1 /* 2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "compiler/compileLog.hpp" 27 #include "memory/allocation.inline.hpp" 28 #include "opto/addnode.hpp" 29 #include "opto/callnode.hpp" 30 #include "opto/cfgnode.hpp" 31 #include "opto/loopnode.hpp" 32 #include "opto/matcher.hpp" 33 #include "opto/movenode.hpp" 34 #include "opto/mulnode.hpp" 35 #include "opto/opcodes.hpp" 36 #include "opto/phaseX.hpp" 37 #include "opto/subnode.hpp" 38 #include "runtime/sharedRuntime.hpp" 39 40 // Portions of code courtesy of Clifford Click 41 42 // Optimization - Graph Style 43 44 #include "math.h" 45 46 //============================================================================= 47 //------------------------------Identity--------------------------------------- 48 // If right input is a constant 0, return the left input. 49 Node* SubNode::Identity(PhaseGVN* phase) { 50 assert(in(1) != this, "Must already have called Value"); 51 assert(in(2) != this, "Must already have called Value"); 52 53 // Remove double negation 54 const Type *zero = add_id(); 55 if( phase->type( in(1) )->higher_equal( zero ) && 56 in(2)->Opcode() == Opcode() && 57 phase->type( in(2)->in(1) )->higher_equal( zero ) ) { 58 return in(2)->in(2); 59 } 60 61 // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y 62 if( in(1)->Opcode() == Opcodes::Op_AddI ) { 63 if( phase->eqv(in(1)->in(2),in(2)) ) 64 return in(1)->in(1); 65 if (phase->eqv(in(1)->in(1),in(2))) 66 return in(1)->in(2); 67 68 // Also catch: "(X + Opaque2(Y)) - Y". In this case, 'Y' is a loop-varying 69 // trip counter and X is likely to be loop-invariant (that's how O2 Nodes 70 // are originally used, although the optimizer sometimes jiggers things). 71 // This folding through an O2 removes a loop-exit use of a loop-varying 72 // value and generally lowers register pressure in and around the loop. 73 if( in(1)->in(2)->Opcode() == Opcodes::Op_Opaque2 && 74 phase->eqv(in(1)->in(2)->in(1),in(2)) ) 75 return in(1)->in(1); 76 } 77 78 return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this; 79 } 80 81 //------------------------------Value------------------------------------------ 82 // A subtract node differences it's two inputs. 83 const Type* SubNode::Value_common(PhaseTransform *phase) const { 84 const Node* in1 = in(1); 85 const Node* in2 = in(2); 86 // Either input is TOP ==> the result is TOP 87 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 88 if( t1 == Type::TOP ) return Type::TOP; 89 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 90 if( t2 == Type::TOP ) return Type::TOP; 91 92 // Not correct for SubFnode and AddFNode (must check for infinity) 93 // Equal? Subtract is zero 94 if (in1->eqv_uncast(in2)) return add_id(); 95 96 // Either input is BOTTOM ==> the result is the local BOTTOM 97 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM ) 98 return bottom_type(); 99 100 return NULL; 101 } 102 103 const Type* SubNode::Value(PhaseGVN* phase) const { 104 const Type* t = Value_common(phase); 105 if (t != NULL) { 106 return t; 107 } 108 const Type* t1 = phase->type(in(1)); 109 const Type* t2 = phase->type(in(2)); 110 return sub(t1,t2); // Local flavor of type subtraction 111 112 } 113 114 //============================================================================= 115 116 //------------------------------Helper function-------------------------------- 117 static bool ok_to_convert(Node* inc, Node* iv) { 118 // Do not collapse (x+c0)-y if "+" is a loop increment, because the 119 // "-" is loop invariant and collapsing extends the live-range of "x" 120 // to overlap with the "+", forcing another register to be used in 121 // the loop. 122 // This test will be clearer with '&&' (apply DeMorgan's rule) 123 // but I like the early cutouts that happen here. 124 const PhiNode *phi; 125 if( ( !inc->in(1)->is_Phi() || 126 !(phi=inc->in(1)->as_Phi()) || 127 phi->is_copy() || 128 !phi->region()->is_CountedLoop() || 129 inc != phi->region()->as_CountedLoop()->incr() ) 130 && 131 // Do not collapse (x+c0)-iv if "iv" is a loop induction variable, 132 // because "x" maybe invariant. 133 ( !iv->is_loop_iv() ) 134 ) { 135 return true; 136 } else { 137 return false; 138 } 139 } 140 //------------------------------Ideal------------------------------------------ 141 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){ 142 Node *in1 = in(1); 143 Node *in2 = in(2); 144 Opcodes op1 = in1->Opcode(); 145 Opcodes op2 = in2->Opcode(); 146 147 #ifdef ASSERT 148 // Check for dead loop 149 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 150 ( op1 == Opcodes::Op_AddI || op1 == Opcodes::Op_SubI ) && 151 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 152 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 153 assert(false, "dead loop in SubINode::Ideal"); 154 #endif 155 156 const Type *t2 = phase->type( in2 ); 157 if( t2 == Type::TOP ) return NULL; 158 // Convert "x-c0" into "x+ -c0". 159 if( t2->base() == Type::Int ){ // Might be bottom or top... 160 const TypeInt *i = t2->is_int(); 161 if( i->is_con() ) 162 return new AddINode(in1, phase->intcon(-i->get_con())); 163 } 164 165 // Convert "(x+c0) - y" into (x-y) + c0" 166 // Do not collapse (x+c0)-y if "+" is a loop increment or 167 // if "y" is a loop induction variable. 168 if( op1 == Opcodes::Op_AddI && ok_to_convert(in1, in2) ) { 169 const Type *tadd = phase->type( in1->in(2) ); 170 if( tadd->singleton() && tadd != Type::TOP ) { 171 Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 )); 172 return new AddINode( sub2, in1->in(2) ); 173 } 174 } 175 176 177 // Convert "x - (y+c0)" into "(x-y) - c0" 178 // Need the same check as in above optimization but reversed. 179 if (op2 == Opcodes::Op_AddI && ok_to_convert(in2, in1)) { 180 Node* in21 = in2->in(1); 181 Node* in22 = in2->in(2); 182 const TypeInt* tcon = phase->type(in22)->isa_int(); 183 if (tcon != NULL && tcon->is_con()) { 184 Node* sub2 = phase->transform( new SubINode(in1, in21) ); 185 Node* neg_c0 = phase->intcon(- tcon->get_con()); 186 return new AddINode(sub2, neg_c0); 187 } 188 } 189 190 const Type *t1 = phase->type( in1 ); 191 if( t1 == Type::TOP ) return NULL; 192 193 #ifdef ASSERT 194 // Check for dead loop 195 if( ( op2 == Opcodes::Op_AddI || op2 == Opcodes::Op_SubI ) && 196 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 197 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 198 assert(false, "dead loop in SubINode::Ideal"); 199 #endif 200 201 // Convert "x - (x+y)" into "-y" 202 if( op2 == Opcodes::Op_AddI && 203 phase->eqv( in1, in2->in(1) ) ) 204 return new SubINode( phase->intcon(0),in2->in(2)); 205 // Convert "(x-y) - x" into "-y" 206 if( op1 == Opcodes::Op_SubI && 207 phase->eqv( in1->in(1), in2 ) ) 208 return new SubINode( phase->intcon(0),in1->in(2)); 209 // Convert "x - (y+x)" into "-y" 210 if( op2 == Opcodes::Op_AddI && 211 phase->eqv( in1, in2->in(2) ) ) 212 return new SubINode( phase->intcon(0),in2->in(1)); 213 214 // Convert "0 - (x-y)" into "y-x" 215 if( t1 == TypeInt::ZERO && op2 == Opcodes::Op_SubI ) 216 return new SubINode( in2->in(2), in2->in(1) ); 217 218 // Convert "0 - (x+con)" into "-con-x" 219 jint con; 220 if( t1 == TypeInt::ZERO && op2 == Opcodes::Op_AddI && 221 (con = in2->in(2)->find_int_con(0)) != 0 ) 222 return new SubINode( phase->intcon(-con), in2->in(1) ); 223 224 // Convert "(X+A) - (X+B)" into "A - B" 225 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(1) == in2->in(1) ) 226 return new SubINode( in1->in(2), in2->in(2) ); 227 228 // Convert "(A+X) - (B+X)" into "A - B" 229 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(2) ) 230 return new SubINode( in1->in(1), in2->in(1) ); 231 232 // Convert "(A+X) - (X+B)" into "A - B" 233 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(1) ) 234 return new SubINode( in1->in(1), in2->in(2) ); 235 236 // Convert "(X+A) - (B+X)" into "A - B" 237 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(1) == in2->in(2) ) 238 return new SubINode( in1->in(2), in2->in(1) ); 239 240 // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally 241 // nicer to optimize than subtract. 242 if( op2 == Opcodes::Op_SubI && in2->outcnt() == 1) { 243 Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) ); 244 return new SubINode( add1, in2->in(1) ); 245 } 246 247 return NULL; 248 } 249 250 //------------------------------sub-------------------------------------------- 251 // A subtract node differences it's two inputs. 252 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const { 253 const TypeInt *r0 = t1->is_int(); // Handy access 254 const TypeInt *r1 = t2->is_int(); 255 int32_t lo = java_subtract(r0->_lo, r1->_hi); 256 int32_t hi = java_subtract(r0->_hi, r1->_lo); 257 258 // We next check for 32-bit overflow. 259 // If that happens, we just assume all integers are possible. 260 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 261 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 262 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR 263 ((r0->_hi ^ hi) >= 0)) ) // hi results have same signs 264 return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen)); 265 else // Overflow; assume all integers 266 return TypeInt::INT; 267 } 268 269 //============================================================================= 270 //------------------------------Ideal------------------------------------------ 271 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 272 Node *in1 = in(1); 273 Node *in2 = in(2); 274 Opcodes op1 = in1->Opcode(); 275 Opcodes op2 = in2->Opcode(); 276 277 #ifdef ASSERT 278 // Check for dead loop 279 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 280 ( op1 == Opcodes::Op_AddL || op1 == Opcodes::Op_SubL ) && 281 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 282 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 283 assert(false, "dead loop in SubLNode::Ideal"); 284 #endif 285 286 if( phase->type( in2 ) == Type::TOP ) return NULL; 287 const TypeLong *i = phase->type( in2 )->isa_long(); 288 // Convert "x-c0" into "x+ -c0". 289 if( i && // Might be bottom or top... 290 i->is_con() ) 291 return new AddLNode(in1, phase->longcon(-i->get_con())); 292 293 // Convert "(x+c0) - y" into (x-y) + c0" 294 // Do not collapse (x+c0)-y if "+" is a loop increment or 295 // if "y" is a loop induction variable. 296 if( op1 == Opcodes::Op_AddL && ok_to_convert(in1, in2) ) { 297 Node *in11 = in1->in(1); 298 const Type *tadd = phase->type( in1->in(2) ); 299 if( tadd->singleton() && tadd != Type::TOP ) { 300 Node *sub2 = phase->transform( new SubLNode( in11, in2 )); 301 return new AddLNode( sub2, in1->in(2) ); 302 } 303 } 304 305 // Convert "x - (y+c0)" into "(x-y) - c0" 306 // Need the same check as in above optimization but reversed. 307 if (op2 == Opcodes::Op_AddL && ok_to_convert(in2, in1)) { 308 Node* in21 = in2->in(1); 309 Node* in22 = in2->in(2); 310 const TypeLong* tcon = phase->type(in22)->isa_long(); 311 if (tcon != NULL && tcon->is_con()) { 312 Node* sub2 = phase->transform( new SubLNode(in1, in21) ); 313 Node* neg_c0 = phase->longcon(- tcon->get_con()); 314 return new AddLNode(sub2, neg_c0); 315 } 316 } 317 318 const Type *t1 = phase->type( in1 ); 319 if( t1 == Type::TOP ) return NULL; 320 321 #ifdef ASSERT 322 // Check for dead loop 323 if( ( op2 == Opcodes::Op_AddL || op2 == Opcodes::Op_SubL ) && 324 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 325 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 326 assert(false, "dead loop in SubLNode::Ideal"); 327 #endif 328 329 // Convert "x - (x+y)" into "-y" 330 if( op2 == Opcodes::Op_AddL && 331 phase->eqv( in1, in2->in(1) ) ) 332 return new SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2)); 333 // Convert "x - (y+x)" into "-y" 334 if( op2 == Opcodes::Op_AddL && 335 phase->eqv( in1, in2->in(2) ) ) 336 return new SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1)); 337 338 // Convert "0 - (x-y)" into "y-x" 339 if( phase->type( in1 ) == TypeLong::ZERO && op2 == Opcodes::Op_SubL ) 340 return new SubLNode( in2->in(2), in2->in(1) ); 341 342 // Convert "(X+A) - (X+B)" into "A - B" 343 if( op1 == Opcodes::Op_AddL && op2 == Opcodes::Op_AddL && in1->in(1) == in2->in(1) ) 344 return new SubLNode( in1->in(2), in2->in(2) ); 345 346 // Convert "(A+X) - (B+X)" into "A - B" 347 if( op1 == Opcodes::Op_AddL && op2 == Opcodes::Op_AddL && in1->in(2) == in2->in(2) ) 348 return new SubLNode( in1->in(1), in2->in(1) ); 349 350 // Convert "A-(B-C)" into (A+C)-B" 351 if( op2 == Opcodes::Op_SubL && in2->outcnt() == 1) { 352 Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) ); 353 return new SubLNode( add1, in2->in(1) ); 354 } 355 356 return NULL; 357 } 358 359 //------------------------------sub-------------------------------------------- 360 // A subtract node differences it's two inputs. 361 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const { 362 const TypeLong *r0 = t1->is_long(); // Handy access 363 const TypeLong *r1 = t2->is_long(); 364 jlong lo = java_subtract(r0->_lo, r1->_hi); 365 jlong hi = java_subtract(r0->_hi, r1->_lo); 366 367 // We next check for 32-bit overflow. 368 // If that happens, we just assume all integers are possible. 369 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 370 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 371 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR 372 ((r0->_hi ^ hi) >= 0)) ) // hi results have same signs 373 return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen)); 374 else // Overflow; assume all integers 375 return TypeLong::LONG; 376 } 377 378 //============================================================================= 379 //------------------------------Value------------------------------------------ 380 // A subtract node differences its two inputs. 381 const Type* SubFPNode::Value(PhaseGVN* phase) const { 382 const Node* in1 = in(1); 383 const Node* in2 = in(2); 384 // Either input is TOP ==> the result is TOP 385 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 386 if( t1 == Type::TOP ) return Type::TOP; 387 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 388 if( t2 == Type::TOP ) return Type::TOP; 389 390 // if both operands are infinity of same sign, the result is NaN; do 391 // not replace with zero 392 if( (t1->is_finite() && t2->is_finite()) ) { 393 if( phase->eqv(in1, in2) ) return add_id(); 394 } 395 396 // Either input is BOTTOM ==> the result is the local BOTTOM 397 const Type *bot = bottom_type(); 398 if( (t1 == bot) || (t2 == bot) || 399 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 400 return bot; 401 402 return sub(t1,t2); // Local flavor of type subtraction 403 } 404 405 406 //============================================================================= 407 //------------------------------Ideal------------------------------------------ 408 Node *SubFNode::Ideal(PhaseGVN *phase, bool can_reshape) { 409 const Type *t2 = phase->type( in(2) ); 410 // Convert "x-c0" into "x+ -c0". 411 if( t2->base() == Type::FloatCon ) { // Might be bottom or top... 412 // return new (phase->C, 3) AddFNode(in(1), phase->makecon( TypeF::make(-t2->getf()) ) ); 413 } 414 415 // Not associative because of boundary conditions (infinity) 416 if( IdealizedNumerics && !phase->C->method()->is_strict() ) { 417 // Convert "x - (x+y)" into "-y" 418 if( in(2)->is_Add() && 419 phase->eqv(in(1),in(2)->in(1) ) ) 420 return new SubFNode( phase->makecon(TypeF::ZERO),in(2)->in(2)); 421 } 422 423 // Cannot replace 0.0-X with -X because a 'fsub' bytecode computes 424 // 0.0-0.0 as +0.0, while a 'fneg' bytecode computes -0.0. 425 //if( phase->type(in(1)) == TypeF::ZERO ) 426 //return new (phase->C, 2) NegFNode(in(2)); 427 428 return NULL; 429 } 430 431 //------------------------------sub-------------------------------------------- 432 // A subtract node differences its two inputs. 433 const Type *SubFNode::sub( const Type *t1, const Type *t2 ) const { 434 // no folding if one of operands is infinity or NaN, do not do constant folding 435 if( g_isfinite(t1->getf()) && g_isfinite(t2->getf()) ) { 436 return TypeF::make( t1->getf() - t2->getf() ); 437 } 438 else if( g_isnan(t1->getf()) ) { 439 return t1; 440 } 441 else if( g_isnan(t2->getf()) ) { 442 return t2; 443 } 444 else { 445 return Type::FLOAT; 446 } 447 } 448 449 //============================================================================= 450 //------------------------------Ideal------------------------------------------ 451 Node *SubDNode::Ideal(PhaseGVN *phase, bool can_reshape){ 452 const Type *t2 = phase->type( in(2) ); 453 // Convert "x-c0" into "x+ -c0". 454 if( t2->base() == Type::DoubleCon ) { // Might be bottom or top... 455 // return new (phase->C, 3) AddDNode(in(1), phase->makecon( TypeD::make(-t2->getd()) ) ); 456 } 457 458 // Not associative because of boundary conditions (infinity) 459 if( IdealizedNumerics && !phase->C->method()->is_strict() ) { 460 // Convert "x - (x+y)" into "-y" 461 if( in(2)->is_Add() && 462 phase->eqv(in(1),in(2)->in(1) ) ) 463 return new SubDNode( phase->makecon(TypeD::ZERO),in(2)->in(2)); 464 } 465 466 // Cannot replace 0.0-X with -X because a 'dsub' bytecode computes 467 // 0.0-0.0 as +0.0, while a 'dneg' bytecode computes -0.0. 468 //if( phase->type(in(1)) == TypeD::ZERO ) 469 //return new (phase->C, 2) NegDNode(in(2)); 470 471 return NULL; 472 } 473 474 //------------------------------sub-------------------------------------------- 475 // A subtract node differences its two inputs. 476 const Type *SubDNode::sub( const Type *t1, const Type *t2 ) const { 477 // no folding if one of operands is infinity or NaN, do not do constant folding 478 if( g_isfinite(t1->getd()) && g_isfinite(t2->getd()) ) { 479 return TypeD::make( t1->getd() - t2->getd() ); 480 } 481 else if( g_isnan(t1->getd()) ) { 482 return t1; 483 } 484 else if( g_isnan(t2->getd()) ) { 485 return t2; 486 } 487 else { 488 return Type::DOUBLE; 489 } 490 } 491 492 //============================================================================= 493 //------------------------------Idealize--------------------------------------- 494 // Unlike SubNodes, compare must still flatten return value to the 495 // range -1, 0, 1. 496 // And optimizations like those for (X + Y) - X fail if overflow happens. 497 Node* CmpNode::Identity(PhaseGVN* phase) { 498 return this; 499 } 500 501 #ifndef PRODUCT 502 //----------------------------related------------------------------------------ 503 // Related nodes of comparison nodes include all data inputs (until hitting a 504 // control boundary) as well as all outputs until and including control nodes 505 // as well as their projections. In compact mode, data inputs till depth 1 and 506 // all outputs till depth 1 are considered. 507 void CmpNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 508 if (compact) { 509 this->collect_nodes(in_rel, 1, false, true); 510 this->collect_nodes(out_rel, -1, false, false); 511 } else { 512 this->collect_nodes_in_all_data(in_rel, false); 513 this->collect_nodes_out_all_ctrl_boundary(out_rel); 514 // Now, find all control nodes in out_rel, and include their projections 515 // and projection targets (if any) in the result. 516 GrowableArray<Node*> proj(Compile::current()->unique()); 517 for (GrowableArrayIterator<Node*> it = out_rel->begin(); it != out_rel->end(); ++it) { 518 Node* n = *it; 519 if (n->is_CFG() && !n->is_Proj()) { 520 // Assume projections and projection targets are found at levels 1 and 2. 521 n->collect_nodes(&proj, -2, false, false); 522 for (GrowableArrayIterator<Node*> p = proj.begin(); p != proj.end(); ++p) { 523 out_rel->append_if_missing(*p); 524 } 525 proj.clear(); 526 } 527 } 528 } 529 } 530 #endif 531 532 //============================================================================= 533 //------------------------------cmp-------------------------------------------- 534 // Simplify a CmpI (compare 2 integers) node, based on local information. 535 // If both inputs are constants, compare them. 536 const Type *CmpINode::sub( const Type *t1, const Type *t2 ) const { 537 const TypeInt *r0 = t1->is_int(); // Handy access 538 const TypeInt *r1 = t2->is_int(); 539 540 if( r0->_hi < r1->_lo ) // Range is always low? 541 return TypeInt::CC_LT; 542 else if( r0->_lo > r1->_hi ) // Range is always high? 543 return TypeInt::CC_GT; 544 545 else if( r0->is_con() && r1->is_con() ) { // comparing constants? 546 assert(r0->get_con() == r1->get_con(), "must be equal"); 547 return TypeInt::CC_EQ; // Equal results. 548 } else if( r0->_hi == r1->_lo ) // Range is never high? 549 return TypeInt::CC_LE; 550 else if( r0->_lo == r1->_hi ) // Range is never low? 551 return TypeInt::CC_GE; 552 return TypeInt::CC; // else use worst case results 553 } 554 555 // Simplify a CmpU (compare 2 integers) node, based on local information. 556 // If both inputs are constants, compare them. 557 const Type *CmpUNode::sub( const Type *t1, const Type *t2 ) const { 558 assert(!t1->isa_ptr(), "obsolete usage of CmpU"); 559 560 // comparing two unsigned ints 561 const TypeInt *r0 = t1->is_int(); // Handy access 562 const TypeInt *r1 = t2->is_int(); 563 564 // Current installed version 565 // Compare ranges for non-overlap 566 juint lo0 = r0->_lo; 567 juint hi0 = r0->_hi; 568 juint lo1 = r1->_lo; 569 juint hi1 = r1->_hi; 570 571 // If either one has both negative and positive values, 572 // it therefore contains both 0 and -1, and since [0..-1] is the 573 // full unsigned range, the type must act as an unsigned bottom. 574 bool bot0 = ((jint)(lo0 ^ hi0) < 0); 575 bool bot1 = ((jint)(lo1 ^ hi1) < 0); 576 577 if (bot0 || bot1) { 578 // All unsigned values are LE -1 and GE 0. 579 if (lo0 == 0 && hi0 == 0) { 580 return TypeInt::CC_LE; // 0 <= bot 581 } else if ((jint)lo0 == -1 && (jint)hi0 == -1) { 582 return TypeInt::CC_GE; // -1 >= bot 583 } else if (lo1 == 0 && hi1 == 0) { 584 return TypeInt::CC_GE; // bot >= 0 585 } else if ((jint)lo1 == -1 && (jint)hi1 == -1) { 586 return TypeInt::CC_LE; // bot <= -1 587 } 588 } else { 589 // We can use ranges of the form [lo..hi] if signs are the same. 590 assert(lo0 <= hi0 && lo1 <= hi1, "unsigned ranges are valid"); 591 // results are reversed, '-' > '+' for unsigned compare 592 if (hi0 < lo1) { 593 return TypeInt::CC_LT; // smaller 594 } else if (lo0 > hi1) { 595 return TypeInt::CC_GT; // greater 596 } else if (hi0 == lo1 && lo0 == hi1) { 597 return TypeInt::CC_EQ; // Equal results 598 } else if (lo0 >= hi1) { 599 return TypeInt::CC_GE; 600 } else if (hi0 <= lo1) { 601 // Check for special case in Hashtable::get. (See below.) 602 if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check()) 603 return TypeInt::CC_LT; 604 return TypeInt::CC_LE; 605 } 606 } 607 // Check for special case in Hashtable::get - the hash index is 608 // mod'ed to the table size so the following range check is useless. 609 // Check for: (X Mod Y) CmpU Y, where the mod result and Y both have 610 // to be positive. 611 // (This is a gross hack, since the sub method never 612 // looks at the structure of the node in any other case.) 613 if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check()) 614 return TypeInt::CC_LT; 615 return TypeInt::CC; // else use worst case results 616 } 617 618 const Type* CmpUNode::Value(PhaseGVN* phase) const { 619 const Type* t = SubNode::Value_common(phase); 620 if (t != NULL) { 621 return t; 622 } 623 const Node* in1 = in(1); 624 const Node* in2 = in(2); 625 const Type* t1 = phase->type(in1); 626 const Type* t2 = phase->type(in2); 627 assert(t1->isa_int(), "CmpU has only Int type inputs"); 628 if (t2 == TypeInt::INT) { // Compare to bottom? 629 return bottom_type(); 630 } 631 Opcodes in1_op = in1->Opcode(); 632 if (in1_op == Opcodes::Op_AddI || in1_op == Opcodes::Op_SubI) { 633 // The problem rise when result of AddI(SubI) may overflow 634 // signed integer value. Let say the input type is 635 // [256, maxint] then +128 will create 2 ranges due to 636 // overflow: [minint, minint+127] and [384, maxint]. 637 // But C2 type system keep only 1 type range and as result 638 // it use general [minint, maxint] for this case which we 639 // can't optimize. 640 // 641 // Make 2 separate type ranges based on types of AddI(SubI) inputs 642 // and compare results of their compare. If results are the same 643 // CmpU node can be optimized. 644 const Node* in11 = in1->in(1); 645 const Node* in12 = in1->in(2); 646 const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11); 647 const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12); 648 // Skip cases when input types are top or bottom. 649 if ((t11 != Type::TOP) && (t11 != TypeInt::INT) && 650 (t12 != Type::TOP) && (t12 != TypeInt::INT)) { 651 const TypeInt *r0 = t11->is_int(); 652 const TypeInt *r1 = t12->is_int(); 653 jlong lo_r0 = r0->_lo; 654 jlong hi_r0 = r0->_hi; 655 jlong lo_r1 = r1->_lo; 656 jlong hi_r1 = r1->_hi; 657 if (in1_op == Opcodes::Op_SubI) { 658 jlong tmp = hi_r1; 659 hi_r1 = -lo_r1; 660 lo_r1 = -tmp; 661 // Note, for substructing [minint,x] type range 662 // long arithmetic provides correct overflow answer. 663 // The confusion come from the fact that in 32-bit 664 // -minint == minint but in 64-bit -minint == maxint+1. 665 } 666 jlong lo_long = lo_r0 + lo_r1; 667 jlong hi_long = hi_r0 + hi_r1; 668 int lo_tr1 = min_jint; 669 int hi_tr1 = (int)hi_long; 670 int lo_tr2 = (int)lo_long; 671 int hi_tr2 = max_jint; 672 bool underflow = lo_long != (jlong)lo_tr2; 673 bool overflow = hi_long != (jlong)hi_tr1; 674 // Use sub(t1, t2) when there is no overflow (one type range) 675 // or when both overflow and underflow (too complex). 676 if ((underflow != overflow) && (hi_tr1 < lo_tr2)) { 677 // Overflow only on one boundary, compare 2 separate type ranges. 678 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 679 const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w); 680 const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w); 681 const Type* cmp1 = sub(tr1, t2); 682 const Type* cmp2 = sub(tr2, t2); 683 if (cmp1 == cmp2) { 684 return cmp1; // Hit! 685 } 686 } 687 } 688 } 689 690 return sub(t1, t2); // Local flavor of type subtraction 691 } 692 693 bool CmpUNode::is_index_range_check() const { 694 // Check for the "(X ModI Y) CmpU Y" shape 695 return (in(1)->Opcode() == Opcodes::Op_ModI && 696 in(1)->in(2)->eqv_uncast(in(2))); 697 } 698 699 //------------------------------Idealize--------------------------------------- 700 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) { 701 if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) { 702 switch (in(1)->Opcode()) { 703 case Opcodes::Op_CmpL3: // Collapse a CmpL3/CmpI into a CmpL 704 return new CmpLNode(in(1)->in(1),in(1)->in(2)); 705 case Opcodes::Op_CmpF3: // Collapse a CmpF3/CmpI into a CmpF 706 return new CmpFNode(in(1)->in(1),in(1)->in(2)); 707 case Opcodes::Op_CmpD3: // Collapse a CmpD3/CmpI into a CmpD 708 return new CmpDNode(in(1)->in(1),in(1)->in(2)); 709 //case Op_SubI: 710 // If (x - y) cannot overflow, then ((x - y) <?> 0) 711 // can be turned into (x <?> y). 712 // This is handled (with more general cases) by Ideal_sub_algebra. 713 } 714 } 715 return NULL; // No change 716 } 717 718 719 //============================================================================= 720 // Simplify a CmpL (compare 2 longs ) node, based on local information. 721 // If both inputs are constants, compare them. 722 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const { 723 const TypeLong *r0 = t1->is_long(); // Handy access 724 const TypeLong *r1 = t2->is_long(); 725 726 if( r0->_hi < r1->_lo ) // Range is always low? 727 return TypeInt::CC_LT; 728 else if( r0->_lo > r1->_hi ) // Range is always high? 729 return TypeInt::CC_GT; 730 731 else if( r0->is_con() && r1->is_con() ) { // comparing constants? 732 assert(r0->get_con() == r1->get_con(), "must be equal"); 733 return TypeInt::CC_EQ; // Equal results. 734 } else if( r0->_hi == r1->_lo ) // Range is never high? 735 return TypeInt::CC_LE; 736 else if( r0->_lo == r1->_hi ) // Range is never low? 737 return TypeInt::CC_GE; 738 return TypeInt::CC; // else use worst case results 739 } 740 741 //============================================================================= 742 //------------------------------sub-------------------------------------------- 743 // Simplify an CmpP (compare 2 pointers) node, based on local information. 744 // If both inputs are constants, compare them. 745 const Type *CmpPNode::sub( const Type *t1, const Type *t2 ) const { 746 const TypePtr *r0 = t1->is_ptr(); // Handy access 747 const TypePtr *r1 = t2->is_ptr(); 748 749 // Undefined inputs makes for an undefined result 750 if( TypePtr::above_centerline(r0->_ptr) || 751 TypePtr::above_centerline(r1->_ptr) ) 752 return Type::TOP; 753 754 if (r0 == r1 && r0->singleton()) { 755 // Equal pointer constants (klasses, nulls, etc.) 756 return TypeInt::CC_EQ; 757 } 758 759 // See if it is 2 unrelated classes. 760 const TypeOopPtr* p0 = r0->isa_oopptr(); 761 const TypeOopPtr* p1 = r1->isa_oopptr(); 762 if (p0 && p1) { 763 Node* in1 = in(1)->uncast(); 764 Node* in2 = in(2)->uncast(); 765 AllocateNode* alloc1 = AllocateNode::Ideal_allocation(in1, NULL); 766 AllocateNode* alloc2 = AllocateNode::Ideal_allocation(in2, NULL); 767 if (MemNode::detect_ptr_independence(in1, alloc1, in2, alloc2, NULL)) { 768 return TypeInt::CC_GT; // different pointers 769 } 770 ciKlass* klass0 = p0->klass(); 771 bool xklass0 = p0->klass_is_exact(); 772 ciKlass* klass1 = p1->klass(); 773 bool xklass1 = p1->klass_is_exact(); 774 int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0); 775 if (klass0 && klass1 && 776 kps != 1 && // both or neither are klass pointers 777 klass0->is_loaded() && !klass0->is_interface() && // do not trust interfaces 778 klass1->is_loaded() && !klass1->is_interface() && 779 (!klass0->is_obj_array_klass() || 780 !klass0->as_obj_array_klass()->base_element_klass()->is_interface()) && 781 (!klass1->is_obj_array_klass() || 782 !klass1->as_obj_array_klass()->base_element_klass()->is_interface())) { 783 bool unrelated_classes = false; 784 // See if neither subclasses the other, or if the class on top 785 // is precise. In either of these cases, the compare is known 786 // to fail if at least one of the pointers is provably not null. 787 if (klass0->equals(klass1)) { // if types are unequal but klasses are equal 788 // Do nothing; we know nothing for imprecise types 789 } else if (klass0->is_subtype_of(klass1)) { 790 // If klass1's type is PRECISE, then classes are unrelated. 791 unrelated_classes = xklass1; 792 } else if (klass1->is_subtype_of(klass0)) { 793 // If klass0's type is PRECISE, then classes are unrelated. 794 unrelated_classes = xklass0; 795 } else { // Neither subtypes the other 796 unrelated_classes = true; 797 } 798 if (unrelated_classes) { 799 // The oops classes are known to be unrelated. If the joined PTRs of 800 // two oops is not Null and not Bottom, then we are sure that one 801 // of the two oops is non-null, and the comparison will always fail. 802 TypePtr::PTR jp = r0->join_ptr(r1->_ptr); 803 if (jp != TypePtr::Null && jp != TypePtr::BotPTR) { 804 return TypeInt::CC_GT; 805 } 806 } 807 } 808 } 809 810 // Known constants can be compared exactly 811 // Null can be distinguished from any NotNull pointers 812 // Unknown inputs makes an unknown result 813 if( r0->singleton() ) { 814 intptr_t bits0 = r0->get_con(); 815 if( r1->singleton() ) 816 return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT; 817 return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC; 818 } else if( r1->singleton() ) { 819 intptr_t bits1 = r1->get_con(); 820 return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC; 821 } else 822 return TypeInt::CC; 823 } 824 825 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) { 826 // Return the klass node for 827 // LoadP(AddP(foo:Klass, #java_mirror)) 828 // or NULL if not matching. 829 if (n->Opcode() != Opcodes::Op_LoadP) return NULL; 830 831 const TypeInstPtr* tp = phase->type(n)->isa_instptr(); 832 if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL; 833 834 Node* adr = n->in(MemNode::Address); 835 intptr_t off = 0; 836 Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off); 837 if (k == NULL) return NULL; 838 const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr(); 839 if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL; 840 841 // We've found the klass node of a Java mirror load. 842 return k; 843 } 844 845 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) { 846 // for ConP(Foo.class) return ConP(Foo.klass) 847 // otherwise return NULL 848 if (!n->is_Con()) return NULL; 849 850 const TypeInstPtr* tp = phase->type(n)->isa_instptr(); 851 if (!tp) return NULL; 852 853 ciType* mirror_type = tp->java_mirror_type(); 854 // TypeInstPtr::java_mirror_type() returns non-NULL for compile- 855 // time Class constants only. 856 if (!mirror_type) return NULL; 857 858 // x.getClass() == int.class can never be true (for all primitive types) 859 // Return a ConP(NULL) node for this case. 860 if (mirror_type->is_classless()) { 861 return phase->makecon(TypePtr::NULL_PTR); 862 } 863 864 // return the ConP(Foo.klass) 865 assert(mirror_type->is_klass(), "mirror_type should represent a Klass*"); 866 return phase->makecon(TypeKlassPtr::make(mirror_type->as_klass())); 867 } 868 869 //------------------------------Ideal------------------------------------------ 870 // Normalize comparisons between Java mirror loads to compare the klass instead. 871 // 872 // Also check for the case of comparing an unknown klass loaded from the primary 873 // super-type array vs a known klass with no subtypes. This amounts to 874 // checking to see an unknown klass subtypes a known klass with no subtypes; 875 // this only happens on an exact match. We can shorten this test by 1 load. 876 Node *CmpPNode::Ideal( PhaseGVN *phase, bool can_reshape ) { 877 // Normalize comparisons between Java mirrors into comparisons of the low- 878 // level klass, where a dependent load could be shortened. 879 // 880 // The new pattern has a nice effect of matching the same pattern used in the 881 // fast path of instanceof/checkcast/Class.isInstance(), which allows 882 // redundant exact type check be optimized away by GVN. 883 // For example, in 884 // if (x.getClass() == Foo.class) { 885 // Foo foo = (Foo) x; 886 // // ... use a ... 887 // } 888 // a CmpPNode could be shared between if_acmpne and checkcast 889 { 890 Node* k1 = isa_java_mirror_load(phase, in(1)); 891 Node* k2 = isa_java_mirror_load(phase, in(2)); 892 Node* conk2 = isa_const_java_mirror(phase, in(2)); 893 894 if (k1 && (k2 || conk2)) { 895 Node* lhs = k1; 896 Node* rhs = (k2 != NULL) ? k2 : conk2; 897 this->set_req(1, lhs); 898 this->set_req(2, rhs); 899 return this; 900 } 901 } 902 903 // Constant pointer on right? 904 const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr(); 905 if (t2 == NULL || !t2->klass_is_exact()) 906 return NULL; 907 // Get the constant klass we are comparing to. 908 ciKlass* superklass = t2->klass(); 909 910 // Now check for LoadKlass on left. 911 Node* ldk1 = in(1); 912 if (ldk1->is_DecodeNKlass()) { 913 ldk1 = ldk1->in(1); 914 if (ldk1->Opcode() != Opcodes::Op_LoadNKlass ) 915 return NULL; 916 } else if (ldk1->Opcode() != Opcodes::Op_LoadKlass ) 917 return NULL; 918 // Take apart the address of the LoadKlass: 919 Node* adr1 = ldk1->in(MemNode::Address); 920 intptr_t con2 = 0; 921 Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2); 922 if (ldk2 == NULL) 923 return NULL; 924 if (con2 == oopDesc::klass_offset_in_bytes()) { 925 // We are inspecting an object's concrete class. 926 // Short-circuit the check if the query is abstract. 927 if (superklass->is_interface() || 928 superklass->is_abstract()) { 929 // Make it come out always false: 930 this->set_req(2, phase->makecon(TypePtr::NULL_PTR)); 931 return this; 932 } 933 } 934 935 // Check for a LoadKlass from primary supertype array. 936 // Any nested loadklass from loadklass+con must be from the p.s. array. 937 if (ldk2->is_DecodeNKlass()) { 938 // Keep ldk2 as DecodeN since it could be used in CmpP below. 939 if (ldk2->in(1)->Opcode() != Opcodes::Op_LoadNKlass ) 940 return NULL; 941 } else if (ldk2->Opcode() != Opcodes::Op_LoadKlass) 942 return NULL; 943 944 // Verify that we understand the situation 945 if (con2 != (intptr_t) superklass->super_check_offset()) 946 return NULL; // Might be element-klass loading from array klass 947 948 // If 'superklass' has no subklasses and is not an interface, then we are 949 // assured that the only input which will pass the type check is 950 // 'superklass' itself. 951 // 952 // We could be more liberal here, and allow the optimization on interfaces 953 // which have a single implementor. This would require us to increase the 954 // expressiveness of the add_dependency() mechanism. 955 // %%% Do this after we fix TypeOopPtr: Deps are expressive enough now. 956 957 // Object arrays must have their base element have no subtypes 958 while (superklass->is_obj_array_klass()) { 959 ciType* elem = superklass->as_obj_array_klass()->element_type(); 960 superklass = elem->as_klass(); 961 } 962 if (superklass->is_instance_klass()) { 963 ciInstanceKlass* ik = superklass->as_instance_klass(); 964 if (ik->has_subklass() || ik->is_interface()) return NULL; 965 // Add a dependency if there is a chance that a subclass will be added later. 966 if (!ik->is_final()) { 967 phase->C->dependencies()->assert_leaf_type(ik); 968 } 969 } 970 971 // Bypass the dependent load, and compare directly 972 this->set_req(1,ldk2); 973 974 return this; 975 } 976 977 //============================================================================= 978 //------------------------------sub-------------------------------------------- 979 // Simplify an CmpN (compare 2 pointers) node, based on local information. 980 // If both inputs are constants, compare them. 981 const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const { 982 const TypePtr *r0 = t1->make_ptr(); // Handy access 983 const TypePtr *r1 = t2->make_ptr(); 984 985 // Undefined inputs makes for an undefined result 986 if ((r0 == NULL) || (r1 == NULL) || 987 TypePtr::above_centerline(r0->_ptr) || 988 TypePtr::above_centerline(r1->_ptr)) { 989 return Type::TOP; 990 } 991 if (r0 == r1 && r0->singleton()) { 992 // Equal pointer constants (klasses, nulls, etc.) 993 return TypeInt::CC_EQ; 994 } 995 996 // See if it is 2 unrelated classes. 997 const TypeOopPtr* p0 = r0->isa_oopptr(); 998 const TypeOopPtr* p1 = r1->isa_oopptr(); 999 if (p0 && p1) { 1000 ciKlass* klass0 = p0->klass(); 1001 bool xklass0 = p0->klass_is_exact(); 1002 ciKlass* klass1 = p1->klass(); 1003 bool xklass1 = p1->klass_is_exact(); 1004 int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0); 1005 if (klass0 && klass1 && 1006 kps != 1 && // both or neither are klass pointers 1007 !klass0->is_interface() && // do not trust interfaces 1008 !klass1->is_interface()) { 1009 bool unrelated_classes = false; 1010 // See if neither subclasses the other, or if the class on top 1011 // is precise. In either of these cases, the compare is known 1012 // to fail if at least one of the pointers is provably not null. 1013 if (klass0->equals(klass1)) { // if types are unequal but klasses are equal 1014 // Do nothing; we know nothing for imprecise types 1015 } else if (klass0->is_subtype_of(klass1)) { 1016 // If klass1's type is PRECISE, then classes are unrelated. 1017 unrelated_classes = xklass1; 1018 } else if (klass1->is_subtype_of(klass0)) { 1019 // If klass0's type is PRECISE, then classes are unrelated. 1020 unrelated_classes = xklass0; 1021 } else { // Neither subtypes the other 1022 unrelated_classes = true; 1023 } 1024 if (unrelated_classes) { 1025 // The oops classes are known to be unrelated. If the joined PTRs of 1026 // two oops is not Null and not Bottom, then we are sure that one 1027 // of the two oops is non-null, and the comparison will always fail. 1028 TypePtr::PTR jp = r0->join_ptr(r1->_ptr); 1029 if (jp != TypePtr::Null && jp != TypePtr::BotPTR) { 1030 return TypeInt::CC_GT; 1031 } 1032 } 1033 } 1034 } 1035 1036 // Known constants can be compared exactly 1037 // Null can be distinguished from any NotNull pointers 1038 // Unknown inputs makes an unknown result 1039 if( r0->singleton() ) { 1040 intptr_t bits0 = r0->get_con(); 1041 if( r1->singleton() ) 1042 return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT; 1043 return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC; 1044 } else if( r1->singleton() ) { 1045 intptr_t bits1 = r1->get_con(); 1046 return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC; 1047 } else 1048 return TypeInt::CC; 1049 } 1050 1051 //------------------------------Ideal------------------------------------------ 1052 Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) { 1053 return NULL; 1054 } 1055 1056 //============================================================================= 1057 //------------------------------Value------------------------------------------ 1058 // Simplify an CmpF (compare 2 floats ) node, based on local information. 1059 // If both inputs are constants, compare them. 1060 const Type* CmpFNode::Value(PhaseGVN* phase) const { 1061 const Node* in1 = in(1); 1062 const Node* in2 = in(2); 1063 // Either input is TOP ==> the result is TOP 1064 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 1065 if( t1 == Type::TOP ) return Type::TOP; 1066 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 1067 if( t2 == Type::TOP ) return Type::TOP; 1068 1069 // Not constants? Don't know squat - even if they are the same 1070 // value! If they are NaN's they compare to LT instead of EQ. 1071 const TypeF *tf1 = t1->isa_float_constant(); 1072 const TypeF *tf2 = t2->isa_float_constant(); 1073 if( !tf1 || !tf2 ) return TypeInt::CC; 1074 1075 // This implements the Java bytecode fcmpl, so unordered returns -1. 1076 if( tf1->is_nan() || tf2->is_nan() ) 1077 return TypeInt::CC_LT; 1078 1079 if( tf1->_f < tf2->_f ) return TypeInt::CC_LT; 1080 if( tf1->_f > tf2->_f ) return TypeInt::CC_GT; 1081 assert( tf1->_f == tf2->_f, "do not understand FP behavior" ); 1082 return TypeInt::CC_EQ; 1083 } 1084 1085 1086 //============================================================================= 1087 //------------------------------Value------------------------------------------ 1088 // Simplify an CmpD (compare 2 doubles ) node, based on local information. 1089 // If both inputs are constants, compare them. 1090 const Type* CmpDNode::Value(PhaseGVN* phase) const { 1091 const Node* in1 = in(1); 1092 const Node* in2 = in(2); 1093 // Either input is TOP ==> the result is TOP 1094 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 1095 if( t1 == Type::TOP ) return Type::TOP; 1096 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 1097 if( t2 == Type::TOP ) return Type::TOP; 1098 1099 // Not constants? Don't know squat - even if they are the same 1100 // value! If they are NaN's they compare to LT instead of EQ. 1101 const TypeD *td1 = t1->isa_double_constant(); 1102 const TypeD *td2 = t2->isa_double_constant(); 1103 if( !td1 || !td2 ) return TypeInt::CC; 1104 1105 // This implements the Java bytecode dcmpl, so unordered returns -1. 1106 if( td1->is_nan() || td2->is_nan() ) 1107 return TypeInt::CC_LT; 1108 1109 if( td1->_d < td2->_d ) return TypeInt::CC_LT; 1110 if( td1->_d > td2->_d ) return TypeInt::CC_GT; 1111 assert( td1->_d == td2->_d, "do not understand FP behavior" ); 1112 return TypeInt::CC_EQ; 1113 } 1114 1115 //------------------------------Ideal------------------------------------------ 1116 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){ 1117 // Check if we can change this to a CmpF and remove a ConvD2F operation. 1118 // Change (CMPD (F2D (float)) (ConD value)) 1119 // To (CMPF (float) (ConF value)) 1120 // Valid when 'value' does not lose precision as a float. 1121 // Benefits: eliminates conversion, does not require 24-bit mode 1122 1123 // NaNs prevent commuting operands. This transform works regardless of the 1124 // order of ConD and ConvF2D inputs by preserving the original order. 1125 int idx_f2d = 1; // ConvF2D on left side? 1126 if( in(idx_f2d)->Opcode() != Opcodes::Op_ConvF2D ) 1127 idx_f2d = 2; // No, swap to check for reversed args 1128 int idx_con = 3-idx_f2d; // Check for the constant on other input 1129 1130 if( ConvertCmpD2CmpF && 1131 in(idx_f2d)->Opcode() == Opcodes::Op_ConvF2D && 1132 in(idx_con)->Opcode() == Opcodes::Op_ConD ) { 1133 const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant(); 1134 double t2_value_as_double = t2->_d; 1135 float t2_value_as_float = (float)t2_value_as_double; 1136 if( t2_value_as_double == (double)t2_value_as_float ) { 1137 // Test value can be represented as a float 1138 // Eliminate the conversion to double and create new comparison 1139 Node *new_in1 = in(idx_f2d)->in(1); 1140 Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) ); 1141 if( idx_f2d != 1 ) { // Must flip args to match original order 1142 Node *tmp = new_in1; 1143 new_in1 = new_in2; 1144 new_in2 = tmp; 1145 } 1146 CmpFNode *new_cmp = (Opcode() == Opcodes::Op_CmpD3) 1147 ? new CmpF3Node( new_in1, new_in2 ) 1148 : new CmpFNode ( new_in1, new_in2 ) ; 1149 return new_cmp; // Changed to CmpFNode 1150 } 1151 // Testing value required the precision of a double 1152 } 1153 return NULL; // No change 1154 } 1155 1156 1157 //============================================================================= 1158 //------------------------------cc2logical------------------------------------- 1159 // Convert a condition code type to a logical type 1160 const Type *BoolTest::cc2logical( const Type *CC ) const { 1161 if( CC == Type::TOP ) return Type::TOP; 1162 if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse 1163 const TypeInt *ti = CC->is_int(); 1164 if( ti->is_con() ) { // Only 1 kind of condition codes set? 1165 // Match low order 2 bits 1166 int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0; 1167 if( _test & 4 ) tmp = 1-tmp; // Optionally complement result 1168 return TypeInt::make(tmp); // Boolean result 1169 } 1170 1171 if( CC == TypeInt::CC_GE ) { 1172 if( _test == ge ) return TypeInt::ONE; 1173 if( _test == lt ) return TypeInt::ZERO; 1174 } 1175 if( CC == TypeInt::CC_LE ) { 1176 if( _test == le ) return TypeInt::ONE; 1177 if( _test == gt ) return TypeInt::ZERO; 1178 } 1179 1180 return TypeInt::BOOL; 1181 } 1182 1183 //------------------------------dump_spec------------------------------------- 1184 // Print special per-node info 1185 void BoolTest::dump_on(outputStream *st) const { 1186 const char *msg[] = {"eq","gt","of","lt","ne","le","nof","ge"}; 1187 st->print("%s", msg[_test]); 1188 } 1189 1190 //============================================================================= 1191 uint BoolNode::hash() const { return (Node::hash() << 3)|(_test._test+1); } 1192 uint BoolNode::size_of() const { return sizeof(BoolNode); } 1193 1194 //------------------------------operator==------------------------------------- 1195 uint BoolNode::cmp( const Node &n ) const { 1196 const BoolNode *b = (const BoolNode *)&n; // Cast up 1197 return (_test._test == b->_test._test); 1198 } 1199 1200 //-------------------------------make_predicate-------------------------------- 1201 Node* BoolNode::make_predicate(Node* test_value, PhaseGVN* phase) { 1202 if (test_value->is_Con()) return test_value; 1203 if (test_value->is_Bool()) return test_value; 1204 if (test_value->is_CMove() && 1205 test_value->in(CMoveNode::Condition)->is_Bool()) { 1206 BoolNode* bol = test_value->in(CMoveNode::Condition)->as_Bool(); 1207 const Type* ftype = phase->type(test_value->in(CMoveNode::IfFalse)); 1208 const Type* ttype = phase->type(test_value->in(CMoveNode::IfTrue)); 1209 if (ftype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ttype)) { 1210 return bol; 1211 } else if (ttype == TypeInt::ZERO && !TypeInt::ZERO->higher_equal(ftype)) { 1212 return phase->transform( bol->negate(phase) ); 1213 } 1214 // Else fall through. The CMove gets in the way of the test. 1215 // It should be the case that make_predicate(bol->as_int_value()) == bol. 1216 } 1217 Node* cmp = new CmpINode(test_value, phase->intcon(0)); 1218 cmp = phase->transform(cmp); 1219 Node* bol = new BoolNode(cmp, BoolTest::ne); 1220 return phase->transform(bol); 1221 } 1222 1223 //--------------------------------as_int_value--------------------------------- 1224 Node* BoolNode::as_int_value(PhaseGVN* phase) { 1225 // Inverse to make_predicate. The CMove probably boils down to a Conv2B. 1226 Node* cmov = CMoveNode::make(NULL, this, 1227 phase->intcon(0), phase->intcon(1), 1228 TypeInt::BOOL); 1229 return phase->transform(cmov); 1230 } 1231 1232 //----------------------------------negate------------------------------------- 1233 BoolNode* BoolNode::negate(PhaseGVN* phase) { 1234 return new BoolNode(in(1), _test.negate()); 1235 } 1236 1237 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub 1238 // overflows and we can prove that C is not in the two resulting ranges. 1239 // This optimization is similar to the one performed by CmpUNode::Value(). 1240 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, Opcodes cmp_op, 1241 Opcodes cmp1_op, const TypeInt* cmp2_type) { 1242 // Only optimize eq/ne integer comparison of add/sub 1243 if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1244 (cmp_op == Opcodes::Op_CmpI) && (cmp1_op == Opcodes::Op_AddI || cmp1_op == Opcodes::Op_SubI)) { 1245 // Skip cases were inputs of add/sub are not integers or of bottom type 1246 const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int(); 1247 const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int(); 1248 if ((r0 != NULL) && (r0 != TypeInt::INT) && 1249 (r1 != NULL) && (r1 != TypeInt::INT) && 1250 (cmp2_type != TypeInt::INT)) { 1251 // Compute exact (long) type range of add/sub result 1252 jlong lo_long = r0->_lo; 1253 jlong hi_long = r0->_hi; 1254 if (cmp1_op == Opcodes::Op_AddI) { 1255 lo_long += r1->_lo; 1256 hi_long += r1->_hi; 1257 } else { 1258 lo_long -= r1->_hi; 1259 hi_long -= r1->_lo; 1260 } 1261 // Check for over-/underflow by casting to integer 1262 int lo_int = (int)lo_long; 1263 int hi_int = (int)hi_long; 1264 bool underflow = lo_long != (jlong)lo_int; 1265 bool overflow = hi_long != (jlong)hi_int; 1266 if ((underflow != overflow) && (hi_int < lo_int)) { 1267 // Overflow on one boundary, compute resulting type ranges: 1268 // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT] 1269 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 1270 const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w); 1271 const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w); 1272 // Compare second input of cmp to both type ranges 1273 const Type* sub_tr1 = cmp->sub(tr1, cmp2_type); 1274 const Type* sub_tr2 = cmp->sub(tr2, cmp2_type); 1275 if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) { 1276 // The result of the add/sub will never equal cmp2. Replace BoolNode 1277 // by false (0) if it tests for equality and by true (1) otherwise. 1278 return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1); 1279 } 1280 } 1281 } 1282 } 1283 return NULL; 1284 } 1285 1286 //------------------------------Ideal------------------------------------------ 1287 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1288 // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)". 1289 // This moves the constant to the right. Helps value-numbering. 1290 Node *cmp = in(1); 1291 if( !cmp->is_Sub() ) return NULL; 1292 Opcodes cop = cmp->Opcode(); 1293 if( cop == Opcodes::Op_FastLock || cop == Opcodes::Op_FastUnlock) return NULL; 1294 Node *cmp1 = cmp->in(1); 1295 Node *cmp2 = cmp->in(2); 1296 if( !cmp1 ) return NULL; 1297 1298 if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) { 1299 return NULL; 1300 } 1301 1302 // Constant on left? 1303 Node *con = cmp1; 1304 Opcodes op2 = cmp2->Opcode(); 1305 // Move constants to the right of compare's to canonicalize. 1306 // Do not muck with Opaque1 nodes, as this indicates a loop 1307 // guard that cannot change shape. 1308 if( con->is_Con() && !cmp2->is_Con() && op2 != Opcodes::Op_Opaque1 && 1309 // Because of NaN's, CmpD and CmpF are not commutative 1310 cop != Opcodes::Op_CmpD && cop != Opcodes::Op_CmpF && 1311 // Protect against swapping inputs to a compare when it is used by a 1312 // counted loop exit, which requires maintaining the loop-limit as in(2) 1313 !is_counted_loop_exit_test() ) { 1314 // Ok, commute the constant to the right of the cmp node. 1315 // Clone the Node, getting a new Node of the same class 1316 cmp = cmp->clone(); 1317 // Swap inputs to the clone 1318 cmp->swap_edges(1, 2); 1319 cmp = phase->transform( cmp ); 1320 return new BoolNode( cmp, _test.commute() ); 1321 } 1322 1323 // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)". 1324 // The XOR-1 is an idiom used to flip the sense of a bool. We flip the 1325 // test instead. 1326 Opcodes cmp1_op = cmp1->Opcode(); 1327 const TypeInt* cmp2_type = phase->type(cmp2)->isa_int(); 1328 if (cmp2_type == NULL) return NULL; 1329 Node* j_xor = cmp1; 1330 if( cmp2_type == TypeInt::ZERO && 1331 cmp1_op == Opcodes::Op_XorI && 1332 j_xor->in(1) != j_xor && // An xor of itself is dead 1333 phase->type( j_xor->in(1) ) == TypeInt::BOOL && 1334 phase->type( j_xor->in(2) ) == TypeInt::ONE && 1335 (_test._test == BoolTest::eq || 1336 _test._test == BoolTest::ne) ) { 1337 Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2)); 1338 return new BoolNode( ncmp, _test.negate() ); 1339 } 1340 1341 // Change ((x & m) u<= m) or ((m & x) u<= m) to always true 1342 // Same with ((x & m) u< m+1) and ((m & x) u< m+1) 1343 if (cop == Opcodes::Op_CmpU && 1344 cmp1->Opcode() == Opcodes::Op_AndI) { 1345 Node* bound = NULL; 1346 if (_test._test == BoolTest::le) { 1347 bound = cmp2; 1348 } else if (_test._test == BoolTest::lt && 1349 cmp2->Opcode() == Opcodes::Op_AddI && 1350 cmp2->in(2)->find_int_con(0) == 1) { 1351 bound = cmp2->in(1); 1352 } 1353 if (cmp1->in(2) == bound || cmp1->in(1) == bound) { 1354 return ConINode::make(1); 1355 } 1356 } 1357 1358 // Change ((x & (m - 1)) u< m) into (m > 0) 1359 // This is the off-by-one variant of the above 1360 if (cop == Opcodes::Op_CmpU && 1361 _test._test == BoolTest::lt && 1362 cmp1->Opcode() == Opcodes::Op_AndI) { 1363 Node* l = cmp1->in(1); 1364 Node* r = cmp1->in(2); 1365 for (int repeat = 0; repeat < 2; repeat++) { 1366 bool match = r->Opcode() == Opcodes::Op_AddI && r->in(2)->find_int_con(0) == -1 && 1367 r->in(1) == cmp2; 1368 if (match) { 1369 // arraylength known to be non-negative, so a (arraylength != 0) is sufficient, 1370 // but to be compatible with the array range check pattern, use (arraylength u> 0) 1371 Node* ncmp = cmp2->Opcode() == Opcodes::Op_LoadRange 1372 ? phase->transform(new CmpUNode(cmp2, phase->intcon(0))) 1373 : phase->transform(new CmpINode(cmp2, phase->intcon(0))); 1374 return new BoolNode(ncmp, BoolTest::gt); 1375 } else { 1376 // commute and try again 1377 l = cmp1->in(2); 1378 r = cmp1->in(1); 1379 } 1380 } 1381 } 1382 1383 // Change (arraylength <= 0) or (arraylength == 0) 1384 // into (arraylength u<= 0) 1385 // Also change (arraylength != 0) into (arraylength u> 0) 1386 // The latter version matches the code pattern generated for 1387 // array range checks, which will more likely be optimized later. 1388 if (cop == Opcodes::Op_CmpI && 1389 cmp1->Opcode() == Opcodes::Op_LoadRange && 1390 cmp2->find_int_con(-1) == 0) { 1391 if (_test._test == BoolTest::le || _test._test == BoolTest::eq) { 1392 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1393 return new BoolNode(ncmp, BoolTest::le); 1394 } else if (_test._test == BoolTest::ne) { 1395 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1396 return new BoolNode(ncmp, BoolTest::gt); 1397 } 1398 } 1399 1400 // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)". 1401 // This is a standard idiom for branching on a boolean value. 1402 Node *c2b = cmp1; 1403 if( cmp2_type == TypeInt::ZERO && 1404 cmp1_op == Opcodes::Op_Conv2B && 1405 (_test._test == BoolTest::eq || 1406 _test._test == BoolTest::ne) ) { 1407 Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int() 1408 ? (Node*)new CmpINode(c2b->in(1),cmp2) 1409 : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR)) 1410 ); 1411 return new BoolNode( ncmp, _test._test ); 1412 } 1413 1414 // Comparing a SubI against a zero is equal to comparing the SubI 1415 // arguments directly. This only works for eq and ne comparisons 1416 // due to possible integer overflow. 1417 if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1418 (cop == Opcodes::Op_CmpI) && 1419 (cmp1->Opcode() == Opcodes::Op_SubI) && 1420 ( cmp2_type == TypeInt::ZERO ) ) { 1421 Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2))); 1422 return new BoolNode( ncmp, _test._test ); 1423 } 1424 1425 // Change (-A vs 0) into (A vs 0) by commuting the test. Disallow in the 1426 // most general case because negating 0x80000000 does nothing. Needed for 1427 // the CmpF3/SubI/CmpI idiom. 1428 if( cop == Opcodes::Op_CmpI && 1429 cmp1->Opcode() == Opcodes::Op_SubI && 1430 cmp2_type == TypeInt::ZERO && 1431 phase->type( cmp1->in(1) ) == TypeInt::ZERO && 1432 phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) { 1433 Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2)); 1434 return new BoolNode( ncmp, _test.commute() ); 1435 } 1436 1437 // Try to optimize signed integer comparison 1438 return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type); 1439 1440 // The transformation below is not valid for either signed or unsigned 1441 // comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE. 1442 // This transformation can be resurrected when we are able to 1443 // make inferences about the range of values being subtracted from 1444 // (or added to) relative to the wraparound point. 1445 // 1446 // // Remove +/-1's if possible. 1447 // // "X <= Y-1" becomes "X < Y" 1448 // // "X+1 <= Y" becomes "X < Y" 1449 // // "X < Y+1" becomes "X <= Y" 1450 // // "X-1 < Y" becomes "X <= Y" 1451 // // Do not this to compares off of the counted-loop-end. These guys are 1452 // // checking the trip counter and they want to use the post-incremented 1453 // // counter. If they use the PRE-incremented counter, then the counter has 1454 // // to be incremented in a private block on a loop backedge. 1455 // if( du && du->cnt(this) && du->out(this)[0]->Opcode() == Op_CountedLoopEnd ) 1456 // return NULL; 1457 // #ifndef PRODUCT 1458 // // Do not do this in a wash GVN pass during verification. 1459 // // Gets triggered by too many simple optimizations to be bothered with 1460 // // re-trying it again and again. 1461 // if( !phase->allow_progress() ) return NULL; 1462 // #endif 1463 // // Not valid for unsigned compare because of corner cases in involving zero. 1464 // // For example, replacing "X-1 <u Y" with "X <=u Y" fails to throw an 1465 // // exception in case X is 0 (because 0-1 turns into 4billion unsigned but 1466 // // "0 <=u Y" is always true). 1467 // if( cmp->Opcode() == Op_CmpU ) return NULL; 1468 // int cmp2_op = cmp2->Opcode(); 1469 // if( _test._test == BoolTest::le ) { 1470 // if( cmp1_op == Op_AddI && 1471 // phase->type( cmp1->in(2) ) == TypeInt::ONE ) 1472 // return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::lt ); 1473 // else if( cmp2_op == Op_AddI && 1474 // phase->type( cmp2->in(2) ) == TypeInt::MINUS_1 ) 1475 // return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::lt ); 1476 // } else if( _test._test == BoolTest::lt ) { 1477 // if( cmp1_op == Op_AddI && 1478 // phase->type( cmp1->in(2) ) == TypeInt::MINUS_1 ) 1479 // return clone_cmp( cmp, cmp1->in(1), cmp2, phase, BoolTest::le ); 1480 // else if( cmp2_op == Op_AddI && 1481 // phase->type( cmp2->in(2) ) == TypeInt::ONE ) 1482 // return clone_cmp( cmp, cmp1, cmp2->in(1), phase, BoolTest::le ); 1483 // } 1484 } 1485 1486 //------------------------------Value------------------------------------------ 1487 // Simplify a Bool (convert condition codes to boolean (1 or 0)) node, 1488 // based on local information. If the input is constant, do it. 1489 const Type* BoolNode::Value(PhaseGVN* phase) const { 1490 return _test.cc2logical( phase->type( in(1) ) ); 1491 } 1492 1493 #ifndef PRODUCT 1494 //------------------------------dump_spec-------------------------------------- 1495 // Dump special per-node info 1496 void BoolNode::dump_spec(outputStream *st) const { 1497 st->print("["); 1498 _test.dump_on(st); 1499 st->print("]"); 1500 } 1501 1502 //-------------------------------related--------------------------------------- 1503 // A BoolNode's related nodes are all of its data inputs, and all of its 1504 // outputs until control nodes are hit, which are included. In compact 1505 // representation, inputs till level 3 and immediate outputs are included. 1506 void BoolNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const { 1507 if (compact) { 1508 this->collect_nodes(in_rel, 3, false, true); 1509 this->collect_nodes(out_rel, -1, false, false); 1510 } else { 1511 this->collect_nodes_in_all_data(in_rel, false); 1512 this->collect_nodes_out_all_ctrl_boundary(out_rel); 1513 } 1514 } 1515 #endif 1516 1517 //----------------------is_counted_loop_exit_test------------------------------ 1518 // Returns true if node is used by a counted loop node. 1519 bool BoolNode::is_counted_loop_exit_test() { 1520 for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) { 1521 Node* use = fast_out(i); 1522 if (use->is_CountedLoopEnd()) { 1523 return true; 1524 } 1525 } 1526 return false; 1527 } 1528 1529 //============================================================================= 1530 //------------------------------Value------------------------------------------ 1531 // Compute sqrt 1532 const Type* SqrtDNode::Value(PhaseGVN* phase) const { 1533 const Type *t1 = phase->type( in(1) ); 1534 if( t1 == Type::TOP ) return Type::TOP; 1535 if( t1->base() != Type::DoubleCon ) return Type::DOUBLE; 1536 double d = t1->getd(); 1537 if( d < 0.0 ) return Type::DOUBLE; 1538 return TypeD::make( sqrt( d ) ); 1539 }