
2656
|
|
2657 // We'd like +VerifyLoopOptimizations to not believe that Mod's/Loads
|
|
2658 // _must_ be pinned (they have to observe their control edge of course).
|
|
2659 // Unlike Stores (which modify an unallocable resource, the memory
|
|
2660 // state), Mods/Loads can float around. So free them up.
|
|
2661 bool pinned = true;
|
|
2662 switch( n->Opcode() ) {
|
|
2663 case Op_DivI:
|
|
2664 case Op_DivF:
|
|
2665 case Op_DivD:
|
|
2666 case Op_ModI:
|
|
2667 case Op_ModF:
|
|
2668 case Op_ModD:
|
|
2669 case Op_LoadB: // Same with Loads; they can sink
|
|
2670 case Op_LoadC: // during loop optimizations.
|
|
2671 case Op_LoadD:
|
|
2672 case Op_LoadF:
|
|
2673 case Op_LoadI:
|
|
2674 case Op_LoadKlass:
|
|
2675 case Op_LoadL:
|
|
2676 case Op_LoadS:
|
|
2677 case Op_LoadP:
|
|
2678 case Op_LoadRange:
|
|
2679 case Op_LoadD_unaligned:
|
|
2680 case Op_LoadL_unaligned:
|
|
2681 case Op_StrComp: // Does a bunch of load-like effects
|
|
2682 pinned = false;
|
|
2683 }
|
|
2684 if( pinned ) {
|
|
2685 IdealLoopTree *choosen_loop = get_loop(n->is_CFG() ? n : get_ctrl(n));
|
|
2686 if( !choosen_loop->_child ) // Inner loop?
|
|
2687 choosen_loop->_body.push(n); // Collect inner loops
|
|
2688 return;
|
|
2689 }
|
|
2690 } else { // No slot zero
|
|
2691 if( n->is_CFG() ) { // CFG with no slot 0 is dead
|
|
2692 _nodes.map(n->_idx,0); // No block setting, it's globally dead
|
|
2693 return;
|
|
2694 }
|
|
2695 assert(!n->is_CFG() || n->outcnt() == 0, "");
|
|
2696 }
|
|
2697
|
|
2698 // Do I have a "safe range" I can select over?
|
|
2699 Node *early = get_ctrl(n);// Early location already computed
|
|
2700
|
|
2701 // Compute latest point this Node can go
|
|
2702 Node *LCA = get_late_ctrl( n, early );
|
|
2703 // LCA is NULL due to uses being dead
|
|
2704 if( LCA == NULL ) {
|
|
2705 #ifdef ASSERT
|
|
2706 for (DUIterator i1 = n->outs(); n->has_out(i1); i1++) {
|
|
2707 assert( _nodes[n->out(i1)->_idx] == NULL, "all uses must also be dead");
|
|
2708 }
|
|
2709 #endif
|
|
2710 _nodes.map(n->_idx, 0); // This node is useless
|
|
2711 _deadlist.push(n);
|
|
2712 return;
|
|
2713 }
|
|
2714 assert(LCA != NULL && !LCA->is_top(), "no dead nodes");
|
|
2715
|
|
2716 Node *legal = LCA; // Walk 'legal' up the IDOM chain
|
|
2717 Node *least = legal; // Best legal position so far
|
|
2718 while( early != legal ) { // While not at earliest legal
|
|
2719 // Find least loop nesting depth
|
|
2720 legal = idom(legal); // Bump up the IDOM tree
|
|
2721 // Check for lower nesting depth
|
|
2722 if( get_loop(legal)->_nest < get_loop(least)->_nest )
|
|
2723 least = legal;
|
|
2724 }
|
|
2725
|
|
2726 // Try not to place code on a loop entry projection
|
|
2727 // which can inhibit range check elimination.
|
|
2728 if (least != early) {
|
|
2729 Node* ctrl_out = least->unique_ctrl_out();
|
|
2730 if (ctrl_out && ctrl_out->is_CountedLoop() &&
|
|
2731 least == ctrl_out->in(LoopNode::EntryControl)) {
|
|
2732 Node* least_dom = idom(least);
|
|
2733 if (get_loop(least_dom)->is_member(get_loop(least))) {
|
|
2734 least = least_dom;
|
|
2735 }
|
|
2736 }
|
|
2737 }
|
|
2738
|
|
2739 #ifdef ASSERT
|
|
2740 // If verifying, verify that 'verify_me' has a legal location
|
|
2741 // and choose it as our location.
|
|
2742 if( verify_me ) {
|
|
2743 Node *v_ctrl = verify_me->get_ctrl_no_update(n);
|
|
2744 Node *legal = LCA;
|
|
2745 while( early != legal ) { // While not at earliest legal
|
|
2746 if( legal == v_ctrl ) break; // Check for prior good location
|
|
2747 legal = idom(legal) ;// Bump up the IDOM tree
|
|
2748 }
|
|
2749 // Check for prior good location
|
|
2750 if( legal == v_ctrl ) least = legal; // Keep prior if found
|
|
2751 }
|
|
2752 #endif
|
|
2753
|
|
2754 // Assign discovered "here or above" point
|
|
2755 least = find_non_split_ctrl(least);
|
|
2756 set_ctrl(n, least);
|
|
2757
|
|
2758 // Collect inner loop bodies
|
|
2759 IdealLoopTree *choosen_loop = get_loop(least);
|
|
2760 if( !choosen_loop->_child ) // Inner loop?
|
|
2761 choosen_loop->_body.push(n);// Collect inner loops
|
|
2762 }
|
|
2763
|
|
2764 #ifndef PRODUCT
|
|
2765 //------------------------------dump-------------------------------------------
|
|
2766 void PhaseIdealLoop::dump( ) const {
|
|
2767 ResourceMark rm;
|
|
2768 Arena* arena = Thread::current()->resource_area();
|
|
2769 Node_Stack stack(arena, C->unique() >> 2);
|
|
2770 Node_List rpo_list;
|
|
2771 VectorSet visited(arena);
|
|
2772 visited.set(C->top()->_idx);
|
|
2773 rpo( C->root(), stack, visited, rpo_list );
|
|
2774 // Dump root loop indexed by last element in PO order
|
|
2775 dump( _ltree_root, rpo_list.size(), rpo_list );
|
|
2776 }
|
|
2777
|
|
2778 void PhaseIdealLoop::dump( IdealLoopTree *loop, uint idx, Node_List &rpo_list ) const {
|
|
2779
|
|
2780 // Indent by loop nesting depth
|
|
2781 for( uint x = 0; x < loop->_nest; x++ )
|
|
2782 tty->print(" ");
|
|
2783 tty->print_cr("---- Loop N%d-N%d ----", loop->_head->_idx,loop->_tail->_idx);
|
|
2784
|
|
2785 // Now scan for CFG nodes in the same loop
|
|
2786 for( uint j=idx; j > 0; j-- ) {
|
|
2787 Node *n = rpo_list[j-1];
|
|
2788 if( !_nodes[n->_idx] ) // Skip dead nodes
|
|
2789 continue;
|
|
2790 if( get_loop(n) != loop ) { // Wrong loop nest
|
|
2791 if( get_loop(n)->_head == n && // Found nested loop?
|
|
2792 get_loop(n)->_parent == loop )
|
|
2793 dump(get_loop(n),rpo_list.size(),rpo_list); // Print it nested-ly
|
|
2794 continue;
|
|
2795 }
|
|
2796
|
|
2797 // Dump controlling node
|
|
2798 for( uint x = 0; x < loop->_nest; x++ )
|
|
2799 tty->print(" ");
|
|
2800 tty->print("C");
|
|
2801 if( n == C->root() ) {
|
|
2802 n->dump();
|
|
2803 } else {
|
|
2804 Node* cached_idom = idom_no_update(n);
|
|
2805 Node *computed_idom = n->in(0);
|
|
2806 if( n->is_Region() ) {
|
|
2807 computed_idom = compute_idom(n);
|
|
2808 // computed_idom() will return n->in(0) when idom(n) is an IfNode (or
|
|
2809 // any MultiBranch ctrl node), so apply a similar transform to
|
|
2810 // the cached idom returned from idom_no_update.
|
|
2811 cached_idom = find_non_split_ctrl(cached_idom);
|
|
2812 }
|
|
2813 tty->print(" ID:%d",computed_idom->_idx);
|
|
2814 n->dump();
|
|
2815 if( cached_idom != computed_idom ) {
|
|
2816 tty->print_cr("*** BROKEN IDOM! Computed as: %d, cached as: %d",
|
|
2817 computed_idom->_idx, cached_idom->_idx);
|
|
2818 }
|
|
2819 }
|
|
2820 // Dump nodes it controls
|
|
2821 for( uint k = 0; k < _nodes.Size(); k++ ) {
|
|
2822 // (k < C->unique() && get_ctrl(find(k)) == n)
|
|
2823 if (k < C->unique() && _nodes[k] == (Node*)((intptr_t)n + 1)) {
|
|
2824 Node *m = C->root()->find(k);
|
|
2825 if( m && m->outcnt() > 0 ) {
|
|
2826 if (!(has_ctrl(m) && get_ctrl_no_update(m) == n)) {
|
|
2827 tty->print_cr("*** BROKEN CTRL ACCESSOR! _nodes[k] is %p, ctrl is %p",
|
|
2828 _nodes[k], has_ctrl(m) ? get_ctrl_no_update(m) : NULL);
|
|
2829 }
|
|
2830 for( uint j = 0; j < loop->_nest; j++ )
|
|
2831 tty->print(" ");
|
|
2832 tty->print(" ");
|
|
2833 m->dump();
|
|
2834 }
|
|
2835 }
|
|
2836 }
|
|
2837 }
|
|
2838 }
|
|
2839
|
|
2840 // Collect a R-P-O for the whole CFG.
|
|
2841 // Result list is in post-order (scan backwards for RPO)
|
|
2842 void PhaseIdealLoop::rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const {
|
|
2843 stk.push(start, 0);
|
|
2844 visited.set(start->_idx);
|
|
2845
|
|
2846 while (stk.is_nonempty()) {
|
|
2847 Node* m = stk.node();
|
|
2848 uint idx = stk.index();
|
|
2849 if (idx < m->outcnt()) {
|
|
2850 stk.set_index(idx + 1);
|
|
2851 Node* n = m->raw_out(idx);
|
|
2852 if (n->is_CFG() && !visited.test_set(n->_idx)) {
|
|
2853 stk.push(n, 0);
|
|
2854 }
|
|
2855 } else {
|
|
2856 rpo_list.push(m);
|
|
2857 stk.pop();
|
|
2858 }
|
|
2859 }
|
|
2860 }
|
|
2861 #endif
|
|
2862
|
|
2863
|
|
2864 //=============================================================================
|
|
2865 //------------------------------LoopTreeIterator-----------------------------------
|
|
2866
|
|
2867 // Advance to next loop tree using a preorder, left-to-right traversal.
|
|
2868 void LoopTreeIterator::next() {
|
|
2869 assert(!done(), "must not be done.");
|
|
2870 if (_curnt->_child != NULL) {
|
|
2871 _curnt = _curnt->_child;
|
|
2872 } else if (_curnt->_next != NULL) {
|
|
2873 _curnt = _curnt->_next;
|
|
2874 } else {
|
|
2875 while (_curnt != _root && _curnt->_next == NULL) {
|
|
2876 _curnt = _curnt->_parent;
|
|
2877 }
|
|
2878 if (_curnt == _root) {
|
|
2879 _curnt = NULL;
|
|
2880 assert(done(), "must be done.");
|
|
2881 } else {
|
|
2882 assert(_curnt->_next != NULL, "must be more to do");
|
|
2883 _curnt = _curnt->_next;
|
|
2884 }
|
|
2885 }
|
|
2886 }
|