1 /* 2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.inline.hpp" 27 #include "opto/addnode.hpp" 28 #include "opto/connode.hpp" 29 #include "opto/memnode.hpp" 30 #include "opto/mulnode.hpp" 31 #include "opto/phaseX.hpp" 32 #include "opto/subnode.hpp" 33 34 // Portions of code courtesy of Clifford Click 35 36 37 //============================================================================= 38 //------------------------------hash------------------------------------------- 39 // Hash function over MulNodes. Needs to be commutative; i.e., I swap 40 // (commute) inputs to MulNodes willy-nilly so the hash function must return 41 // the same value in the presence of edge swapping. 42 uint MulNode::hash() const { 43 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode(); 44 } 45 46 //------------------------------Identity--------------------------------------- 47 // Multiplying a one preserves the other argument 48 Node *MulNode::Identity( PhaseTransform *phase ) { 49 register const Type *one = mul_id(); // The multiplicative identity 50 if( phase->type( in(1) )->higher_equal( one ) ) return in(2); 51 if( phase->type( in(2) )->higher_equal( one ) ) return in(1); 52 53 return this; 54 } 55 56 //------------------------------Ideal------------------------------------------ 57 // We also canonicalize the Node, moving constants to the right input, 58 // and flatten expressions (so that 1+x+2 becomes x+3). 59 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) { 60 const Type *t1 = phase->type( in(1) ); 61 const Type *t2 = phase->type( in(2) ); 62 Node *progress = NULL; // Progress flag 63 // We are OK if right is a constant, or right is a load and 64 // left is a non-constant. 65 if( !(t2->singleton() || 66 (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) { 67 if( t1->singleton() || // Left input is a constant? 68 // Otherwise, sort inputs (commutativity) to help value numbering. 69 (in(1)->_idx > in(2)->_idx) ) { 70 swap_edges(1, 2); 71 const Type *t = t1; 72 t1 = t2; 73 t2 = t; 74 progress = this; // Made progress 75 } 76 } 77 78 // If the right input is a constant, and the left input is a product of a 79 // constant, flatten the expression tree. 80 uint op = Opcode(); 81 if( t2->singleton() && // Right input is a constant? 82 op != Op_MulF && // Float & double cannot reassociate 83 op != Op_MulD ) { 84 if( t2 == Type::TOP ) return NULL; 85 Node *mul1 = in(1); 86 #ifdef ASSERT 87 // Check for dead loop 88 int op1 = mul1->Opcode(); 89 if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) || 90 ( op1 == mul_opcode() || op1 == add_opcode() ) && 91 ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) || 92 phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) ) 93 assert(false, "dead loop in MulNode::Ideal"); 94 #endif 95 96 if( mul1->Opcode() == mul_opcode() ) { // Left input is a multiply? 97 // Mul of a constant? 98 const Type *t12 = phase->type( mul1->in(2) ); 99 if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant? 100 // Compute new constant; check for overflow 101 const Type *tcon01 = ((MulNode*)mul1)->mul_ring(t2,t12); 102 if( tcon01->singleton() ) { 103 // The Mul of the flattened expression 104 set_req(1, mul1->in(1)); 105 set_req(2, phase->makecon( tcon01 )); 106 t2 = tcon01; 107 progress = this; // Made progress 108 } 109 } 110 } 111 // If the right input is a constant, and the left input is an add of a 112 // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0 113 const Node *add1 = in(1); 114 if( add1->Opcode() == add_opcode() ) { // Left input is an add? 115 // Add of a constant? 116 const Type *t12 = phase->type( add1->in(2) ); 117 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant? 118 assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" ); 119 // Compute new constant; check for overflow 120 const Type *tcon01 = mul_ring(t2,t12); 121 if( tcon01->singleton() ) { 122 123 // Convert (X+con1)*con0 into X*con0 124 Node *mul = clone(); // mul = ()*con0 125 mul->set_req(1,add1->in(1)); // mul = X*con0 126 mul = phase->transform(mul); 127 128 Node *add2 = add1->clone(); 129 add2->set_req(1, mul); // X*con0 + con0*con1 130 add2->set_req(2, phase->makecon(tcon01) ); 131 progress = add2; 132 } 133 } 134 } // End of is left input an add 135 } // End of is right input a Mul 136 137 return progress; 138 } 139 140 //------------------------------Value----------------------------------------- 141 const Type *MulNode::Value( PhaseTransform *phase ) const { 142 const Type *t1 = phase->type( in(1) ); 143 const Type *t2 = phase->type( in(2) ); 144 // Either input is TOP ==> the result is TOP 145 if( t1 == Type::TOP ) return Type::TOP; 146 if( t2 == Type::TOP ) return Type::TOP; 147 148 // Either input is ZERO ==> the result is ZERO. 149 // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0 150 int op = Opcode(); 151 if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) { 152 const Type *zero = add_id(); // The multiplicative zero 153 if( t1->higher_equal( zero ) ) return zero; 154 if( t2->higher_equal( zero ) ) return zero; 155 } 156 157 // Either input is BOTTOM ==> the result is the local BOTTOM 158 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM ) 159 return bottom_type(); 160 161 #if defined(IA32) 162 // Can't trust native compilers to properly fold strict double 163 // multiplication with round-to-zero on this platform. 164 if (op == Op_MulD && phase->C->method()->is_strict()) { 165 return TypeD::DOUBLE; 166 } 167 #endif 168 169 return mul_ring(t1,t2); // Local flavor of type multiplication 170 } 171 172 173 //============================================================================= 174 //------------------------------Ideal------------------------------------------ 175 // Check for power-of-2 multiply, then try the regular MulNode::Ideal 176 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) { 177 // Swap constant to right 178 jint con; 179 if ((con = in(1)->find_int_con(0)) != 0) { 180 swap_edges(1, 2); 181 // Finish rest of method to use info in 'con' 182 } else if ((con = in(2)->find_int_con(0)) == 0) { 183 return MulNode::Ideal(phase, can_reshape); 184 } 185 186 // Now we have a constant Node on the right and the constant in con 187 if( con == 0 ) return NULL; // By zero is handled by Value call 188 if( con == 1 ) return NULL; // By one is handled by Identity call 189 190 // Check for negative constant; if so negate the final result 191 bool sign_flip = false; 192 if( con < 0 ) { 193 con = -con; 194 sign_flip = true; 195 } 196 197 // Get low bit; check for being the only bit 198 Node *res = NULL; 199 jint bit1 = con & -con; // Extract low bit 200 if( bit1 == con ) { // Found a power of 2? 201 res = new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ); 202 } else { 203 204 // Check for constant with 2 bits set 205 jint bit2 = con-bit1; 206 bit2 = bit2 & -bit2; // Extract 2nd bit 207 if( bit2 + bit1 == con ) { // Found all bits in con? 208 Node *n1 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) ); 209 Node *n2 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) ); 210 res = new (phase->C) AddINode( n2, n1 ); 211 212 } else if (is_power_of_2(con+1)) { 213 // Sleezy: power-of-2 -1. Next time be generic. 214 jint temp = (jint) (con + 1); 215 Node *n1 = phase->transform( new (phase->C) LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) ); 216 res = new (phase->C) SubINode( n1, in(1) ); 217 } else { 218 return MulNode::Ideal(phase, can_reshape); 219 } 220 } 221 222 if( sign_flip ) { // Need to negate result? 223 res = phase->transform(res);// Transform, before making the zero con 224 res = new (phase->C) SubINode(phase->intcon(0),res); 225 } 226 227 return res; // Return final result 228 } 229 230 //------------------------------mul_ring--------------------------------------- 231 // Compute the product type of two integer ranges into this node. 232 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const { 233 const TypeInt *r0 = t0->is_int(); // Handy access 234 const TypeInt *r1 = t1->is_int(); 235 236 // Fetch endpoints of all ranges 237 int32 lo0 = r0->_lo; 238 double a = (double)lo0; 239 int32 hi0 = r0->_hi; 240 double b = (double)hi0; 241 int32 lo1 = r1->_lo; 242 double c = (double)lo1; 243 int32 hi1 = r1->_hi; 244 double d = (double)hi1; 245 246 // Compute all endpoints & check for overflow 247 int32 A = lo0*lo1; 248 if( (double)A != a*c ) return TypeInt::INT; // Overflow? 249 int32 B = lo0*hi1; 250 if( (double)B != a*d ) return TypeInt::INT; // Overflow? 251 int32 C = hi0*lo1; 252 if( (double)C != b*c ) return TypeInt::INT; // Overflow? 253 int32 D = hi0*hi1; 254 if( (double)D != b*d ) return TypeInt::INT; // Overflow? 255 256 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints 257 else { lo0 = B; hi0 = A; } 258 if( C < D ) { 259 if( C < lo0 ) lo0 = C; 260 if( D > hi0 ) hi0 = D; 261 } else { 262 if( D < lo0 ) lo0 = D; 263 if( C > hi0 ) hi0 = C; 264 } 265 return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen)); 266 } 267 268 269 //============================================================================= 270 //------------------------------Ideal------------------------------------------ 271 // Check for power-of-2 multiply, then try the regular MulNode::Ideal 272 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 273 // Swap constant to right 274 jlong con; 275 if ((con = in(1)->find_long_con(0)) != 0) { 276 swap_edges(1, 2); 277 // Finish rest of method to use info in 'con' 278 } else if ((con = in(2)->find_long_con(0)) == 0) { 279 return MulNode::Ideal(phase, can_reshape); 280 } 281 282 // Now we have a constant Node on the right and the constant in con 283 if( con == CONST64(0) ) return NULL; // By zero is handled by Value call 284 if( con == CONST64(1) ) return NULL; // By one is handled by Identity call 285 286 // Check for negative constant; if so negate the final result 287 bool sign_flip = false; 288 if( con < 0 ) { 289 con = -con; 290 sign_flip = true; 291 } 292 293 // Get low bit; check for being the only bit 294 Node *res = NULL; 295 jlong bit1 = con & -con; // Extract low bit 296 if( bit1 == con ) { // Found a power of 2? 297 res = new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ); 298 } else { 299 300 // Check for constant with 2 bits set 301 jlong bit2 = con-bit1; 302 bit2 = bit2 & -bit2; // Extract 2nd bit 303 if( bit2 + bit1 == con ) { // Found all bits in con? 304 Node *n1 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) ); 305 Node *n2 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) ); 306 res = new (phase->C) AddLNode( n2, n1 ); 307 308 } else if (is_power_of_2_long(con+1)) { 309 // Sleezy: power-of-2 -1. Next time be generic. 310 jlong temp = (jlong) (con + 1); 311 Node *n1 = phase->transform( new (phase->C) LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) ); 312 res = new (phase->C) SubLNode( n1, in(1) ); 313 } else { 314 return MulNode::Ideal(phase, can_reshape); 315 } 316 } 317 318 if( sign_flip ) { // Need to negate result? 319 res = phase->transform(res);// Transform, before making the zero con 320 res = new (phase->C) SubLNode(phase->longcon(0),res); 321 } 322 323 return res; // Return final result 324 } 325 326 //------------------------------mul_ring--------------------------------------- 327 // Compute the product type of two integer ranges into this node. 328 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const { 329 const TypeLong *r0 = t0->is_long(); // Handy access 330 const TypeLong *r1 = t1->is_long(); 331 332 // Fetch endpoints of all ranges 333 jlong lo0 = r0->_lo; 334 double a = (double)lo0; 335 jlong hi0 = r0->_hi; 336 double b = (double)hi0; 337 jlong lo1 = r1->_lo; 338 double c = (double)lo1; 339 jlong hi1 = r1->_hi; 340 double d = (double)hi1; 341 342 // Compute all endpoints & check for overflow 343 jlong A = lo0*lo1; 344 if( (double)A != a*c ) return TypeLong::LONG; // Overflow? 345 jlong B = lo0*hi1; 346 if( (double)B != a*d ) return TypeLong::LONG; // Overflow? 347 jlong C = hi0*lo1; 348 if( (double)C != b*c ) return TypeLong::LONG; // Overflow? 349 jlong D = hi0*hi1; 350 if( (double)D != b*d ) return TypeLong::LONG; // Overflow? 351 352 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints 353 else { lo0 = B; hi0 = A; } 354 if( C < D ) { 355 if( C < lo0 ) lo0 = C; 356 if( D > hi0 ) hi0 = D; 357 } else { 358 if( D < lo0 ) lo0 = D; 359 if( C > hi0 ) hi0 = C; 360 } 361 return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen)); 362 } 363 364 //============================================================================= 365 //------------------------------mul_ring--------------------------------------- 366 // Compute the product type of two double ranges into this node. 367 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const { 368 if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT; 369 return TypeF::make( t0->getf() * t1->getf() ); 370 } 371 372 //============================================================================= 373 //------------------------------mul_ring--------------------------------------- 374 // Compute the product type of two double ranges into this node. 375 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const { 376 if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE; 377 // We must be multiplying 2 double constants. 378 return TypeD::make( t0->getd() * t1->getd() ); 379 } 380 381 //============================================================================= 382 //------------------------------Value------------------------------------------ 383 const Type *MulHiLNode::Value( PhaseTransform *phase ) const { 384 // Either input is TOP ==> the result is TOP 385 const Type *t1 = phase->type( in(1) ); 386 const Type *t2 = phase->type( in(2) ); 387 if( t1 == Type::TOP ) return Type::TOP; 388 if( t2 == Type::TOP ) return Type::TOP; 389 390 // Either input is BOTTOM ==> the result is the local BOTTOM 391 const Type *bot = bottom_type(); 392 if( (t1 == bot) || (t2 == bot) || 393 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 394 return bot; 395 396 // It is not worth trying to constant fold this stuff! 397 return TypeLong::LONG; 398 } 399 400 //============================================================================= 401 //------------------------------mul_ring--------------------------------------- 402 // Supplied function returns the product of the inputs IN THE CURRENT RING. 403 // For the logical operations the ring's MUL is really a logical AND function. 404 // This also type-checks the inputs for sanity. Guaranteed never to 405 // be passed a TOP or BOTTOM type, these are filtered out by pre-check. 406 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const { 407 const TypeInt *r0 = t0->is_int(); // Handy access 408 const TypeInt *r1 = t1->is_int(); 409 int widen = MAX2(r0->_widen,r1->_widen); 410 411 // If either input is a constant, might be able to trim cases 412 if( !r0->is_con() && !r1->is_con() ) 413 return TypeInt::INT; // No constants to be had 414 415 // Both constants? Return bits 416 if( r0->is_con() && r1->is_con() ) 417 return TypeInt::make( r0->get_con() & r1->get_con() ); 418 419 if( r0->is_con() && r0->get_con() > 0 ) 420 return TypeInt::make(0, r0->get_con(), widen); 421 422 if( r1->is_con() && r1->get_con() > 0 ) 423 return TypeInt::make(0, r1->get_con(), widen); 424 425 if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) { 426 return TypeInt::BOOL; 427 } 428 429 return TypeInt::INT; // No constants to be had 430 } 431 432 //------------------------------Identity--------------------------------------- 433 // Masking off the high bits of an unsigned load is not required 434 Node *AndINode::Identity( PhaseTransform *phase ) { 435 436 // x & x => x 437 if (phase->eqv(in(1), in(2))) return in(1); 438 439 Node* in1 = in(1); 440 uint op = in1->Opcode(); 441 const TypeInt* t2 = phase->type(in(2))->isa_int(); 442 if (t2 && t2->is_con()) { 443 int con = t2->get_con(); 444 // Masking off high bits which are always zero is useless. 445 const TypeInt* t1 = phase->type( in(1) )->isa_int(); 446 if (t1 != NULL && t1->_lo >= 0) { 447 jint t1_support = right_n_bits(1 + log2_intptr(t1->_hi)); 448 if ((t1_support & con) == t1_support) 449 return in1; 450 } 451 // Masking off the high bits of a unsigned-shift-right is not 452 // needed either. 453 if (op == Op_URShiftI) { 454 const TypeInt* t12 = phase->type(in1->in(2))->isa_int(); 455 if (t12 && t12->is_con()) { // Shift is by a constant 456 int shift = t12->get_con(); 457 shift &= BitsPerJavaInteger - 1; // semantics of Java shifts 458 int mask = max_juint >> shift; 459 if ((mask & con) == mask) // If AND is useless, skip it 460 return in1; 461 } 462 } 463 } 464 return MulNode::Identity(phase); 465 } 466 467 //------------------------------Ideal------------------------------------------ 468 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) { 469 // Special case constant AND mask 470 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 471 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape); 472 const int mask = t2->get_con(); 473 Node *load = in(1); 474 uint lop = load->Opcode(); 475 476 // Masking bits off of a Character? Hi bits are already zero. 477 if( lop == Op_LoadUS && 478 (mask & 0xFFFF0000) ) // Can we make a smaller mask? 479 return new (phase->C) AndINode(load,phase->intcon(mask&0xFFFF)); 480 481 // Masking bits off of a Short? Loading a Character does some masking 482 if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) { 483 Node *ldus = new (phase->C) LoadUSNode(load->in(MemNode::Control), 484 load->in(MemNode::Memory), 485 load->in(MemNode::Address), 486 load->adr_type()); 487 ldus = phase->transform(ldus); 488 return new (phase->C) AndINode(ldus, phase->intcon(mask & 0xFFFF)); 489 } 490 491 // Masking sign bits off of a Byte? Do an unsigned byte load plus 492 // an and. 493 if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) { 494 Node* ldub = new (phase->C) LoadUBNode(load->in(MemNode::Control), 495 load->in(MemNode::Memory), 496 load->in(MemNode::Address), 497 load->adr_type()); 498 ldub = phase->transform(ldub); 499 return new (phase->C) AndINode(ldub, phase->intcon(mask)); 500 } 501 502 // Masking off sign bits? Dont make them! 503 if( lop == Op_RShiftI ) { 504 const TypeInt *t12 = phase->type(load->in(2))->isa_int(); 505 if( t12 && t12->is_con() ) { // Shift is by a constant 506 int shift = t12->get_con(); 507 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 508 const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift); 509 // If the AND'ing of the 2 masks has no bits, then only original shifted 510 // bits survive. NO sign-extension bits survive the maskings. 511 if( (sign_bits_mask & mask) == 0 ) { 512 // Use zero-fill shift instead 513 Node *zshift = phase->transform(new (phase->C) URShiftINode(load->in(1),load->in(2))); 514 return new (phase->C) AndINode( zshift, in(2) ); 515 } 516 } 517 } 518 519 // Check for 'negate/and-1', a pattern emitted when someone asks for 520 // 'mod 2'. Negate leaves the low order bit unchanged (think: complement 521 // plus 1) and the mask is of the low order bit. Skip the negate. 522 if( lop == Op_SubI && mask == 1 && load->in(1) && 523 phase->type(load->in(1)) == TypeInt::ZERO ) 524 return new (phase->C) AndINode( load->in(2), in(2) ); 525 526 return MulNode::Ideal(phase, can_reshape); 527 } 528 529 //============================================================================= 530 //------------------------------mul_ring--------------------------------------- 531 // Supplied function returns the product of the inputs IN THE CURRENT RING. 532 // For the logical operations the ring's MUL is really a logical AND function. 533 // This also type-checks the inputs for sanity. Guaranteed never to 534 // be passed a TOP or BOTTOM type, these are filtered out by pre-check. 535 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const { 536 const TypeLong *r0 = t0->is_long(); // Handy access 537 const TypeLong *r1 = t1->is_long(); 538 int widen = MAX2(r0->_widen,r1->_widen); 539 540 // If either input is a constant, might be able to trim cases 541 if( !r0->is_con() && !r1->is_con() ) 542 return TypeLong::LONG; // No constants to be had 543 544 // Both constants? Return bits 545 if( r0->is_con() && r1->is_con() ) 546 return TypeLong::make( r0->get_con() & r1->get_con() ); 547 548 if( r0->is_con() && r0->get_con() > 0 ) 549 return TypeLong::make(CONST64(0), r0->get_con(), widen); 550 551 if( r1->is_con() && r1->get_con() > 0 ) 552 return TypeLong::make(CONST64(0), r1->get_con(), widen); 553 554 return TypeLong::LONG; // No constants to be had 555 } 556 557 //------------------------------Identity--------------------------------------- 558 // Masking off the high bits of an unsigned load is not required 559 Node *AndLNode::Identity( PhaseTransform *phase ) { 560 561 // x & x => x 562 if (phase->eqv(in(1), in(2))) return in(1); 563 564 Node *usr = in(1); 565 const TypeLong *t2 = phase->type( in(2) )->isa_long(); 566 if( t2 && t2->is_con() ) { 567 jlong con = t2->get_con(); 568 // Masking off high bits which are always zero is useless. 569 const TypeLong* t1 = phase->type( in(1) )->isa_long(); 570 if (t1 != NULL && t1->_lo >= 0) { 571 jlong t1_support = ((jlong)1 << (1 + log2_long(t1->_hi))) - 1; 572 if ((t1_support & con) == t1_support) 573 return usr; 574 } 575 uint lop = usr->Opcode(); 576 // Masking off the high bits of a unsigned-shift-right is not 577 // needed either. 578 if( lop == Op_URShiftL ) { 579 const TypeInt *t12 = phase->type( usr->in(2) )->isa_int(); 580 if( t12 && t12->is_con() ) { // Shift is by a constant 581 int shift = t12->get_con(); 582 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 583 jlong mask = max_julong >> shift; 584 if( (mask&con) == mask ) // If AND is useless, skip it 585 return usr; 586 } 587 } 588 } 589 return MulNode::Identity(phase); 590 } 591 592 //------------------------------Ideal------------------------------------------ 593 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 594 // Special case constant AND mask 595 const TypeLong *t2 = phase->type( in(2) )->isa_long(); 596 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape); 597 const jlong mask = t2->get_con(); 598 599 Node* in1 = in(1); 600 uint op = in1->Opcode(); 601 602 // Are we masking a long that was converted from an int with a mask 603 // that fits in 32-bits? Commute them and use an AndINode. Don't 604 // convert masks which would cause a sign extension of the integer 605 // value. This check includes UI2L masks (0x00000000FFFFFFFF) which 606 // would be optimized away later in Identity. 607 if (op == Op_ConvI2L && (mask & CONST64(0xFFFFFFFF80000000)) == 0) { 608 Node* andi = new (phase->C) AndINode(in1->in(1), phase->intcon(mask)); 609 andi = phase->transform(andi); 610 return new (phase->C) ConvI2LNode(andi); 611 } 612 613 // Masking off sign bits? Dont make them! 614 if (op == Op_RShiftL) { 615 const TypeInt* t12 = phase->type(in1->in(2))->isa_int(); 616 if( t12 && t12->is_con() ) { // Shift is by a constant 617 int shift = t12->get_con(); 618 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 619 const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1); 620 // If the AND'ing of the 2 masks has no bits, then only original shifted 621 // bits survive. NO sign-extension bits survive the maskings. 622 if( (sign_bits_mask & mask) == 0 ) { 623 // Use zero-fill shift instead 624 Node *zshift = phase->transform(new (phase->C) URShiftLNode(in1->in(1), in1->in(2))); 625 return new (phase->C) AndLNode(zshift, in(2)); 626 } 627 } 628 } 629 630 return MulNode::Ideal(phase, can_reshape); 631 } 632 633 //============================================================================= 634 //------------------------------Identity--------------------------------------- 635 Node *LShiftINode::Identity( PhaseTransform *phase ) { 636 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 637 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this; 638 } 639 640 //------------------------------Ideal------------------------------------------ 641 // If the right input is a constant, and the left input is an add of a 642 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0 643 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 644 const Type *t = phase->type( in(2) ); 645 if( t == Type::TOP ) return NULL; // Right input is dead 646 const TypeInt *t2 = t->isa_int(); 647 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 648 const int con = t2->get_con() & ( BitsPerInt - 1 ); // masked shift count 649 650 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count 651 652 // Left input is an add of a constant? 653 Node *add1 = in(1); 654 int add1_op = add1->Opcode(); 655 if( add1_op == Op_AddI ) { // Left input is an add? 656 assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" ); 657 const TypeInt *t12 = phase->type(add1->in(2))->isa_int(); 658 if( t12 && t12->is_con() ){ // Left input is an add of a con? 659 // Transform is legal, but check for profit. Avoid breaking 'i2s' 660 // and 'i2b' patterns which typically fold into 'StoreC/StoreB'. 661 if( con < 16 ) { 662 // Compute X << con0 663 Node *lsh = phase->transform( new (phase->C) LShiftINode( add1->in(1), in(2) ) ); 664 // Compute X<<con0 + (con1<<con0) 665 return new (phase->C) AddINode( lsh, phase->intcon(t12->get_con() << con)); 666 } 667 } 668 } 669 670 // Check for "(x>>c0)<<c0" which just masks off low bits 671 if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) && 672 add1->in(2) == in(2) ) 673 // Convert to "(x & -(1<<c0))" 674 return new (phase->C) AndINode(add1->in(1),phase->intcon( -(1<<con))); 675 676 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits 677 if( add1_op == Op_AndI ) { 678 Node *add2 = add1->in(1); 679 int add2_op = add2->Opcode(); 680 if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) && 681 add2->in(2) == in(2) ) { 682 // Convert to "(x & (Y<<c0))" 683 Node *y_sh = phase->transform( new (phase->C) LShiftINode( add1->in(2), in(2) ) ); 684 return new (phase->C) AndINode( add2->in(1), y_sh ); 685 } 686 } 687 688 // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits 689 // before shifting them away. 690 const jint bits_mask = right_n_bits(BitsPerJavaInteger-con); 691 if( add1_op == Op_AndI && 692 phase->type(add1->in(2)) == TypeInt::make( bits_mask ) ) 693 return new (phase->C) LShiftINode( add1->in(1), in(2) ); 694 695 return NULL; 696 } 697 698 //------------------------------Value------------------------------------------ 699 // A LShiftINode shifts its input2 left by input1 amount. 700 const Type *LShiftINode::Value( PhaseTransform *phase ) const { 701 const Type *t1 = phase->type( in(1) ); 702 const Type *t2 = phase->type( in(2) ); 703 // Either input is TOP ==> the result is TOP 704 if( t1 == Type::TOP ) return Type::TOP; 705 if( t2 == Type::TOP ) return Type::TOP; 706 707 // Left input is ZERO ==> the result is ZERO. 708 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 709 // Shift by zero does nothing 710 if( t2 == TypeInt::ZERO ) return t1; 711 712 // Either input is BOTTOM ==> the result is BOTTOM 713 if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) || 714 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 715 return TypeInt::INT; 716 717 const TypeInt *r1 = t1->is_int(); // Handy access 718 const TypeInt *r2 = t2->is_int(); // Handy access 719 720 if (!r2->is_con()) 721 return TypeInt::INT; 722 723 uint shift = r2->get_con(); 724 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 725 // Shift by a multiple of 32 does nothing: 726 if (shift == 0) return t1; 727 728 // If the shift is a constant, shift the bounds of the type, 729 // unless this could lead to an overflow. 730 if (!r1->is_con()) { 731 jint lo = r1->_lo, hi = r1->_hi; 732 if (((lo << shift) >> shift) == lo && 733 ((hi << shift) >> shift) == hi) { 734 // No overflow. The range shifts up cleanly. 735 return TypeInt::make((jint)lo << (jint)shift, 736 (jint)hi << (jint)shift, 737 MAX2(r1->_widen,r2->_widen)); 738 } 739 return TypeInt::INT; 740 } 741 742 return TypeInt::make( (jint)r1->get_con() << (jint)shift ); 743 } 744 745 //============================================================================= 746 //------------------------------Identity--------------------------------------- 747 Node *LShiftLNode::Identity( PhaseTransform *phase ) { 748 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 749 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 750 } 751 752 //------------------------------Ideal------------------------------------------ 753 // If the right input is a constant, and the left input is an add of a 754 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0 755 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 756 const Type *t = phase->type( in(2) ); 757 if( t == Type::TOP ) return NULL; // Right input is dead 758 const TypeInt *t2 = t->isa_int(); 759 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 760 const int con = t2->get_con() & ( BitsPerLong - 1 ); // masked shift count 761 762 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count 763 764 // Left input is an add of a constant? 765 Node *add1 = in(1); 766 int add1_op = add1->Opcode(); 767 if( add1_op == Op_AddL ) { // Left input is an add? 768 // Avoid dead data cycles from dead loops 769 assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" ); 770 const TypeLong *t12 = phase->type(add1->in(2))->isa_long(); 771 if( t12 && t12->is_con() ){ // Left input is an add of a con? 772 // Compute X << con0 773 Node *lsh = phase->transform( new (phase->C) LShiftLNode( add1->in(1), in(2) ) ); 774 // Compute X<<con0 + (con1<<con0) 775 return new (phase->C) AddLNode( lsh, phase->longcon(t12->get_con() << con)); 776 } 777 } 778 779 // Check for "(x>>c0)<<c0" which just masks off low bits 780 if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) && 781 add1->in(2) == in(2) ) 782 // Convert to "(x & -(1<<c0))" 783 return new (phase->C) AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con))); 784 785 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits 786 if( add1_op == Op_AndL ) { 787 Node *add2 = add1->in(1); 788 int add2_op = add2->Opcode(); 789 if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) && 790 add2->in(2) == in(2) ) { 791 // Convert to "(x & (Y<<c0))" 792 Node *y_sh = phase->transform( new (phase->C) LShiftLNode( add1->in(2), in(2) ) ); 793 return new (phase->C) AndLNode( add2->in(1), y_sh ); 794 } 795 } 796 797 // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits 798 // before shifting them away. 799 const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) - CONST64(1); 800 if( add1_op == Op_AndL && 801 phase->type(add1->in(2)) == TypeLong::make( bits_mask ) ) 802 return new (phase->C) LShiftLNode( add1->in(1), in(2) ); 803 804 return NULL; 805 } 806 807 //------------------------------Value------------------------------------------ 808 // A LShiftLNode shifts its input2 left by input1 amount. 809 const Type *LShiftLNode::Value( PhaseTransform *phase ) const { 810 const Type *t1 = phase->type( in(1) ); 811 const Type *t2 = phase->type( in(2) ); 812 // Either input is TOP ==> the result is TOP 813 if( t1 == Type::TOP ) return Type::TOP; 814 if( t2 == Type::TOP ) return Type::TOP; 815 816 // Left input is ZERO ==> the result is ZERO. 817 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 818 // Shift by zero does nothing 819 if( t2 == TypeInt::ZERO ) return t1; 820 821 // Either input is BOTTOM ==> the result is BOTTOM 822 if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) || 823 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 824 return TypeLong::LONG; 825 826 const TypeLong *r1 = t1->is_long(); // Handy access 827 const TypeInt *r2 = t2->is_int(); // Handy access 828 829 if (!r2->is_con()) 830 return TypeLong::LONG; 831 832 uint shift = r2->get_con(); 833 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 834 // Shift by a multiple of 64 does nothing: 835 if (shift == 0) return t1; 836 837 // If the shift is a constant, shift the bounds of the type, 838 // unless this could lead to an overflow. 839 if (!r1->is_con()) { 840 jlong lo = r1->_lo, hi = r1->_hi; 841 if (((lo << shift) >> shift) == lo && 842 ((hi << shift) >> shift) == hi) { 843 // No overflow. The range shifts up cleanly. 844 return TypeLong::make((jlong)lo << (jint)shift, 845 (jlong)hi << (jint)shift, 846 MAX2(r1->_widen,r2->_widen)); 847 } 848 return TypeLong::LONG; 849 } 850 851 return TypeLong::make( (jlong)r1->get_con() << (jint)shift ); 852 } 853 854 //============================================================================= 855 //------------------------------Identity--------------------------------------- 856 Node *RShiftINode::Identity( PhaseTransform *phase ) { 857 const TypeInt *t2 = phase->type(in(2))->isa_int(); 858 if( !t2 ) return this; 859 if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 ) 860 return in(1); 861 862 // Check for useless sign-masking 863 if( in(1)->Opcode() == Op_LShiftI && 864 in(1)->req() == 3 && 865 in(1)->in(2) == in(2) && 866 t2->is_con() ) { 867 uint shift = t2->get_con(); 868 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 869 // Compute masks for which this shifting doesn't change 870 int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000 871 int hi = ~lo; // 00007FFF 872 const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int(); 873 if( !t11 ) return this; 874 // Does actual value fit inside of mask? 875 if( lo <= t11->_lo && t11->_hi <= hi ) 876 return in(1)->in(1); // Then shifting is a nop 877 } 878 879 return this; 880 } 881 882 //------------------------------Ideal------------------------------------------ 883 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 884 // Inputs may be TOP if they are dead. 885 const TypeInt *t1 = phase->type( in(1) )->isa_int(); 886 if( !t1 ) return NULL; // Left input is an integer 887 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 888 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 889 const TypeInt *t3; // type of in(1).in(2) 890 int shift = t2->get_con(); 891 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 892 893 if ( shift == 0 ) return NULL; // let Identity() handle 0 shift count 894 895 // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller. 896 // Such expressions arise normally from shift chains like (byte)(x >> 24). 897 const Node *mask = in(1); 898 if( mask->Opcode() == Op_AndI && 899 (t3 = phase->type(mask->in(2))->isa_int()) && 900 t3->is_con() ) { 901 Node *x = mask->in(1); 902 jint maskbits = t3->get_con(); 903 // Convert to "(x >> shift) & (mask >> shift)" 904 Node *shr_nomask = phase->transform( new (phase->C) RShiftINode(mask->in(1), in(2)) ); 905 return new (phase->C) AndINode(shr_nomask, phase->intcon( maskbits >> shift)); 906 } 907 908 // Check for "(short[i] <<16)>>16" which simply sign-extends 909 const Node *shl = in(1); 910 if( shl->Opcode() != Op_LShiftI ) return NULL; 911 912 if( shift == 16 && 913 (t3 = phase->type(shl->in(2))->isa_int()) && 914 t3->is_con(16) ) { 915 Node *ld = shl->in(1); 916 if( ld->Opcode() == Op_LoadS ) { 917 // Sign extension is just useless here. Return a RShiftI of zero instead 918 // returning 'ld' directly. We cannot return an old Node directly as 919 // that is the job of 'Identity' calls and Identity calls only work on 920 // direct inputs ('ld' is an extra Node removed from 'this'). The 921 // combined optimization requires Identity only return direct inputs. 922 set_req(1, ld); 923 set_req(2, phase->intcon(0)); 924 return this; 925 } 926 else if( ld->Opcode() == Op_LoadUS ) 927 // Replace zero-extension-load with sign-extension-load 928 return new (phase->C) LoadSNode( ld->in(MemNode::Control), 929 ld->in(MemNode::Memory), 930 ld->in(MemNode::Address), 931 ld->adr_type()); 932 } 933 934 // Check for "(byte[i] <<24)>>24" which simply sign-extends 935 if( shift == 24 && 936 (t3 = phase->type(shl->in(2))->isa_int()) && 937 t3->is_con(24) ) { 938 Node *ld = shl->in(1); 939 if( ld->Opcode() == Op_LoadB ) { 940 // Sign extension is just useless here 941 set_req(1, ld); 942 set_req(2, phase->intcon(0)); 943 return this; 944 } 945 } 946 947 return NULL; 948 } 949 950 //------------------------------Value------------------------------------------ 951 // A RShiftINode shifts its input2 right by input1 amount. 952 const Type *RShiftINode::Value( PhaseTransform *phase ) const { 953 const Type *t1 = phase->type( in(1) ); 954 const Type *t2 = phase->type( in(2) ); 955 // Either input is TOP ==> the result is TOP 956 if( t1 == Type::TOP ) return Type::TOP; 957 if( t2 == Type::TOP ) return Type::TOP; 958 959 // Left input is ZERO ==> the result is ZERO. 960 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 961 // Shift by zero does nothing 962 if( t2 == TypeInt::ZERO ) return t1; 963 964 // Either input is BOTTOM ==> the result is BOTTOM 965 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 966 return TypeInt::INT; 967 968 if (t2 == TypeInt::INT) 969 return TypeInt::INT; 970 971 const TypeInt *r1 = t1->is_int(); // Handy access 972 const TypeInt *r2 = t2->is_int(); // Handy access 973 974 // If the shift is a constant, just shift the bounds of the type. 975 // For example, if the shift is 31, we just propagate sign bits. 976 if (r2->is_con()) { 977 uint shift = r2->get_con(); 978 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 979 // Shift by a multiple of 32 does nothing: 980 if (shift == 0) return t1; 981 // Calculate reasonably aggressive bounds for the result. 982 // This is necessary if we are to correctly type things 983 // like (x<<24>>24) == ((byte)x). 984 jint lo = (jint)r1->_lo >> (jint)shift; 985 jint hi = (jint)r1->_hi >> (jint)shift; 986 assert(lo <= hi, "must have valid bounds"); 987 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 988 #ifdef ASSERT 989 // Make sure we get the sign-capture idiom correct. 990 if (shift == BitsPerJavaInteger-1) { 991 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>31 of + is 0"); 992 if (r1->_hi < 0) assert(ti == TypeInt::MINUS_1, ">>31 of - is -1"); 993 } 994 #endif 995 return ti; 996 } 997 998 if( !r1->is_con() || !r2->is_con() ) 999 return TypeInt::INT; 1000 1001 // Signed shift right 1002 return TypeInt::make( r1->get_con() >> (r2->get_con()&31) ); 1003 } 1004 1005 //============================================================================= 1006 //------------------------------Identity--------------------------------------- 1007 Node *RShiftLNode::Identity( PhaseTransform *phase ) { 1008 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 1009 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 1010 } 1011 1012 //------------------------------Value------------------------------------------ 1013 // A RShiftLNode shifts its input2 right by input1 amount. 1014 const Type *RShiftLNode::Value( PhaseTransform *phase ) const { 1015 const Type *t1 = phase->type( in(1) ); 1016 const Type *t2 = phase->type( in(2) ); 1017 // Either input is TOP ==> the result is TOP 1018 if( t1 == Type::TOP ) return Type::TOP; 1019 if( t2 == Type::TOP ) return Type::TOP; 1020 1021 // Left input is ZERO ==> the result is ZERO. 1022 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 1023 // Shift by zero does nothing 1024 if( t2 == TypeInt::ZERO ) return t1; 1025 1026 // Either input is BOTTOM ==> the result is BOTTOM 1027 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1028 return TypeLong::LONG; 1029 1030 if (t2 == TypeInt::INT) 1031 return TypeLong::LONG; 1032 1033 const TypeLong *r1 = t1->is_long(); // Handy access 1034 const TypeInt *r2 = t2->is_int (); // Handy access 1035 1036 // If the shift is a constant, just shift the bounds of the type. 1037 // For example, if the shift is 63, we just propagate sign bits. 1038 if (r2->is_con()) { 1039 uint shift = r2->get_con(); 1040 shift &= (2*BitsPerJavaInteger)-1; // semantics of Java shifts 1041 // Shift by a multiple of 64 does nothing: 1042 if (shift == 0) return t1; 1043 // Calculate reasonably aggressive bounds for the result. 1044 // This is necessary if we are to correctly type things 1045 // like (x<<24>>24) == ((byte)x). 1046 jlong lo = (jlong)r1->_lo >> (jlong)shift; 1047 jlong hi = (jlong)r1->_hi >> (jlong)shift; 1048 assert(lo <= hi, "must have valid bounds"); 1049 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1050 #ifdef ASSERT 1051 // Make sure we get the sign-capture idiom correct. 1052 if (shift == (2*BitsPerJavaInteger)-1) { 1053 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>63 of + is 0"); 1054 if (r1->_hi < 0) assert(tl == TypeLong::MINUS_1, ">>63 of - is -1"); 1055 } 1056 #endif 1057 return tl; 1058 } 1059 1060 return TypeLong::LONG; // Give up 1061 } 1062 1063 //============================================================================= 1064 //------------------------------Identity--------------------------------------- 1065 Node *URShiftINode::Identity( PhaseTransform *phase ) { 1066 const TypeInt *ti = phase->type( in(2) )->isa_int(); 1067 if ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) return in(1); 1068 1069 // Check for "((x << LogBytesPerWord) + (wordSize-1)) >> LogBytesPerWord" which is just "x". 1070 // Happens during new-array length computation. 1071 // Safe if 'x' is in the range [0..(max_int>>LogBytesPerWord)] 1072 Node *add = in(1); 1073 if( add->Opcode() == Op_AddI ) { 1074 const TypeInt *t2 = phase->type(add->in(2))->isa_int(); 1075 if( t2 && t2->is_con(wordSize - 1) && 1076 add->in(1)->Opcode() == Op_LShiftI ) { 1077 // Check that shift_counts are LogBytesPerWord 1078 Node *lshift_count = add->in(1)->in(2); 1079 const TypeInt *t_lshift_count = phase->type(lshift_count)->isa_int(); 1080 if( t_lshift_count && t_lshift_count->is_con(LogBytesPerWord) && 1081 t_lshift_count == phase->type(in(2)) ) { 1082 Node *x = add->in(1)->in(1); 1083 const TypeInt *t_x = phase->type(x)->isa_int(); 1084 if( t_x != NULL && 0 <= t_x->_lo && t_x->_hi <= (max_jint>>LogBytesPerWord) ) { 1085 return x; 1086 } 1087 } 1088 } 1089 } 1090 1091 return (phase->type(in(2))->higher_equal(TypeInt::ZERO)) ? in(1) : this; 1092 } 1093 1094 //------------------------------Ideal------------------------------------------ 1095 Node *URShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 1096 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 1097 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 1098 const int con = t2->get_con() & 31; // Shift count is always masked 1099 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count 1100 // We'll be wanting the right-shift amount as a mask of that many bits 1101 const int mask = right_n_bits(BitsPerJavaInteger - con); 1102 1103 int in1_op = in(1)->Opcode(); 1104 1105 // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32 1106 if( in1_op == Op_URShiftI ) { 1107 const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int(); 1108 if( t12 && t12->is_con() ) { // Right input is a constant 1109 assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" ); 1110 const int con2 = t12->get_con() & 31; // Shift count is always masked 1111 const int con3 = con+con2; 1112 if( con3 < 32 ) // Only merge shifts if total is < 32 1113 return new (phase->C) URShiftINode( in(1)->in(1), phase->intcon(con3) ); 1114 } 1115 } 1116 1117 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z 1118 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z". 1119 // If Q is "X << z" the rounding is useless. Look for patterns like 1120 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask. 1121 Node *add = in(1); 1122 if( in1_op == Op_AddI ) { 1123 Node *lshl = add->in(1); 1124 if( lshl->Opcode() == Op_LShiftI && 1125 phase->type(lshl->in(2)) == t2 ) { 1126 Node *y_z = phase->transform( new (phase->C) URShiftINode(add->in(2),in(2)) ); 1127 Node *sum = phase->transform( new (phase->C) AddINode( lshl->in(1), y_z ) ); 1128 return new (phase->C) AndINode( sum, phase->intcon(mask) ); 1129 } 1130 } 1131 1132 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z) 1133 // This shortens the mask. Also, if we are extracting a high byte and 1134 // storing it to a buffer, the mask will be removed completely. 1135 Node *andi = in(1); 1136 if( in1_op == Op_AndI ) { 1137 const TypeInt *t3 = phase->type( andi->in(2) )->isa_int(); 1138 if( t3 && t3->is_con() ) { // Right input is a constant 1139 jint mask2 = t3->get_con(); 1140 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help) 1141 Node *newshr = phase->transform( new (phase->C) URShiftINode(andi->in(1), in(2)) ); 1142 return new (phase->C) AndINode(newshr, phase->intcon(mask2)); 1143 // The negative values are easier to materialize than positive ones. 1144 // A typical case from address arithmetic is ((x & ~15) >> 4). 1145 // It's better to change that to ((x >> 4) & ~0) versus 1146 // ((x >> 4) & 0x0FFFFFFF). The difference is greatest in LP64. 1147 } 1148 } 1149 1150 // Check for "(X << z ) >>> z" which simply zero-extends 1151 Node *shl = in(1); 1152 if( in1_op == Op_LShiftI && 1153 phase->type(shl->in(2)) == t2 ) 1154 return new (phase->C) AndINode( shl->in(1), phase->intcon(mask) ); 1155 1156 return NULL; 1157 } 1158 1159 //------------------------------Value------------------------------------------ 1160 // A URShiftINode shifts its input2 right by input1 amount. 1161 const Type *URShiftINode::Value( PhaseTransform *phase ) const { 1162 // (This is a near clone of RShiftINode::Value.) 1163 const Type *t1 = phase->type( in(1) ); 1164 const Type *t2 = phase->type( in(2) ); 1165 // Either input is TOP ==> the result is TOP 1166 if( t1 == Type::TOP ) return Type::TOP; 1167 if( t2 == Type::TOP ) return Type::TOP; 1168 1169 // Left input is ZERO ==> the result is ZERO. 1170 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 1171 // Shift by zero does nothing 1172 if( t2 == TypeInt::ZERO ) return t1; 1173 1174 // Either input is BOTTOM ==> the result is BOTTOM 1175 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1176 return TypeInt::INT; 1177 1178 if (t2 == TypeInt::INT) 1179 return TypeInt::INT; 1180 1181 const TypeInt *r1 = t1->is_int(); // Handy access 1182 const TypeInt *r2 = t2->is_int(); // Handy access 1183 1184 if (r2->is_con()) { 1185 uint shift = r2->get_con(); 1186 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 1187 // Shift by a multiple of 32 does nothing: 1188 if (shift == 0) return t1; 1189 // Calculate reasonably aggressive bounds for the result. 1190 jint lo = (juint)r1->_lo >> (juint)shift; 1191 jint hi = (juint)r1->_hi >> (juint)shift; 1192 if (r1->_hi >= 0 && r1->_lo < 0) { 1193 // If the type has both negative and positive values, 1194 // there are two separate sub-domains to worry about: 1195 // The positive half and the negative half. 1196 jint neg_lo = lo; 1197 jint neg_hi = (juint)-1 >> (juint)shift; 1198 jint pos_lo = (juint) 0 >> (juint)shift; 1199 jint pos_hi = hi; 1200 lo = MIN2(neg_lo, pos_lo); // == 0 1201 hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift; 1202 } 1203 assert(lo <= hi, "must have valid bounds"); 1204 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1205 #ifdef ASSERT 1206 // Make sure we get the sign-capture idiom correct. 1207 if (shift == BitsPerJavaInteger-1) { 1208 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0"); 1209 if (r1->_hi < 0) assert(ti == TypeInt::ONE, ">>>31 of - is +1"); 1210 } 1211 #endif 1212 return ti; 1213 } 1214 1215 // 1216 // Do not support shifted oops in info for GC 1217 // 1218 // else if( t1->base() == Type::InstPtr ) { 1219 // 1220 // const TypeInstPtr *o = t1->is_instptr(); 1221 // if( t1->singleton() ) 1222 // return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift ); 1223 // } 1224 // else if( t1->base() == Type::KlassPtr ) { 1225 // const TypeKlassPtr *o = t1->is_klassptr(); 1226 // if( t1->singleton() ) 1227 // return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift ); 1228 // } 1229 1230 return TypeInt::INT; 1231 } 1232 1233 //============================================================================= 1234 //------------------------------Identity--------------------------------------- 1235 Node *URShiftLNode::Identity( PhaseTransform *phase ) { 1236 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 1237 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 1238 } 1239 1240 //------------------------------Ideal------------------------------------------ 1241 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1242 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 1243 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 1244 const int con = t2->get_con() & ( BitsPerLong - 1 ); // Shift count is always masked 1245 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count 1246 // note: mask computation below does not work for 0 shift count 1247 // We'll be wanting the right-shift amount as a mask of that many bits 1248 const jlong mask = (((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) -1); 1249 1250 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z 1251 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z". 1252 // If Q is "X << z" the rounding is useless. Look for patterns like 1253 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask. 1254 Node *add = in(1); 1255 if( add->Opcode() == Op_AddL ) { 1256 Node *lshl = add->in(1); 1257 if( lshl->Opcode() == Op_LShiftL && 1258 phase->type(lshl->in(2)) == t2 ) { 1259 Node *y_z = phase->transform( new (phase->C) URShiftLNode(add->in(2),in(2)) ); 1260 Node *sum = phase->transform( new (phase->C) AddLNode( lshl->in(1), y_z ) ); 1261 return new (phase->C) AndLNode( sum, phase->longcon(mask) ); 1262 } 1263 } 1264 1265 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z) 1266 // This shortens the mask. Also, if we are extracting a high byte and 1267 // storing it to a buffer, the mask will be removed completely. 1268 Node *andi = in(1); 1269 if( andi->Opcode() == Op_AndL ) { 1270 const TypeLong *t3 = phase->type( andi->in(2) )->isa_long(); 1271 if( t3 && t3->is_con() ) { // Right input is a constant 1272 jlong mask2 = t3->get_con(); 1273 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help) 1274 Node *newshr = phase->transform( new (phase->C) URShiftLNode(andi->in(1), in(2)) ); 1275 return new (phase->C) AndLNode(newshr, phase->longcon(mask2)); 1276 } 1277 } 1278 1279 // Check for "(X << z ) >>> z" which simply zero-extends 1280 Node *shl = in(1); 1281 if( shl->Opcode() == Op_LShiftL && 1282 phase->type(shl->in(2)) == t2 ) 1283 return new (phase->C) AndLNode( shl->in(1), phase->longcon(mask) ); 1284 1285 return NULL; 1286 } 1287 1288 //------------------------------Value------------------------------------------ 1289 // A URShiftINode shifts its input2 right by input1 amount. 1290 const Type *URShiftLNode::Value( PhaseTransform *phase ) const { 1291 // (This is a near clone of RShiftLNode::Value.) 1292 const Type *t1 = phase->type( in(1) ); 1293 const Type *t2 = phase->type( in(2) ); 1294 // Either input is TOP ==> the result is TOP 1295 if( t1 == Type::TOP ) return Type::TOP; 1296 if( t2 == Type::TOP ) return Type::TOP; 1297 1298 // Left input is ZERO ==> the result is ZERO. 1299 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 1300 // Shift by zero does nothing 1301 if( t2 == TypeInt::ZERO ) return t1; 1302 1303 // Either input is BOTTOM ==> the result is BOTTOM 1304 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1305 return TypeLong::LONG; 1306 1307 if (t2 == TypeInt::INT) 1308 return TypeLong::LONG; 1309 1310 const TypeLong *r1 = t1->is_long(); // Handy access 1311 const TypeInt *r2 = t2->is_int (); // Handy access 1312 1313 if (r2->is_con()) { 1314 uint shift = r2->get_con(); 1315 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 1316 // Shift by a multiple of 64 does nothing: 1317 if (shift == 0) return t1; 1318 // Calculate reasonably aggressive bounds for the result. 1319 jlong lo = (julong)r1->_lo >> (juint)shift; 1320 jlong hi = (julong)r1->_hi >> (juint)shift; 1321 if (r1->_hi >= 0 && r1->_lo < 0) { 1322 // If the type has both negative and positive values, 1323 // there are two separate sub-domains to worry about: 1324 // The positive half and the negative half. 1325 jlong neg_lo = lo; 1326 jlong neg_hi = (julong)-1 >> (juint)shift; 1327 jlong pos_lo = (julong) 0 >> (juint)shift; 1328 jlong pos_hi = hi; 1329 //lo = MIN2(neg_lo, pos_lo); // == 0 1330 lo = neg_lo < pos_lo ? neg_lo : pos_lo; 1331 //hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift; 1332 hi = neg_hi > pos_hi ? neg_hi : pos_hi; 1333 } 1334 assert(lo <= hi, "must have valid bounds"); 1335 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1336 #ifdef ASSERT 1337 // Make sure we get the sign-capture idiom correct. 1338 if (shift == BitsPerJavaLong - 1) { 1339 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0"); 1340 if (r1->_hi < 0) assert(tl == TypeLong::ONE, ">>>63 of - is +1"); 1341 } 1342 #endif 1343 return tl; 1344 } 1345 1346 return TypeLong::LONG; // Give up 1347 }