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/convertnode.hpp" 30 #include "opto/memnode.hpp" 31 #include "opto/mulnode.hpp" 32 #include "opto/phaseX.hpp" 33 #include "opto/subnode.hpp" 34 35 // Portions of code courtesy of Clifford Click 36 37 38 //============================================================================= 39 //------------------------------hash------------------------------------------- 40 // Hash function over MulNodes. Needs to be commutative; i.e., I swap 41 // (commute) inputs to MulNodes willy-nilly so the hash function must return 42 // the same value in the presence of edge swapping. 43 uint MulNode::hash() const { 44 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode(); 45 } 46 47 //------------------------------Identity--------------------------------------- 48 // Multiplying a one preserves the other argument 49 Node* MulNode::Identity(PhaseGVN* phase) { 50 register const Type *one = mul_id(); // The multiplicative identity 51 if( phase->type( in(1) )->higher_equal( one ) ) return in(2); 52 if( phase->type( in(2) )->higher_equal( one ) ) return in(1); 53 54 return this; 55 } 56 57 //------------------------------Ideal------------------------------------------ 58 // We also canonicalize the Node, moving constants to the right input, 59 // and flatten expressions (so that 1+x+2 becomes x+3). 60 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) { 61 const Type *t1 = phase->type( in(1) ); 62 const Type *t2 = phase->type( in(2) ); 63 Node *progress = NULL; // Progress flag 64 // We are OK if right is a constant, or right is a load and 65 // left is a non-constant. 66 if( !(t2->singleton() || 67 (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) { 68 if( t1->singleton() || // Left input is a constant? 69 // Otherwise, sort inputs (commutativity) to help value numbering. 70 (in(1)->_idx > in(2)->_idx) ) { 71 swap_edges(1, 2); 72 const Type *t = t1; 73 t1 = t2; 74 t2 = t; 75 progress = this; // Made progress 76 } 77 } 78 79 // If the right input is a constant, and the left input is a product of a 80 // constant, flatten the expression tree. 81 uint op = Opcode(); 82 if( t2->singleton() && // Right input is a constant? 83 op != Op_MulF && // Float & double cannot reassociate 84 op != Op_MulD ) { 85 if( t2 == Type::TOP ) return NULL; 86 Node *mul1 = in(1); 87 #ifdef ASSERT 88 // Check for dead loop 89 int op1 = mul1->Opcode(); 90 if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) || 91 ( op1 == mul_opcode() || op1 == add_opcode() ) && 92 ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) || 93 phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) ) 94 assert(false, "dead loop in MulNode::Ideal"); 95 #endif 96 97 if( mul1->Opcode() == mul_opcode() ) { // Left input is a multiply? 98 // Mul of a constant? 99 const Type *t12 = phase->type( mul1->in(2) ); 100 if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant? 101 // Compute new constant; check for overflow 102 const Type *tcon01 = ((MulNode*)mul1)->mul_ring(t2,t12); 103 if( tcon01->singleton() ) { 104 // The Mul of the flattened expression 105 set_req(1, mul1->in(1)); 106 set_req(2, phase->makecon( tcon01 )); 107 t2 = tcon01; 108 progress = this; // Made progress 109 } 110 } 111 } 112 // If the right input is a constant, and the left input is an add of a 113 // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0 114 const Node *add1 = in(1); 115 if( add1->Opcode() == add_opcode() ) { // Left input is an add? 116 // Add of a constant? 117 const Type *t12 = phase->type( add1->in(2) ); 118 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant? 119 assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" ); 120 // Compute new constant; check for overflow 121 const Type *tcon01 = mul_ring(t2,t12); 122 if( tcon01->singleton() ) { 123 124 // Convert (X+con1)*con0 into X*con0 125 Node *mul = clone(); // mul = ()*con0 126 mul->set_req(1,add1->in(1)); // mul = X*con0 127 mul = phase->transform(mul); 128 129 Node *add2 = add1->clone(); 130 add2->set_req(1, mul); // X*con0 + con0*con1 131 add2->set_req(2, phase->makecon(tcon01) ); 132 progress = add2; 133 } 134 } 135 } // End of is left input an add 136 } // End of is right input a Mul 137 138 return progress; 139 } 140 141 //------------------------------Value----------------------------------------- 142 const Type* MulNode::Value(PhaseGVN* phase) const { 143 const Type *t1 = phase->type( in(1) ); 144 const Type *t2 = phase->type( in(2) ); 145 // Either input is TOP ==> the result is TOP 146 if( t1 == Type::TOP ) return Type::TOP; 147 if( t2 == Type::TOP ) return Type::TOP; 148 149 // Either input is ZERO ==> the result is ZERO. 150 // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0 151 int op = Opcode(); 152 if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) { 153 const Type *zero = add_id(); // The multiplicative zero 154 if( t1->higher_equal( zero ) ) return zero; 155 if( t2->higher_equal( zero ) ) return zero; 156 } 157 158 // Either input is BOTTOM ==> the result is the local BOTTOM 159 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM ) 160 return bottom_type(); 161 162 #if defined(IA32) 163 // Can't trust native compilers to properly fold strict double 164 // multiplication with round-to-zero on this platform. 165 if (op == Op_MulD && phase->C->method()->is_strict()) { 166 return TypeD::DOUBLE; 167 } 168 #endif 169 170 return mul_ring(t1,t2); // Local flavor of type multiplication 171 } 172 173 174 //============================================================================= 175 //------------------------------Ideal------------------------------------------ 176 // Check for power-of-2 multiply, then try the regular MulNode::Ideal 177 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) { 178 // Swap constant to right 179 jint con; 180 if ((con = in(1)->find_int_con(0)) != 0) { 181 swap_edges(1, 2); 182 // Finish rest of method to use info in 'con' 183 } else if ((con = in(2)->find_int_con(0)) == 0) { 184 return MulNode::Ideal(phase, can_reshape); 185 } 186 187 // Now we have a constant Node on the right and the constant in con 188 if( con == 0 ) return NULL; // By zero is handled by Value call 189 if( con == 1 ) return NULL; // By one is handled by Identity call 190 191 // Check for negative constant; if so negate the final result 192 bool sign_flip = false; 193 if( con < 0 ) { 194 con = -con; 195 sign_flip = true; 196 } 197 198 // Get low bit; check for being the only bit 199 Node *res = NULL; 200 jint bit1 = con & -con; // Extract low bit 201 if( bit1 == con ) { // Found a power of 2? 202 res = new LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ); 203 } else { 204 205 // Check for constant with 2 bits set 206 jint bit2 = con-bit1; 207 bit2 = bit2 & -bit2; // Extract 2nd bit 208 if( bit2 + bit1 == con ) { // Found all bits in con? 209 Node *n1 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) ); 210 Node *n2 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) ); 211 res = new AddINode( n2, n1 ); 212 213 } else if (is_power_of_2(con+1)) { 214 // Sleezy: power-of-2 -1. Next time be generic. 215 jint temp = (jint) (con + 1); 216 Node *n1 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) ); 217 res = new SubINode( n1, in(1) ); 218 } else { 219 return MulNode::Ideal(phase, can_reshape); 220 } 221 } 222 223 if( sign_flip ) { // Need to negate result? 224 res = phase->transform(res);// Transform, before making the zero con 225 res = new SubINode(phase->intcon(0),res); 226 } 227 228 return res; // Return final result 229 } 230 231 //------------------------------mul_ring--------------------------------------- 232 // Compute the product type of two integer ranges into this node. 233 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const { 234 const TypeInt *r0 = t0->is_int(); // Handy access 235 const TypeInt *r1 = t1->is_int(); 236 237 // Fetch endpoints of all ranges 238 int32_t lo0 = r0->_lo; 239 double a = (double)lo0; 240 int32_t hi0 = r0->_hi; 241 double b = (double)hi0; 242 int32_t lo1 = r1->_lo; 243 double c = (double)lo1; 244 int32_t hi1 = r1->_hi; 245 double d = (double)hi1; 246 247 // Compute all endpoints & check for overflow 248 int32_t A = java_multiply(lo0, lo1); 249 if( (double)A != a*c ) return TypeInt::INT; // Overflow? 250 int32_t B = java_multiply(lo0, hi1); 251 if( (double)B != a*d ) return TypeInt::INT; // Overflow? 252 int32_t C = java_multiply(hi0, lo1); 253 if( (double)C != b*c ) return TypeInt::INT; // Overflow? 254 int32_t D = java_multiply(hi0, hi1); 255 if( (double)D != b*d ) return TypeInt::INT; // Overflow? 256 257 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints 258 else { lo0 = B; hi0 = A; } 259 if( C < D ) { 260 if( C < lo0 ) lo0 = C; 261 if( D > hi0 ) hi0 = D; 262 } else { 263 if( D < lo0 ) lo0 = D; 264 if( C > hi0 ) hi0 = C; 265 } 266 return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen)); 267 } 268 269 270 //============================================================================= 271 //------------------------------Ideal------------------------------------------ 272 // Check for power-of-2 multiply, then try the regular MulNode::Ideal 273 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 274 // Swap constant to right 275 jlong con; 276 if ((con = in(1)->find_long_con(0)) != 0) { 277 swap_edges(1, 2); 278 // Finish rest of method to use info in 'con' 279 } else if ((con = in(2)->find_long_con(0)) == 0) { 280 return MulNode::Ideal(phase, can_reshape); 281 } 282 283 // Now we have a constant Node on the right and the constant in con 284 if( con == CONST64(0) ) return NULL; // By zero is handled by Value call 285 if( con == CONST64(1) ) return NULL; // By one is handled by Identity call 286 287 // Check for negative constant; if so negate the final result 288 bool sign_flip = false; 289 if( con < 0 ) { 290 con = -con; 291 sign_flip = true; 292 } 293 294 // Get low bit; check for being the only bit 295 Node *res = NULL; 296 jlong bit1 = con & -con; // Extract low bit 297 if( bit1 == con ) { // Found a power of 2? 298 res = new LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ); 299 } else { 300 301 // Check for constant with 2 bits set 302 jlong bit2 = con-bit1; 303 bit2 = bit2 & -bit2; // Extract 2nd bit 304 if( bit2 + bit1 == con ) { // Found all bits in con? 305 Node *n1 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) ); 306 Node *n2 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) ); 307 res = new AddLNode( n2, n1 ); 308 309 } else if (is_power_of_2_long(con+1)) { 310 // Sleezy: power-of-2 -1. Next time be generic. 311 jlong temp = (jlong) (con + 1); 312 Node *n1 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) ); 313 res = new SubLNode( n1, in(1) ); 314 } else { 315 return MulNode::Ideal(phase, can_reshape); 316 } 317 } 318 319 if( sign_flip ) { // Need to negate result? 320 res = phase->transform(res);// Transform, before making the zero con 321 res = new SubLNode(phase->longcon(0),res); 322 } 323 324 return res; // Return final result 325 } 326 327 //------------------------------mul_ring--------------------------------------- 328 // Compute the product type of two integer ranges into this node. 329 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const { 330 const TypeLong *r0 = t0->is_long(); // Handy access 331 const TypeLong *r1 = t1->is_long(); 332 333 // Fetch endpoints of all ranges 334 jlong lo0 = r0->_lo; 335 double a = (double)lo0; 336 jlong hi0 = r0->_hi; 337 double b = (double)hi0; 338 jlong lo1 = r1->_lo; 339 double c = (double)lo1; 340 jlong hi1 = r1->_hi; 341 double d = (double)hi1; 342 343 // Compute all endpoints & check for overflow 344 jlong A = java_multiply(lo0, lo1); 345 if( (double)A != a*c ) return TypeLong::LONG; // Overflow? 346 jlong B = java_multiply(lo0, hi1); 347 if( (double)B != a*d ) return TypeLong::LONG; // Overflow? 348 jlong C = java_multiply(hi0, lo1); 349 if( (double)C != b*c ) return TypeLong::LONG; // Overflow? 350 jlong D = java_multiply(hi0, hi1); 351 if( (double)D != b*d ) return TypeLong::LONG; // Overflow? 352 353 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints 354 else { lo0 = B; hi0 = A; } 355 if( C < D ) { 356 if( C < lo0 ) lo0 = C; 357 if( D > hi0 ) hi0 = D; 358 } else { 359 if( D < lo0 ) lo0 = D; 360 if( C > hi0 ) hi0 = C; 361 } 362 return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen)); 363 } 364 365 //============================================================================= 366 //------------------------------mul_ring--------------------------------------- 367 // Compute the product type of two double ranges into this node. 368 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const { 369 if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT; 370 return TypeF::make( t0->getf() * t1->getf() ); 371 } 372 373 //============================================================================= 374 //------------------------------mul_ring--------------------------------------- 375 // Compute the product type of two double ranges into this node. 376 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const { 377 if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE; 378 // We must be multiplying 2 double constants. 379 return TypeD::make( t0->getd() * t1->getd() ); 380 } 381 382 //============================================================================= 383 //------------------------------Value------------------------------------------ 384 const Type* MulHiLNode::Value(PhaseGVN* phase) const { 385 // Either input is TOP ==> the result is TOP 386 const Type *t1 = phase->type( in(1) ); 387 const Type *t2 = phase->type( in(2) ); 388 if( t1 == Type::TOP ) return Type::TOP; 389 if( t2 == Type::TOP ) return Type::TOP; 390 391 // Either input is BOTTOM ==> the result is the local BOTTOM 392 const Type *bot = bottom_type(); 393 if( (t1 == bot) || (t2 == bot) || 394 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 395 return bot; 396 397 // It is not worth trying to constant fold this stuff! 398 return TypeLong::LONG; 399 } 400 401 //============================================================================= 402 //------------------------------mul_ring--------------------------------------- 403 // Supplied function returns the product of the inputs IN THE CURRENT RING. 404 // For the logical operations the ring's MUL is really a logical AND function. 405 // This also type-checks the inputs for sanity. Guaranteed never to 406 // be passed a TOP or BOTTOM type, these are filtered out by pre-check. 407 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const { 408 const TypeInt *r0 = t0->is_int(); // Handy access 409 const TypeInt *r1 = t1->is_int(); 410 int widen = MAX2(r0->_widen,r1->_widen); 411 412 // If either input is a constant, might be able to trim cases 413 if( !r0->is_con() && !r1->is_con() ) 414 return TypeInt::INT; // No constants to be had 415 416 // Both constants? Return bits 417 if( r0->is_con() && r1->is_con() ) 418 return TypeInt::make( r0->get_con() & r1->get_con() ); 419 420 if( r0->is_con() && r0->get_con() > 0 ) 421 return TypeInt::make(0, r0->get_con(), widen); 422 423 if( r1->is_con() && r1->get_con() > 0 ) 424 return TypeInt::make(0, r1->get_con(), widen); 425 426 if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) { 427 return TypeInt::BOOL; 428 } 429 430 return TypeInt::INT; // No constants to be had 431 } 432 433 //------------------------------Identity--------------------------------------- 434 // Masking off the high bits of an unsigned load is not required 435 Node* AndINode::Identity(PhaseGVN* phase) { 436 437 // x & x => x 438 if (phase->eqv(in(1), in(2))) return in(1); 439 440 Node* in1 = in(1); 441 uint op = in1->Opcode(); 442 const TypeInt* t2 = phase->type(in(2))->isa_int(); 443 if (t2 && t2->is_con()) { 444 int con = t2->get_con(); 445 // Masking off high bits which are always zero is useless. 446 const TypeInt* t1 = phase->type( in(1) )->isa_int(); 447 if (t1 != NULL && t1->_lo >= 0) { 448 jint t1_support = right_n_bits(1 + log2_intptr(t1->_hi)); 449 if ((t1_support & con) == t1_support) 450 return in1; 451 } 452 // Masking off the high bits of a unsigned-shift-right is not 453 // needed either. 454 if (op == Op_URShiftI) { 455 const TypeInt* t12 = phase->type(in1->in(2))->isa_int(); 456 if (t12 && t12->is_con()) { // Shift is by a constant 457 int shift = t12->get_con(); 458 shift &= BitsPerJavaInteger - 1; // semantics of Java shifts 459 int mask = max_juint >> shift; 460 if ((mask & con) == mask) // If AND is useless, skip it 461 return in1; 462 } 463 } 464 } 465 return MulNode::Identity(phase); 466 } 467 468 //------------------------------Ideal------------------------------------------ 469 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) { 470 // Special case constant AND mask 471 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 472 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape); 473 const int mask = t2->get_con(); 474 Node *load = in(1); 475 uint lop = load->Opcode(); 476 477 // Masking bits off of a Character? Hi bits are already zero. 478 if( lop == Op_LoadUS && 479 (mask & 0xFFFF0000) ) // Can we make a smaller mask? 480 return new AndINode(load,phase->intcon(mask&0xFFFF)); 481 482 // Masking bits off of a Short? Loading a Character does some masking 483 if (can_reshape && 484 load->outcnt() == 1 && load->unique_out() == this) { 485 if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) { 486 Node *ldus = new LoadUSNode(load->in(MemNode::Control), 487 load->in(MemNode::Memory), 488 load->in(MemNode::Address), 489 load->adr_type(), 490 TypeInt::CHAR, MemNode::unordered); 491 ldus = phase->transform(ldus); 492 return new AndINode(ldus, phase->intcon(mask & 0xFFFF)); 493 } 494 495 // Masking sign bits off of a Byte? Do an unsigned byte load plus 496 // an and. 497 if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) { 498 Node* ldub = new LoadUBNode(load->in(MemNode::Control), 499 load->in(MemNode::Memory), 500 load->in(MemNode::Address), 501 load->adr_type(), 502 TypeInt::UBYTE, MemNode::unordered); 503 ldub = phase->transform(ldub); 504 return new AndINode(ldub, phase->intcon(mask)); 505 } 506 } 507 508 // Masking off sign bits? Dont make them! 509 if( lop == Op_RShiftI ) { 510 const TypeInt *t12 = phase->type(load->in(2))->isa_int(); 511 if( t12 && t12->is_con() ) { // Shift is by a constant 512 int shift = t12->get_con(); 513 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 514 const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift); 515 // If the AND'ing of the 2 masks has no bits, then only original shifted 516 // bits survive. NO sign-extension bits survive the maskings. 517 if( (sign_bits_mask & mask) == 0 ) { 518 // Use zero-fill shift instead 519 Node *zshift = phase->transform(new URShiftINode(load->in(1),load->in(2))); 520 return new AndINode( zshift, in(2) ); 521 } 522 } 523 } 524 525 // Check for 'negate/and-1', a pattern emitted when someone asks for 526 // 'mod 2'. Negate leaves the low order bit unchanged (think: complement 527 // plus 1) and the mask is of the low order bit. Skip the negate. 528 if( lop == Op_SubI && mask == 1 && load->in(1) && 529 phase->type(load->in(1)) == TypeInt::ZERO ) 530 return new AndINode( load->in(2), in(2) ); 531 532 return MulNode::Ideal(phase, can_reshape); 533 } 534 535 //============================================================================= 536 //------------------------------mul_ring--------------------------------------- 537 // Supplied function returns the product of the inputs IN THE CURRENT RING. 538 // For the logical operations the ring's MUL is really a logical AND function. 539 // This also type-checks the inputs for sanity. Guaranteed never to 540 // be passed a TOP or BOTTOM type, these are filtered out by pre-check. 541 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const { 542 const TypeLong *r0 = t0->is_long(); // Handy access 543 const TypeLong *r1 = t1->is_long(); 544 int widen = MAX2(r0->_widen,r1->_widen); 545 546 // If either input is a constant, might be able to trim cases 547 if( !r0->is_con() && !r1->is_con() ) 548 return TypeLong::LONG; // No constants to be had 549 550 // Both constants? Return bits 551 if( r0->is_con() && r1->is_con() ) 552 return TypeLong::make( r0->get_con() & r1->get_con() ); 553 554 if( r0->is_con() && r0->get_con() > 0 ) 555 return TypeLong::make(CONST64(0), r0->get_con(), widen); 556 557 if( r1->is_con() && r1->get_con() > 0 ) 558 return TypeLong::make(CONST64(0), r1->get_con(), widen); 559 560 return TypeLong::LONG; // No constants to be had 561 } 562 563 //------------------------------Identity--------------------------------------- 564 // Masking off the high bits of an unsigned load is not required 565 Node* AndLNode::Identity(PhaseGVN* phase) { 566 567 // x & x => x 568 if (phase->eqv(in(1), in(2))) return in(1); 569 570 Node *usr = in(1); 571 const TypeLong *t2 = phase->type( in(2) )->isa_long(); 572 if( t2 && t2->is_con() ) { 573 jlong con = t2->get_con(); 574 // Masking off high bits which are always zero is useless. 575 const TypeLong* t1 = phase->type( in(1) )->isa_long(); 576 if (t1 != NULL && t1->_lo >= 0) { 577 int bit_count = log2_long(t1->_hi) + 1; 578 jlong t1_support = jlong(max_julong >> (BitsPerJavaLong - bit_count)); 579 if ((t1_support & con) == t1_support) 580 return usr; 581 } 582 uint lop = usr->Opcode(); 583 // Masking off the high bits of a unsigned-shift-right is not 584 // needed either. 585 if( lop == Op_URShiftL ) { 586 const TypeInt *t12 = phase->type( usr->in(2) )->isa_int(); 587 if( t12 && t12->is_con() ) { // Shift is by a constant 588 int shift = t12->get_con(); 589 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 590 jlong mask = max_julong >> shift; 591 if( (mask&con) == mask ) // If AND is useless, skip it 592 return usr; 593 } 594 } 595 } 596 return MulNode::Identity(phase); 597 } 598 599 //------------------------------Ideal------------------------------------------ 600 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 601 // Special case constant AND mask 602 const TypeLong *t2 = phase->type( in(2) )->isa_long(); 603 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape); 604 const jlong mask = t2->get_con(); 605 606 Node* in1 = in(1); 607 uint op = in1->Opcode(); 608 609 // Are we masking a long that was converted from an int with a mask 610 // that fits in 32-bits? Commute them and use an AndINode. Don't 611 // convert masks which would cause a sign extension of the integer 612 // value. This check includes UI2L masks (0x00000000FFFFFFFF) which 613 // would be optimized away later in Identity. 614 if (op == Op_ConvI2L && (mask & UCONST64(0xFFFFFFFF80000000)) == 0) { 615 Node* andi = new AndINode(in1->in(1), phase->intcon(mask)); 616 andi = phase->transform(andi); 617 return new ConvI2LNode(andi); 618 } 619 620 // Masking off sign bits? Dont make them! 621 if (op == Op_RShiftL) { 622 const TypeInt* t12 = phase->type(in1->in(2))->isa_int(); 623 if( t12 && t12->is_con() ) { // Shift is by a constant 624 int shift = t12->get_con(); 625 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 626 const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1); 627 // If the AND'ing of the 2 masks has no bits, then only original shifted 628 // bits survive. NO sign-extension bits survive the maskings. 629 if( (sign_bits_mask & mask) == 0 ) { 630 // Use zero-fill shift instead 631 Node *zshift = phase->transform(new URShiftLNode(in1->in(1), in1->in(2))); 632 return new AndLNode(zshift, in(2)); 633 } 634 } 635 } 636 637 return MulNode::Ideal(phase, can_reshape); 638 } 639 640 //============================================================================= 641 //------------------------------Identity--------------------------------------- 642 Node* LShiftINode::Identity(PhaseGVN* phase) { 643 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 644 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this; 645 } 646 647 //------------------------------Ideal------------------------------------------ 648 // If the right input is a constant, and the left input is an add of a 649 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0 650 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 651 const Type *t = phase->type( in(2) ); 652 if( t == Type::TOP ) return NULL; // Right input is dead 653 const TypeInt *t2 = t->isa_int(); 654 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 655 const int con = t2->get_con() & ( BitsPerInt - 1 ); // masked shift count 656 657 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count 658 659 // Left input is an add of a constant? 660 Node *add1 = in(1); 661 int add1_op = add1->Opcode(); 662 if( add1_op == Op_AddI ) { // Left input is an add? 663 assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" ); 664 const TypeInt *t12 = phase->type(add1->in(2))->isa_int(); 665 if( t12 && t12->is_con() ){ // Left input is an add of a con? 666 // Transform is legal, but check for profit. Avoid breaking 'i2s' 667 // and 'i2b' patterns which typically fold into 'StoreC/StoreB'. 668 if( con < 16 ) { 669 // Compute X << con0 670 Node *lsh = phase->transform( new LShiftINode( add1->in(1), in(2) ) ); 671 // Compute X<<con0 + (con1<<con0) 672 return new AddINode( lsh, phase->intcon(t12->get_con() << con)); 673 } 674 } 675 } 676 677 // Check for "(x>>c0)<<c0" which just masks off low bits 678 if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) && 679 add1->in(2) == in(2) ) 680 // Convert to "(x & -(1<<c0))" 681 return new AndINode(add1->in(1),phase->intcon( -(1<<con))); 682 683 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits 684 if( add1_op == Op_AndI ) { 685 Node *add2 = add1->in(1); 686 int add2_op = add2->Opcode(); 687 if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) && 688 add2->in(2) == in(2) ) { 689 // Convert to "(x & (Y<<c0))" 690 Node *y_sh = phase->transform( new LShiftINode( add1->in(2), in(2) ) ); 691 return new AndINode( add2->in(1), y_sh ); 692 } 693 } 694 695 // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits 696 // before shifting them away. 697 const jint bits_mask = right_n_bits(BitsPerJavaInteger-con); 698 if( add1_op == Op_AndI && 699 phase->type(add1->in(2)) == TypeInt::make( bits_mask ) ) 700 return new LShiftINode( add1->in(1), in(2) ); 701 702 return NULL; 703 } 704 705 //------------------------------Value------------------------------------------ 706 // A LShiftINode shifts its input2 left by input1 amount. 707 const Type* LShiftINode::Value(PhaseGVN* phase) const { 708 const Type *t1 = phase->type( in(1) ); 709 const Type *t2 = phase->type( in(2) ); 710 // Either input is TOP ==> the result is TOP 711 if( t1 == Type::TOP ) return Type::TOP; 712 if( t2 == Type::TOP ) return Type::TOP; 713 714 // Left input is ZERO ==> the result is ZERO. 715 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 716 // Shift by zero does nothing 717 if( t2 == TypeInt::ZERO ) return t1; 718 719 // Either input is BOTTOM ==> the result is BOTTOM 720 if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) || 721 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 722 return TypeInt::INT; 723 724 const TypeInt *r1 = t1->is_int(); // Handy access 725 const TypeInt *r2 = t2->is_int(); // Handy access 726 727 if (!r2->is_con()) 728 return TypeInt::INT; 729 730 uint shift = r2->get_con(); 731 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 732 // Shift by a multiple of 32 does nothing: 733 if (shift == 0) return t1; 734 735 // If the shift is a constant, shift the bounds of the type, 736 // unless this could lead to an overflow. 737 if (!r1->is_con()) { 738 jint lo = r1->_lo, hi = r1->_hi; 739 if (((lo << shift) >> shift) == lo && 740 ((hi << shift) >> shift) == hi) { 741 // No overflow. The range shifts up cleanly. 742 return TypeInt::make((jint)lo << (jint)shift, 743 (jint)hi << (jint)shift, 744 MAX2(r1->_widen,r2->_widen)); 745 } 746 return TypeInt::INT; 747 } 748 749 return TypeInt::make( (jint)r1->get_con() << (jint)shift ); 750 } 751 752 //============================================================================= 753 //------------------------------Identity--------------------------------------- 754 Node* LShiftLNode::Identity(PhaseGVN* phase) { 755 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 756 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 757 } 758 759 //------------------------------Ideal------------------------------------------ 760 // If the right input is a constant, and the left input is an add of a 761 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0 762 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 763 const Type *t = phase->type( in(2) ); 764 if( t == Type::TOP ) return NULL; // Right input is dead 765 const TypeInt *t2 = t->isa_int(); 766 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 767 const int con = t2->get_con() & ( BitsPerLong - 1 ); // masked shift count 768 769 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count 770 771 // Left input is an add of a constant? 772 Node *add1 = in(1); 773 int add1_op = add1->Opcode(); 774 if( add1_op == Op_AddL ) { // Left input is an add? 775 // Avoid dead data cycles from dead loops 776 assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" ); 777 const TypeLong *t12 = phase->type(add1->in(2))->isa_long(); 778 if( t12 && t12->is_con() ){ // Left input is an add of a con? 779 // Compute X << con0 780 Node *lsh = phase->transform( new LShiftLNode( add1->in(1), in(2) ) ); 781 // Compute X<<con0 + (con1<<con0) 782 return new AddLNode( lsh, phase->longcon(t12->get_con() << con)); 783 } 784 } 785 786 // Check for "(x>>c0)<<c0" which just masks off low bits 787 if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) && 788 add1->in(2) == in(2) ) 789 // Convert to "(x & -(1<<c0))" 790 return new AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con))); 791 792 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits 793 if( add1_op == Op_AndL ) { 794 Node *add2 = add1->in(1); 795 int add2_op = add2->Opcode(); 796 if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) && 797 add2->in(2) == in(2) ) { 798 // Convert to "(x & (Y<<c0))" 799 Node *y_sh = phase->transform( new LShiftLNode( add1->in(2), in(2) ) ); 800 return new AndLNode( add2->in(1), y_sh ); 801 } 802 } 803 804 // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits 805 // before shifting them away. 806 const jlong bits_mask = jlong(max_julong >> con); 807 if( add1_op == Op_AndL && 808 phase->type(add1->in(2)) == TypeLong::make( bits_mask ) ) 809 return new LShiftLNode( add1->in(1), in(2) ); 810 811 return NULL; 812 } 813 814 //------------------------------Value------------------------------------------ 815 // A LShiftLNode shifts its input2 left by input1 amount. 816 const Type* LShiftLNode::Value(PhaseGVN* phase) const { 817 const Type *t1 = phase->type( in(1) ); 818 const Type *t2 = phase->type( in(2) ); 819 // Either input is TOP ==> the result is TOP 820 if( t1 == Type::TOP ) return Type::TOP; 821 if( t2 == Type::TOP ) return Type::TOP; 822 823 // Left input is ZERO ==> the result is ZERO. 824 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 825 // Shift by zero does nothing 826 if( t2 == TypeInt::ZERO ) return t1; 827 828 // Either input is BOTTOM ==> the result is BOTTOM 829 if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) || 830 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) ) 831 return TypeLong::LONG; 832 833 const TypeLong *r1 = t1->is_long(); // Handy access 834 const TypeInt *r2 = t2->is_int(); // Handy access 835 836 if (!r2->is_con()) 837 return TypeLong::LONG; 838 839 uint shift = r2->get_con(); 840 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 841 // Shift by a multiple of 64 does nothing: 842 if (shift == 0) return t1; 843 844 // If the shift is a constant, shift the bounds of the type, 845 // unless this could lead to an overflow. 846 if (!r1->is_con()) { 847 jlong lo = r1->_lo, hi = r1->_hi; 848 if (((lo << shift) >> shift) == lo && 849 ((hi << shift) >> shift) == hi) { 850 // No overflow. The range shifts up cleanly. 851 return TypeLong::make((jlong)lo << (jint)shift, 852 (jlong)hi << (jint)shift, 853 MAX2(r1->_widen,r2->_widen)); 854 } 855 return TypeLong::LONG; 856 } 857 858 return TypeLong::make( (jlong)r1->get_con() << (jint)shift ); 859 } 860 861 //============================================================================= 862 //------------------------------Identity--------------------------------------- 863 Node* RShiftINode::Identity(PhaseGVN* phase) { 864 const TypeInt *t2 = phase->type(in(2))->isa_int(); 865 if( !t2 ) return this; 866 if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 ) 867 return in(1); 868 869 // Check for useless sign-masking 870 if( in(1)->Opcode() == Op_LShiftI && 871 in(1)->req() == 3 && 872 in(1)->in(2) == in(2) && 873 t2->is_con() ) { 874 uint shift = t2->get_con(); 875 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 876 // Compute masks for which this shifting doesn't change 877 int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000 878 int hi = ~lo; // 00007FFF 879 const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int(); 880 if( !t11 ) return this; 881 // Does actual value fit inside of mask? 882 if( lo <= t11->_lo && t11->_hi <= hi ) 883 return in(1)->in(1); // Then shifting is a nop 884 } 885 886 return this; 887 } 888 889 //------------------------------Ideal------------------------------------------ 890 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 891 // Inputs may be TOP if they are dead. 892 const TypeInt *t1 = phase->type( in(1) )->isa_int(); 893 if( !t1 ) return NULL; // Left input is an integer 894 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 895 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 896 const TypeInt *t3; // type of in(1).in(2) 897 int shift = t2->get_con(); 898 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 899 900 if ( shift == 0 ) return NULL; // let Identity() handle 0 shift count 901 902 // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller. 903 // Such expressions arise normally from shift chains like (byte)(x >> 24). 904 const Node *mask = in(1); 905 if( mask->Opcode() == Op_AndI && 906 (t3 = phase->type(mask->in(2))->isa_int()) && 907 t3->is_con() ) { 908 Node *x = mask->in(1); 909 jint maskbits = t3->get_con(); 910 // Convert to "(x >> shift) & (mask >> shift)" 911 Node *shr_nomask = phase->transform( new RShiftINode(mask->in(1), in(2)) ); 912 return new AndINode(shr_nomask, phase->intcon( maskbits >> shift)); 913 } 914 915 // Check for "(short[i] <<16)>>16" which simply sign-extends 916 const Node *shl = in(1); 917 if( shl->Opcode() != Op_LShiftI ) return NULL; 918 919 if( shift == 16 && 920 (t3 = phase->type(shl->in(2))->isa_int()) && 921 t3->is_con(16) ) { 922 Node *ld = shl->in(1); 923 if( ld->Opcode() == Op_LoadS ) { 924 // Sign extension is just useless here. Return a RShiftI of zero instead 925 // returning 'ld' directly. We cannot return an old Node directly as 926 // that is the job of 'Identity' calls and Identity calls only work on 927 // direct inputs ('ld' is an extra Node removed from 'this'). The 928 // combined optimization requires Identity only return direct inputs. 929 set_req(1, ld); 930 set_req(2, phase->intcon(0)); 931 return this; 932 } 933 else if( can_reshape && 934 ld->Opcode() == Op_LoadUS && 935 ld->outcnt() == 1 && ld->unique_out() == shl) 936 // Replace zero-extension-load with sign-extension-load 937 return new LoadSNode( ld->in(MemNode::Control), 938 ld->in(MemNode::Memory), 939 ld->in(MemNode::Address), 940 ld->adr_type(), TypeInt::SHORT, 941 MemNode::unordered); 942 } 943 944 // Check for "(byte[i] <<24)>>24" which simply sign-extends 945 if( shift == 24 && 946 (t3 = phase->type(shl->in(2))->isa_int()) && 947 t3->is_con(24) ) { 948 Node *ld = shl->in(1); 949 if( ld->Opcode() == Op_LoadB ) { 950 // Sign extension is just useless here 951 set_req(1, ld); 952 set_req(2, phase->intcon(0)); 953 return this; 954 } 955 } 956 957 return NULL; 958 } 959 960 //------------------------------Value------------------------------------------ 961 // A RShiftINode shifts its input2 right by input1 amount. 962 const Type* RShiftINode::Value(PhaseGVN* phase) const { 963 const Type *t1 = phase->type( in(1) ); 964 const Type *t2 = phase->type( in(2) ); 965 // Either input is TOP ==> the result is TOP 966 if( t1 == Type::TOP ) return Type::TOP; 967 if( t2 == Type::TOP ) return Type::TOP; 968 969 // Left input is ZERO ==> the result is ZERO. 970 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 971 // Shift by zero does nothing 972 if( t2 == TypeInt::ZERO ) return t1; 973 974 // Either input is BOTTOM ==> the result is BOTTOM 975 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 976 return TypeInt::INT; 977 978 if (t2 == TypeInt::INT) 979 return TypeInt::INT; 980 981 const TypeInt *r1 = t1->is_int(); // Handy access 982 const TypeInt *r2 = t2->is_int(); // Handy access 983 984 // If the shift is a constant, just shift the bounds of the type. 985 // For example, if the shift is 31, we just propagate sign bits. 986 if (r2->is_con()) { 987 uint shift = r2->get_con(); 988 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 989 // Shift by a multiple of 32 does nothing: 990 if (shift == 0) return t1; 991 // Calculate reasonably aggressive bounds for the result. 992 // This is necessary if we are to correctly type things 993 // like (x<<24>>24) == ((byte)x). 994 jint lo = (jint)r1->_lo >> (jint)shift; 995 jint hi = (jint)r1->_hi >> (jint)shift; 996 assert(lo <= hi, "must have valid bounds"); 997 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 998 #ifdef ASSERT 999 // Make sure we get the sign-capture idiom correct. 1000 if (shift == BitsPerJavaInteger-1) { 1001 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>31 of + is 0"); 1002 if (r1->_hi < 0) assert(ti == TypeInt::MINUS_1, ">>31 of - is -1"); 1003 } 1004 #endif 1005 return ti; 1006 } 1007 1008 if( !r1->is_con() || !r2->is_con() ) 1009 return TypeInt::INT; 1010 1011 // Signed shift right 1012 return TypeInt::make( r1->get_con() >> (r2->get_con()&31) ); 1013 } 1014 1015 //============================================================================= 1016 //------------------------------Identity--------------------------------------- 1017 Node* RShiftLNode::Identity(PhaseGVN* phase) { 1018 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 1019 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 1020 } 1021 1022 //------------------------------Value------------------------------------------ 1023 // A RShiftLNode shifts its input2 right by input1 amount. 1024 const Type* RShiftLNode::Value(PhaseGVN* phase) const { 1025 const Type *t1 = phase->type( in(1) ); 1026 const Type *t2 = phase->type( in(2) ); 1027 // Either input is TOP ==> the result is TOP 1028 if( t1 == Type::TOP ) return Type::TOP; 1029 if( t2 == Type::TOP ) return Type::TOP; 1030 1031 // Left input is ZERO ==> the result is ZERO. 1032 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 1033 // Shift by zero does nothing 1034 if( t2 == TypeInt::ZERO ) return t1; 1035 1036 // Either input is BOTTOM ==> the result is BOTTOM 1037 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1038 return TypeLong::LONG; 1039 1040 if (t2 == TypeInt::INT) 1041 return TypeLong::LONG; 1042 1043 const TypeLong *r1 = t1->is_long(); // Handy access 1044 const TypeInt *r2 = t2->is_int (); // Handy access 1045 1046 // If the shift is a constant, just shift the bounds of the type. 1047 // For example, if the shift is 63, we just propagate sign bits. 1048 if (r2->is_con()) { 1049 uint shift = r2->get_con(); 1050 shift &= (2*BitsPerJavaInteger)-1; // semantics of Java shifts 1051 // Shift by a multiple of 64 does nothing: 1052 if (shift == 0) return t1; 1053 // Calculate reasonably aggressive bounds for the result. 1054 // This is necessary if we are to correctly type things 1055 // like (x<<24>>24) == ((byte)x). 1056 jlong lo = (jlong)r1->_lo >> (jlong)shift; 1057 jlong hi = (jlong)r1->_hi >> (jlong)shift; 1058 assert(lo <= hi, "must have valid bounds"); 1059 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1060 #ifdef ASSERT 1061 // Make sure we get the sign-capture idiom correct. 1062 if (shift == (2*BitsPerJavaInteger)-1) { 1063 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>63 of + is 0"); 1064 if (r1->_hi < 0) assert(tl == TypeLong::MINUS_1, ">>63 of - is -1"); 1065 } 1066 #endif 1067 return tl; 1068 } 1069 1070 return TypeLong::LONG; // Give up 1071 } 1072 1073 //============================================================================= 1074 //------------------------------Identity--------------------------------------- 1075 Node* URShiftINode::Identity(PhaseGVN* phase) { 1076 const TypeInt *ti = phase->type( in(2) )->isa_int(); 1077 if ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) return in(1); 1078 1079 // Check for "((x << LogBytesPerWord) + (wordSize-1)) >> LogBytesPerWord" which is just "x". 1080 // Happens during new-array length computation. 1081 // Safe if 'x' is in the range [0..(max_int>>LogBytesPerWord)] 1082 Node *add = in(1); 1083 if( add->Opcode() == Op_AddI ) { 1084 const TypeInt *t2 = phase->type(add->in(2))->isa_int(); 1085 if( t2 && t2->is_con(wordSize - 1) && 1086 add->in(1)->Opcode() == Op_LShiftI ) { 1087 // Check that shift_counts are LogBytesPerWord 1088 Node *lshift_count = add->in(1)->in(2); 1089 const TypeInt *t_lshift_count = phase->type(lshift_count)->isa_int(); 1090 if( t_lshift_count && t_lshift_count->is_con(LogBytesPerWord) && 1091 t_lshift_count == phase->type(in(2)) ) { 1092 Node *x = add->in(1)->in(1); 1093 const TypeInt *t_x = phase->type(x)->isa_int(); 1094 if( t_x != NULL && 0 <= t_x->_lo && t_x->_hi <= (max_jint>>LogBytesPerWord) ) { 1095 return x; 1096 } 1097 } 1098 } 1099 } 1100 1101 return (phase->type(in(2))->higher_equal(TypeInt::ZERO)) ? in(1) : this; 1102 } 1103 1104 //------------------------------Ideal------------------------------------------ 1105 Node *URShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) { 1106 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 1107 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 1108 const int con = t2->get_con() & 31; // Shift count is always masked 1109 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count 1110 // We'll be wanting the right-shift amount as a mask of that many bits 1111 const int mask = right_n_bits(BitsPerJavaInteger - con); 1112 1113 int in1_op = in(1)->Opcode(); 1114 1115 // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32 1116 if( in1_op == Op_URShiftI ) { 1117 const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int(); 1118 if( t12 && t12->is_con() ) { // Right input is a constant 1119 assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" ); 1120 const int con2 = t12->get_con() & 31; // Shift count is always masked 1121 const int con3 = con+con2; 1122 if( con3 < 32 ) // Only merge shifts if total is < 32 1123 return new URShiftINode( in(1)->in(1), phase->intcon(con3) ); 1124 } 1125 } 1126 1127 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z 1128 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z". 1129 // If Q is "X << z" the rounding is useless. Look for patterns like 1130 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask. 1131 Node *add = in(1); 1132 if( in1_op == Op_AddI ) { 1133 Node *lshl = add->in(1); 1134 if( lshl->Opcode() == Op_LShiftI && 1135 phase->type(lshl->in(2)) == t2 ) { 1136 Node *y_z = phase->transform( new URShiftINode(add->in(2),in(2)) ); 1137 Node *sum = phase->transform( new AddINode( lshl->in(1), y_z ) ); 1138 return new AndINode( sum, phase->intcon(mask) ); 1139 } 1140 } 1141 1142 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z) 1143 // This shortens the mask. Also, if we are extracting a high byte and 1144 // storing it to a buffer, the mask will be removed completely. 1145 Node *andi = in(1); 1146 if( in1_op == Op_AndI ) { 1147 const TypeInt *t3 = phase->type( andi->in(2) )->isa_int(); 1148 if( t3 && t3->is_con() ) { // Right input is a constant 1149 jint mask2 = t3->get_con(); 1150 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help) 1151 Node *newshr = phase->transform( new URShiftINode(andi->in(1), in(2)) ); 1152 return new AndINode(newshr, phase->intcon(mask2)); 1153 // The negative values are easier to materialize than positive ones. 1154 // A typical case from address arithmetic is ((x & ~15) >> 4). 1155 // It's better to change that to ((x >> 4) & ~0) versus 1156 // ((x >> 4) & 0x0FFFFFFF). The difference is greatest in LP64. 1157 } 1158 } 1159 1160 // Check for "(X << z ) >>> z" which simply zero-extends 1161 Node *shl = in(1); 1162 if( in1_op == Op_LShiftI && 1163 phase->type(shl->in(2)) == t2 ) 1164 return new AndINode( shl->in(1), phase->intcon(mask) ); 1165 1166 return NULL; 1167 } 1168 1169 //------------------------------Value------------------------------------------ 1170 // A URShiftINode shifts its input2 right by input1 amount. 1171 const Type* URShiftINode::Value(PhaseGVN* phase) const { 1172 // (This is a near clone of RShiftINode::Value.) 1173 const Type *t1 = phase->type( in(1) ); 1174 const Type *t2 = phase->type( in(2) ); 1175 // Either input is TOP ==> the result is TOP 1176 if( t1 == Type::TOP ) return Type::TOP; 1177 if( t2 == Type::TOP ) return Type::TOP; 1178 1179 // Left input is ZERO ==> the result is ZERO. 1180 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO; 1181 // Shift by zero does nothing 1182 if( t2 == TypeInt::ZERO ) return t1; 1183 1184 // Either input is BOTTOM ==> the result is BOTTOM 1185 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1186 return TypeInt::INT; 1187 1188 if (t2 == TypeInt::INT) 1189 return TypeInt::INT; 1190 1191 const TypeInt *r1 = t1->is_int(); // Handy access 1192 const TypeInt *r2 = t2->is_int(); // Handy access 1193 1194 if (r2->is_con()) { 1195 uint shift = r2->get_con(); 1196 shift &= BitsPerJavaInteger-1; // semantics of Java shifts 1197 // Shift by a multiple of 32 does nothing: 1198 if (shift == 0) return t1; 1199 // Calculate reasonably aggressive bounds for the result. 1200 jint lo = (juint)r1->_lo >> (juint)shift; 1201 jint hi = (juint)r1->_hi >> (juint)shift; 1202 if (r1->_hi >= 0 && r1->_lo < 0) { 1203 // If the type has both negative and positive values, 1204 // there are two separate sub-domains to worry about: 1205 // The positive half and the negative half. 1206 jint neg_lo = lo; 1207 jint neg_hi = (juint)-1 >> (juint)shift; 1208 jint pos_lo = (juint) 0 >> (juint)shift; 1209 jint pos_hi = hi; 1210 lo = MIN2(neg_lo, pos_lo); // == 0 1211 hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift; 1212 } 1213 assert(lo <= hi, "must have valid bounds"); 1214 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1215 #ifdef ASSERT 1216 // Make sure we get the sign-capture idiom correct. 1217 if (shift == BitsPerJavaInteger-1) { 1218 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0"); 1219 if (r1->_hi < 0) assert(ti == TypeInt::ONE, ">>>31 of - is +1"); 1220 } 1221 #endif 1222 return ti; 1223 } 1224 1225 // 1226 // Do not support shifted oops in info for GC 1227 // 1228 // else if( t1->base() == Type::InstPtr ) { 1229 // 1230 // const TypeInstPtr *o = t1->is_instptr(); 1231 // if( t1->singleton() ) 1232 // return TypeInt::make( ((uint32_t)o->const_oop() + o->_offset) >> shift ); 1233 // } 1234 // else if( t1->base() == Type::KlassPtr ) { 1235 // const TypeKlassPtr *o = t1->is_klassptr(); 1236 // if( t1->singleton() ) 1237 // return TypeInt::make( ((uint32_t)o->const_oop() + o->_offset) >> shift ); 1238 // } 1239 1240 return TypeInt::INT; 1241 } 1242 1243 //============================================================================= 1244 //------------------------------Identity--------------------------------------- 1245 Node* URShiftLNode::Identity(PhaseGVN* phase) { 1246 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int 1247 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this; 1248 } 1249 1250 //------------------------------Ideal------------------------------------------ 1251 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1252 const TypeInt *t2 = phase->type( in(2) )->isa_int(); 1253 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant 1254 const int con = t2->get_con() & ( BitsPerLong - 1 ); // Shift count is always masked 1255 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count 1256 // note: mask computation below does not work for 0 shift count 1257 // We'll be wanting the right-shift amount as a mask of that many bits 1258 const jlong mask = jlong(max_julong >> con); 1259 1260 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z 1261 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z". 1262 // If Q is "X << z" the rounding is useless. Look for patterns like 1263 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask. 1264 Node *add = in(1); 1265 if( add->Opcode() == Op_AddL ) { 1266 Node *lshl = add->in(1); 1267 if( lshl->Opcode() == Op_LShiftL && 1268 phase->type(lshl->in(2)) == t2 ) { 1269 Node *y_z = phase->transform( new URShiftLNode(add->in(2),in(2)) ); 1270 Node *sum = phase->transform( new AddLNode( lshl->in(1), y_z ) ); 1271 return new AndLNode( sum, phase->longcon(mask) ); 1272 } 1273 } 1274 1275 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z) 1276 // This shortens the mask. Also, if we are extracting a high byte and 1277 // storing it to a buffer, the mask will be removed completely. 1278 Node *andi = in(1); 1279 if( andi->Opcode() == Op_AndL ) { 1280 const TypeLong *t3 = phase->type( andi->in(2) )->isa_long(); 1281 if( t3 && t3->is_con() ) { // Right input is a constant 1282 jlong mask2 = t3->get_con(); 1283 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help) 1284 Node *newshr = phase->transform( new URShiftLNode(andi->in(1), in(2)) ); 1285 return new AndLNode(newshr, phase->longcon(mask2)); 1286 } 1287 } 1288 1289 // Check for "(X << z ) >>> z" which simply zero-extends 1290 Node *shl = in(1); 1291 if( shl->Opcode() == Op_LShiftL && 1292 phase->type(shl->in(2)) == t2 ) 1293 return new AndLNode( shl->in(1), phase->longcon(mask) ); 1294 1295 return NULL; 1296 } 1297 1298 //------------------------------Value------------------------------------------ 1299 // A URShiftINode shifts its input2 right by input1 amount. 1300 const Type* URShiftLNode::Value(PhaseGVN* phase) const { 1301 // (This is a near clone of RShiftLNode::Value.) 1302 const Type *t1 = phase->type( in(1) ); 1303 const Type *t2 = phase->type( in(2) ); 1304 // Either input is TOP ==> the result is TOP 1305 if( t1 == Type::TOP ) return Type::TOP; 1306 if( t2 == Type::TOP ) return Type::TOP; 1307 1308 // Left input is ZERO ==> the result is ZERO. 1309 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO; 1310 // Shift by zero does nothing 1311 if( t2 == TypeInt::ZERO ) return t1; 1312 1313 // Either input is BOTTOM ==> the result is BOTTOM 1314 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM) 1315 return TypeLong::LONG; 1316 1317 if (t2 == TypeInt::INT) 1318 return TypeLong::LONG; 1319 1320 const TypeLong *r1 = t1->is_long(); // Handy access 1321 const TypeInt *r2 = t2->is_int (); // Handy access 1322 1323 if (r2->is_con()) { 1324 uint shift = r2->get_con(); 1325 shift &= BitsPerJavaLong - 1; // semantics of Java shifts 1326 // Shift by a multiple of 64 does nothing: 1327 if (shift == 0) return t1; 1328 // Calculate reasonably aggressive bounds for the result. 1329 jlong lo = (julong)r1->_lo >> (juint)shift; 1330 jlong hi = (julong)r1->_hi >> (juint)shift; 1331 if (r1->_hi >= 0 && r1->_lo < 0) { 1332 // If the type has both negative and positive values, 1333 // there are two separate sub-domains to worry about: 1334 // The positive half and the negative half. 1335 jlong neg_lo = lo; 1336 jlong neg_hi = (julong)-1 >> (juint)shift; 1337 jlong pos_lo = (julong) 0 >> (juint)shift; 1338 jlong pos_hi = hi; 1339 //lo = MIN2(neg_lo, pos_lo); // == 0 1340 lo = neg_lo < pos_lo ? neg_lo : pos_lo; 1341 //hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift; 1342 hi = neg_hi > pos_hi ? neg_hi : pos_hi; 1343 } 1344 assert(lo <= hi, "must have valid bounds"); 1345 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen)); 1346 #ifdef ASSERT 1347 // Make sure we get the sign-capture idiom correct. 1348 if (shift == BitsPerJavaLong - 1) { 1349 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0"); 1350 if (r1->_hi < 0) assert(tl == TypeLong::ONE, ">>>63 of - is +1"); 1351 } 1352 #endif 1353 return tl; 1354 } 1355 1356 return TypeLong::LONG; // Give up 1357 }