1 /*
2 * Copyright 1997-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // Portions of code courtesy of Clifford Click
26
27 #include "incls/_precompiled.incl"
28 #include "incls/_mulnode.cpp.incl"
29
30
31 //=============================================================================
32 //------------------------------hash-------------------------------------------
33 // Hash function over MulNodes. Needs to be commutative; i.e., I swap
34 // (commute) inputs to MulNodes willy-nilly so the hash function must return
35 // the same value in the presence of edge swapping.
36 uint MulNode::hash() const {
37 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
38 }
39
40 //------------------------------Identity---------------------------------------
41 // Multiplying a one preserves the other argument
42 Node *MulNode::Identity( PhaseTransform *phase ) {
43 register const Type *one = mul_id(); // The multiplicative identity
44 if( phase->type( in(1) )->higher_equal( one ) ) return in(2);
45 if( phase->type( in(2) )->higher_equal( one ) ) return in(1);
46
47 return this;
48 }
49
50 //------------------------------Ideal------------------------------------------
51 // We also canonicalize the Node, moving constants to the right input,
52 // and flatten expressions (so that 1+x+2 becomes x+3).
53 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
54 const Type *t1 = phase->type( in(1) );
55 const Type *t2 = phase->type( in(2) );
56 Node *progress = NULL; // Progress flag
57 // We are OK if right is a constant, or right is a load and
58 // left is a non-constant.
59 if( !(t2->singleton() ||
60 (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) {
61 if( t1->singleton() || // Left input is a constant?
62 // Otherwise, sort inputs (commutativity) to help value numbering.
63 (in(1)->_idx > in(2)->_idx) ) {
64 swap_edges(1, 2);
65 const Type *t = t1;
66 t1 = t2;
67 t2 = t;
68 progress = this; // Made progress
69 }
70 }
71
72 // If the right input is a constant, and the left input is a product of a
73 // constant, flatten the expression tree.
74 uint op = Opcode();
75 if( t2->singleton() && // Right input is a constant?
76 op != Op_MulF && // Float & double cannot reassociate
77 op != Op_MulD ) {
78 if( t2 == Type::TOP ) return NULL;
79 Node *mul1 = in(1);
80 #ifdef ASSERT
81 // Check for dead loop
82 int op1 = mul1->Opcode();
83 if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) ||
84 ( op1 == mul_opcode() || op1 == add_opcode() ) &&
85 ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) ||
86 phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) )
87 assert(false, "dead loop in MulNode::Ideal");
88 #endif
89
90 if( mul1->Opcode() == mul_opcode() ) { // Left input is a multiply?
91 // Mul of a constant?
92 const Type *t12 = phase->type( mul1->in(2) );
93 if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
94 // Compute new constant; check for overflow
95 const Type *tcon01 = mul1->as_Mul()->mul_ring(t2,t12);
96 if( tcon01->singleton() ) {
97 // The Mul of the flattened expression
98 set_req(1, mul1->in(1));
99 set_req(2, phase->makecon( tcon01 ));
100 t2 = tcon01;
101 progress = this; // Made progress
102 }
103 }
104 }
105 // If the right input is a constant, and the left input is an add of a
106 // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0
107 const Node *add1 = in(1);
108 if( add1->Opcode() == add_opcode() ) { // Left input is an add?
109 // Add of a constant?
110 const Type *t12 = phase->type( add1->in(2) );
111 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
112 assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" );
113 // Compute new constant; check for overflow
114 const Type *tcon01 = mul_ring(t2,t12);
115 if( tcon01->singleton() ) {
116
117 // Convert (X+con1)*con0 into X*con0
118 Node *mul = clone(); // mul = ()*con0
119 mul->set_req(1,add1->in(1)); // mul = X*con0
120 mul = phase->transform(mul);
121
122 Node *add2 = add1->clone();
123 add2->set_req(1, mul); // X*con0 + con0*con1
124 add2->set_req(2, phase->makecon(tcon01) );
125 progress = add2;
126 }
127 }
128 } // End of is left input an add
129 } // End of is right input a Mul
130
131 return progress;
132 }
133
134 //------------------------------Value-----------------------------------------
135 const Type *MulNode::Value( PhaseTransform *phase ) const {
136 const Type *t1 = phase->type( in(1) );
137 const Type *t2 = phase->type( in(2) );
138 // Either input is TOP ==> the result is TOP
139 if( t1 == Type::TOP ) return Type::TOP;
140 if( t2 == Type::TOP ) return Type::TOP;
141
142 // Either input is ZERO ==> the result is ZERO.
143 // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0
144 int op = Opcode();
145 if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) {
146 const Type *zero = add_id(); // The multiplicative zero
147 if( t1->higher_equal( zero ) ) return zero;
148 if( t2->higher_equal( zero ) ) return zero;
149 }
150
151 // Either input is BOTTOM ==> the result is the local BOTTOM
152 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
153 return bottom_type();
154
155 #if defined(IA32)
156 // Can't trust native compilers to properly fold strict double
157 // multiplication with round-to-zero on this platform.
158 if (op == Op_MulD && phase->C->method()->is_strict()) {
159 return TypeD::DOUBLE;
160 }
161 #endif
162
163 return mul_ring(t1,t2); // Local flavor of type multiplication
164 }
165
166
167 //=============================================================================
168 //------------------------------Ideal------------------------------------------
169 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
170 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) {
171 // Swap constant to right
172 jint con;
173 if ((con = in(1)->find_int_con(0)) != 0) {
174 swap_edges(1, 2);
175 // Finish rest of method to use info in 'con'
176 } else if ((con = in(2)->find_int_con(0)) == 0) {
177 return MulNode::Ideal(phase, can_reshape);
178 }
179
180 // Now we have a constant Node on the right and the constant in con
181 if( con == 0 ) return NULL; // By zero is handled by Value call
182 if( con == 1 ) return NULL; // By one is handled by Identity call
183
184 // Check for negative constant; if so negate the final result
185 bool sign_flip = false;
186 if( con < 0 ) {
187 con = -con;
188 sign_flip = true;
189 }
190
191 // Get low bit; check for being the only bit
192 Node *res = NULL;
193 jint bit1 = con & -con; // Extract low bit
194 if( bit1 == con ) { // Found a power of 2?
195 res = new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) );
196 } else {
197
198 // Check for constant with 2 bits set
199 jint bit2 = con-bit1;
200 bit2 = bit2 & -bit2; // Extract 2nd bit
201 if( bit2 + bit1 == con ) { // Found all bits in con?
202 Node *n1 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) );
203 Node *n2 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) );
204 res = new (phase->C, 3) AddINode( n2, n1 );
205
206 } else if (is_power_of_2(con+1)) {
207 // Sleezy: power-of-2 -1. Next time be generic.
208 jint temp = (jint) (con + 1);
209 Node *n1 = phase->transform( new (phase->C, 3) LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) );
210 res = new (phase->C, 3) SubINode( n1, in(1) );
211 } else {
212 return MulNode::Ideal(phase, can_reshape);
213 }
214 }
215
216 if( sign_flip ) { // Need to negate result?
217 res = phase->transform(res);// Transform, before making the zero con
218 res = new (phase->C, 3) SubINode(phase->intcon(0),res);
219 }
220
221 return res; // Return final result
222 }
223
224 //------------------------------mul_ring---------------------------------------
225 // Compute the product type of two integer ranges into this node.
226 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const {
227 const TypeInt *r0 = t0->is_int(); // Handy access
228 const TypeInt *r1 = t1->is_int();
229
230 // Fetch endpoints of all ranges
231 int32 lo0 = r0->_lo;
232 double a = (double)lo0;
233 int32 hi0 = r0->_hi;
234 double b = (double)hi0;
235 int32 lo1 = r1->_lo;
236 double c = (double)lo1;
237 int32 hi1 = r1->_hi;
238 double d = (double)hi1;
239
240 // Compute all endpoints & check for overflow
241 int32 A = lo0*lo1;
242 if( (double)A != a*c ) return TypeInt::INT; // Overflow?
243 int32 B = lo0*hi1;
244 if( (double)B != a*d ) return TypeInt::INT; // Overflow?
245 int32 C = hi0*lo1;
246 if( (double)C != b*c ) return TypeInt::INT; // Overflow?
247 int32 D = hi0*hi1;
248 if( (double)D != b*d ) return TypeInt::INT; // Overflow?
249
250 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
251 else { lo0 = B; hi0 = A; }
252 if( C < D ) {
253 if( C < lo0 ) lo0 = C;
254 if( D > hi0 ) hi0 = D;
255 } else {
256 if( D < lo0 ) lo0 = D;
257 if( C > hi0 ) hi0 = C;
258 }
259 return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
260 }
261
262
263 //=============================================================================
264 //------------------------------Ideal------------------------------------------
265 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
266 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
267 // Swap constant to right
268 jlong con;
269 if ((con = in(1)->find_long_con(0)) != 0) {
270 swap_edges(1, 2);
271 // Finish rest of method to use info in 'con'
272 } else if ((con = in(2)->find_long_con(0)) == 0) {
273 return MulNode::Ideal(phase, can_reshape);
274 }
275
276 // Now we have a constant Node on the right and the constant in con
277 if( con == CONST64(0) ) return NULL; // By zero is handled by Value call
278 if( con == CONST64(1) ) return NULL; // By one is handled by Identity call
279
280 // Check for negative constant; if so negate the final result
281 bool sign_flip = false;
282 if( con < 0 ) {
283 con = -con;
284 sign_flip = true;
285 }
286
287 // Get low bit; check for being the only bit
288 Node *res = NULL;
289 jlong bit1 = con & -con; // Extract low bit
290 if( bit1 == con ) { // Found a power of 2?
291 res = new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) );
292 } else {
293
294 // Check for constant with 2 bits set
295 jlong bit2 = con-bit1;
296 bit2 = bit2 & -bit2; // Extract 2nd bit
297 if( bit2 + bit1 == con ) { // Found all bits in con?
298 Node *n1 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) );
299 Node *n2 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) );
300 res = new (phase->C, 3) AddLNode( n2, n1 );
301
302 } else if (is_power_of_2_long(con+1)) {
303 // Sleezy: power-of-2 -1. Next time be generic.
304 jlong temp = (jlong) (con + 1);
305 Node *n1 = phase->transform( new (phase->C, 3) LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) );
306 res = new (phase->C, 3) SubLNode( n1, in(1) );
307 } else {
308 return MulNode::Ideal(phase, can_reshape);
309 }
310 }
311
312 if( sign_flip ) { // Need to negate result?
313 res = phase->transform(res);// Transform, before making the zero con
314 res = new (phase->C, 3) SubLNode(phase->longcon(0),res);
315 }
316
317 return res; // Return final result
318 }
319
320 //------------------------------mul_ring---------------------------------------
321 // Compute the product type of two integer ranges into this node.
322 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const {
323 const TypeLong *r0 = t0->is_long(); // Handy access
324 const TypeLong *r1 = t1->is_long();
325
326 // Fetch endpoints of all ranges
327 jlong lo0 = r0->_lo;
328 double a = (double)lo0;
329 jlong hi0 = r0->_hi;
330 double b = (double)hi0;
331 jlong lo1 = r1->_lo;
332 double c = (double)lo1;
333 jlong hi1 = r1->_hi;
334 double d = (double)hi1;
335
336 // Compute all endpoints & check for overflow
337 jlong A = lo0*lo1;
338 if( (double)A != a*c ) return TypeLong::LONG; // Overflow?
339 jlong B = lo0*hi1;
340 if( (double)B != a*d ) return TypeLong::LONG; // Overflow?
341 jlong C = hi0*lo1;
342 if( (double)C != b*c ) return TypeLong::LONG; // Overflow?
343 jlong D = hi0*hi1;
344 if( (double)D != b*d ) return TypeLong::LONG; // Overflow?
345
346 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
347 else { lo0 = B; hi0 = A; }
348 if( C < D ) {
349 if( C < lo0 ) lo0 = C;
350 if( D > hi0 ) hi0 = D;
351 } else {
352 if( D < lo0 ) lo0 = D;
353 if( C > hi0 ) hi0 = C;
354 }
355 return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
356 }
357
358 //=============================================================================
359 //------------------------------mul_ring---------------------------------------
360 // Compute the product type of two double ranges into this node.
361 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const {
362 if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT;
363 return TypeF::make( t0->getf() * t1->getf() );
364 }
365
366 //=============================================================================
367 //------------------------------mul_ring---------------------------------------
368 // Compute the product type of two double ranges into this node.
369 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const {
370 if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE;
371 // We must be multiplying 2 double constants.
372 return TypeD::make( t0->getd() * t1->getd() );
373 }
374
375 //=============================================================================
376 //------------------------------Value------------------------------------------
377 const Type *MulHiLNode::Value( PhaseTransform *phase ) const {
378 // Either input is TOP ==> the result is TOP
379 const Type *t1 = phase->type( in(1) );
380 const Type *t2 = phase->type( in(2) );
381 if( t1 == Type::TOP ) return Type::TOP;
382 if( t2 == Type::TOP ) return Type::TOP;
383
384 // Either input is BOTTOM ==> the result is the local BOTTOM
385 const Type *bot = bottom_type();
386 if( (t1 == bot) || (t2 == bot) ||
387 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
388 return bot;
389
390 // It is not worth trying to constant fold this stuff!
391 return TypeLong::LONG;
392 }
393
394 //=============================================================================
395 //------------------------------mul_ring---------------------------------------
396 // Supplied function returns the product of the inputs IN THE CURRENT RING.
397 // For the logical operations the ring's MUL is really a logical AND function.
398 // This also type-checks the inputs for sanity. Guaranteed never to
399 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
400 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const {
401 const TypeInt *r0 = t0->is_int(); // Handy access
402 const TypeInt *r1 = t1->is_int();
403 int widen = MAX2(r0->_widen,r1->_widen);
404
405 // If either input is a constant, might be able to trim cases
406 if( !r0->is_con() && !r1->is_con() )
407 return TypeInt::INT; // No constants to be had
408
409 // Both constants? Return bits
410 if( r0->is_con() && r1->is_con() )
411 return TypeInt::make( r0->get_con() & r1->get_con() );
412
413 if( r0->is_con() && r0->get_con() > 0 )
414 return TypeInt::make(0, r0->get_con(), widen);
415
416 if( r1->is_con() && r1->get_con() > 0 )
417 return TypeInt::make(0, r1->get_con(), widen);
418
419 if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) {
420 return TypeInt::BOOL;
421 }
422
423 return TypeInt::INT; // No constants to be had
424 }
425
426 //------------------------------Identity---------------------------------------
427 // Masking off the high bits of an unsigned load is not required
428 Node *AndINode::Identity( PhaseTransform *phase ) {
429
430 // x & x => x
431 if (phase->eqv(in(1), in(2))) return in(1);
432
433 Node* in1 = in(1);
434 uint op = in1->Opcode();
435 const TypeInt* t2 = phase->type(in(2))->isa_int();
436 if (t2 && t2->is_con()) {
437 int con = t2->get_con();
438 // Masking off high bits which are always zero is useless.
439 const TypeInt* t1 = phase->type( in(1) )->isa_int();
440 if (t1 != NULL && t1->_lo >= 0) {
441 jint t1_support = right_n_bits(1 + log2_intptr(t1->_hi));
442 if ((t1_support & con) == t1_support)
443 return in1;
444 }
445 // Masking off the high bits of a unsigned-shift-right is not
446 // needed either.
447 if (op == Op_URShiftI) {
448 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
449 if (t12 && t12->is_con()) { // Shift is by a constant
450 int shift = t12->get_con();
451 shift &= BitsPerJavaInteger - 1; // semantics of Java shifts
452 int mask = max_juint >> shift;
453 if ((mask & con) == mask) // If AND is useless, skip it
454 return in1;
455 }
456 }
457 }
458 return MulNode::Identity(phase);
459 }
460
461 //------------------------------Ideal------------------------------------------
462 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) {
463 // Special case constant AND mask
464 const TypeInt *t2 = phase->type( in(2) )->isa_int();
465 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
466 const int mask = t2->get_con();
467 Node *load = in(1);
468 uint lop = load->Opcode();
469
470 // Masking bits off of a Character? Hi bits are already zero.
471 if( lop == Op_LoadUS &&
472 (mask & 0xFFFF0000) ) // Can we make a smaller mask?
473 return new (phase->C, 3) AndINode(load,phase->intcon(mask&0xFFFF));
474
475 // Masking bits off of a Short? Loading a Character does some masking
476 if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) {
477 Node *ldus = new (phase->C, 3) LoadUSNode(load->in(MemNode::Control),
478 load->in(MemNode::Memory),
479 load->in(MemNode::Address),
480 load->adr_type());
481 ldus = phase->transform(ldus);
482 return new (phase->C, 3) AndINode(ldus, phase->intcon(mask & 0xFFFF));
483 }
484
485 // Masking sign bits off of a Byte? Do an unsigned byte load plus
486 // an and.
487 if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
488 Node* ldub = new (phase->C, 3) LoadUBNode(load->in(MemNode::Control),
489 load->in(MemNode::Memory),
490 load->in(MemNode::Address),
491 load->adr_type());
492 ldub = phase->transform(ldub);
493 return new (phase->C, 3) AndINode(ldub, phase->intcon(mask));
494 }
495
496 // Masking off sign bits? Dont make them!
497 if( lop == Op_RShiftI ) {
498 const TypeInt *t12 = phase->type(load->in(2))->isa_int();
499 if( t12 && t12->is_con() ) { // Shift is by a constant
500 int shift = t12->get_con();
501 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
502 const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift);
503 // If the AND'ing of the 2 masks has no bits, then only original shifted
504 // bits survive. NO sign-extension bits survive the maskings.
505 if( (sign_bits_mask & mask) == 0 ) {
506 // Use zero-fill shift instead
507 Node *zshift = phase->transform(new (phase->C, 3) URShiftINode(load->in(1),load->in(2)));
508 return new (phase->C, 3) AndINode( zshift, in(2) );
509 }
510 }
511 }
512
513 // Check for 'negate/and-1', a pattern emitted when someone asks for
514 // 'mod 2'. Negate leaves the low order bit unchanged (think: complement
515 // plus 1) and the mask is of the low order bit. Skip the negate.
516 if( lop == Op_SubI && mask == 1 && load->in(1) &&
517 phase->type(load->in(1)) == TypeInt::ZERO )
518 return new (phase->C, 3) AndINode( load->in(2), in(2) );
519
520 return MulNode::Ideal(phase, can_reshape);
521 }
522
523 //=============================================================================
524 //------------------------------mul_ring---------------------------------------
525 // Supplied function returns the product of the inputs IN THE CURRENT RING.
526 // For the logical operations the ring's MUL is really a logical AND function.
527 // This also type-checks the inputs for sanity. Guaranteed never to
528 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
529 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const {
530 const TypeLong *r0 = t0->is_long(); // Handy access
531 const TypeLong *r1 = t1->is_long();
532 int widen = MAX2(r0->_widen,r1->_widen);
533
534 // If either input is a constant, might be able to trim cases
535 if( !r0->is_con() && !r1->is_con() )
536 return TypeLong::LONG; // No constants to be had
537
538 // Both constants? Return bits
539 if( r0->is_con() && r1->is_con() )
540 return TypeLong::make( r0->get_con() & r1->get_con() );
541
542 if( r0->is_con() && r0->get_con() > 0 )
543 return TypeLong::make(CONST64(0), r0->get_con(), widen);
544
545 if( r1->is_con() && r1->get_con() > 0 )
546 return TypeLong::make(CONST64(0), r1->get_con(), widen);
547
548 return TypeLong::LONG; // No constants to be had
549 }
550
551 //------------------------------Identity---------------------------------------
552 // Masking off the high bits of an unsigned load is not required
553 Node *AndLNode::Identity( PhaseTransform *phase ) {
554
555 // x & x => x
556 if (phase->eqv(in(1), in(2))) return in(1);
557
558 Node *usr = in(1);
559 const TypeLong *t2 = phase->type( in(2) )->isa_long();
560 if( t2 && t2->is_con() ) {
561 jlong con = t2->get_con();
562 // Masking off high bits which are always zero is useless.
563 const TypeLong* t1 = phase->type( in(1) )->isa_long();
564 if (t1 != NULL && t1->_lo >= 0) {
565 jlong t1_support = ((jlong)1 << (1 + log2_long(t1->_hi))) - 1;
566 if ((t1_support & con) == t1_support)
567 return usr;
568 }
569 uint lop = usr->Opcode();
570 // Masking off the high bits of a unsigned-shift-right is not
571 // needed either.
572 if( lop == Op_URShiftL ) {
573 const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
574 if( t12 && t12->is_con() ) { // Shift is by a constant
575 int shift = t12->get_con();
576 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
577 jlong mask = max_julong >> shift;
578 if( (mask&con) == mask ) // If AND is useless, skip it
579 return usr;
580 }
581 }
582 }
583 return MulNode::Identity(phase);
584 }
585
586 //------------------------------Ideal------------------------------------------
587 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
588 // Special case constant AND mask
589 const TypeLong *t2 = phase->type( in(2) )->isa_long();
590 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
591 const jlong mask = t2->get_con();
592
593 Node* in1 = in(1);
594 uint op = in1->Opcode();
595
596 // Masking sign bits off of an integer? Do an unsigned integer to
597 // long load.
598 // NOTE: This check must be *before* we try to convert the AndLNode
599 // to an AndINode and commute it with ConvI2LNode because
600 // 0xFFFFFFFFL masks the whole integer and we get a sign extension,
601 // which is wrong.
602 if (op == Op_ConvI2L && in1->in(1)->Opcode() == Op_LoadI && mask == CONST64(0x00000000FFFFFFFF)) {
603 Node* load = in1->in(1);
604 return new (phase->C, 3) LoadUI2LNode(load->in(MemNode::Control),
605 load->in(MemNode::Memory),
606 load->in(MemNode::Address),
607 load->adr_type());
608 }
609
610 // Are we masking a long that was converted from an int with a mask
611 // that fits in 32-bits? Commute them and use an AndINode.
612 if (op == Op_ConvI2L && (mask & CONST64(0xFFFFFFFF00000000)) == 0) {
613 // If we are doing an UI2L conversion (i.e. the mask is
614 // 0x00000000FFFFFFFF) we cannot convert the AndL to an AndI
615 // because the AndI would be optimized away later in Identity.
616 if (mask != CONST64(0x00000000FFFFFFFF)) {
617 Node* andi = new (phase->C, 3) AndINode(in1->in(1), phase->intcon(mask));
618 andi = phase->transform(andi);
619 return new (phase->C, 2) ConvI2LNode(andi);
620 }
621 }
622
623 // Masking off sign bits? Dont make them!
624 if (op == Op_RShiftL) {
625 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
626 if( t12 && t12->is_con() ) { // Shift is by a constant
627 int shift = t12->get_con();
628 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
629 const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
630 // If the AND'ing of the 2 masks has no bits, then only original shifted
631 // bits survive. NO sign-extension bits survive the maskings.
632 if( (sign_bits_mask & mask) == 0 ) {
633 // Use zero-fill shift instead
634 Node *zshift = phase->transform(new (phase->C, 3) URShiftLNode(in1->in(1), in1->in(2)));
635 return new (phase->C, 3) AndLNode(zshift, in(2));
636 }
637 }
638 }
639
640 return MulNode::Ideal(phase, can_reshape);
641 }
642
643 //=============================================================================
644 //------------------------------Identity---------------------------------------
645 Node *LShiftINode::Identity( PhaseTransform *phase ) {
646 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
647 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this;
648 }
649
650 //------------------------------Ideal------------------------------------------
651 // If the right input is a constant, and the left input is an add of a
652 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
653 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
654 const Type *t = phase->type( in(2) );
655 if( t == Type::TOP ) return NULL; // Right input is dead
656 const TypeInt *t2 = t->isa_int();
657 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
658 const int con = t2->get_con() & ( BitsPerInt - 1 ); // masked shift count
659
660 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count
661
662 // Left input is an add of a constant?
663 Node *add1 = in(1);
664 int add1_op = add1->Opcode();
665 if( add1_op == Op_AddI ) { // Left input is an add?
666 assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" );
667 const TypeInt *t12 = phase->type(add1->in(2))->isa_int();
668 if( t12 && t12->is_con() ){ // Left input is an add of a con?
669 // Transform is legal, but check for profit. Avoid breaking 'i2s'
670 // and 'i2b' patterns which typically fold into 'StoreC/StoreB'.
671 if( con < 16 ) {
672 // Compute X << con0
673 Node *lsh = phase->transform( new (phase->C, 3) LShiftINode( add1->in(1), in(2) ) );
674 // Compute X<<con0 + (con1<<con0)
675 return new (phase->C, 3) AddINode( lsh, phase->intcon(t12->get_con() << con));
676 }
677 }
678 }
679
680 // Check for "(x>>c0)<<c0" which just masks off low bits
681 if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) &&
682 add1->in(2) == in(2) )
683 // Convert to "(x & -(1<<c0))"
684 return new (phase->C, 3) AndINode(add1->in(1),phase->intcon( -(1<<con)));
685
686 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
687 if( add1_op == Op_AndI ) {
688 Node *add2 = add1->in(1);
689 int add2_op = add2->Opcode();
690 if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) &&
691 add2->in(2) == in(2) ) {
692 // Convert to "(x & (Y<<c0))"
693 Node *y_sh = phase->transform( new (phase->C, 3) LShiftINode( add1->in(2), in(2) ) );
694 return new (phase->C, 3) AndINode( add2->in(1), y_sh );
695 }
696 }
697
698 // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits
699 // before shifting them away.
700 const jint bits_mask = right_n_bits(BitsPerJavaInteger-con);
701 if( add1_op == Op_AndI &&
702 phase->type(add1->in(2)) == TypeInt::make( bits_mask ) )
703 return new (phase->C, 3) LShiftINode( add1->in(1), in(2) );
704
705 return NULL;
706 }
707
708 //------------------------------Value------------------------------------------
709 // A LShiftINode shifts its input2 left by input1 amount.
710 const Type *LShiftINode::Value( PhaseTransform *phase ) const {
711 const Type *t1 = phase->type( in(1) );
712 const Type *t2 = phase->type( in(2) );
713 // Either input is TOP ==> the result is TOP
714 if( t1 == Type::TOP ) return Type::TOP;
715 if( t2 == Type::TOP ) return Type::TOP;
716
717 // Left input is ZERO ==> the result is ZERO.
718 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
719 // Shift by zero does nothing
720 if( t2 == TypeInt::ZERO ) return t1;
721
722 // Either input is BOTTOM ==> the result is BOTTOM
723 if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) ||
724 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
725 return TypeInt::INT;
726
727 const TypeInt *r1 = t1->is_int(); // Handy access
728 const TypeInt *r2 = t2->is_int(); // Handy access
729
730 if (!r2->is_con())
731 return TypeInt::INT;
732
733 uint shift = r2->get_con();
734 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
735 // Shift by a multiple of 32 does nothing:
736 if (shift == 0) return t1;
737
738 // If the shift is a constant, shift the bounds of the type,
739 // unless this could lead to an overflow.
740 if (!r1->is_con()) {
741 jint lo = r1->_lo, hi = r1->_hi;
742 if (((lo << shift) >> shift) == lo &&
743 ((hi << shift) >> shift) == hi) {
744 // No overflow. The range shifts up cleanly.
745 return TypeInt::make((jint)lo << (jint)shift,
746 (jint)hi << (jint)shift,
747 MAX2(r1->_widen,r2->_widen));
748 }
749 return TypeInt::INT;
750 }
751
752 return TypeInt::make( (jint)r1->get_con() << (jint)shift );
753 }
754
755 //=============================================================================
756 //------------------------------Identity---------------------------------------
757 Node *LShiftLNode::Identity( PhaseTransform *phase ) {
758 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
759 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
760 }
761
762 //------------------------------Ideal------------------------------------------
763 // If the right input is a constant, and the left input is an add of a
764 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
765 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
766 const Type *t = phase->type( in(2) );
767 if( t == Type::TOP ) return NULL; // Right input is dead
768 const TypeInt *t2 = t->isa_int();
769 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
770 const int con = t2->get_con() & ( BitsPerLong - 1 ); // masked shift count
771
772 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count
773
774 // Left input is an add of a constant?
775 Node *add1 = in(1);
776 int add1_op = add1->Opcode();
777 if( add1_op == Op_AddL ) { // Left input is an add?
778 // Avoid dead data cycles from dead loops
779 assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" );
780 const TypeLong *t12 = phase->type(add1->in(2))->isa_long();
781 if( t12 && t12->is_con() ){ // Left input is an add of a con?
782 // Compute X << con0
783 Node *lsh = phase->transform( new (phase->C, 3) LShiftLNode( add1->in(1), in(2) ) );
784 // Compute X<<con0 + (con1<<con0)
785 return new (phase->C, 3) AddLNode( lsh, phase->longcon(t12->get_con() << con));
786 }
787 }
788
789 // Check for "(x>>c0)<<c0" which just masks off low bits
790 if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) &&
791 add1->in(2) == in(2) )
792 // Convert to "(x & -(1<<c0))"
793 return new (phase->C, 3) AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con)));
794
795 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
796 if( add1_op == Op_AndL ) {
797 Node *add2 = add1->in(1);
798 int add2_op = add2->Opcode();
799 if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) &&
800 add2->in(2) == in(2) ) {
801 // Convert to "(x & (Y<<c0))"
802 Node *y_sh = phase->transform( new (phase->C, 3) LShiftLNode( add1->in(2), in(2) ) );
803 return new (phase->C, 3) AndLNode( add2->in(1), y_sh );
804 }
805 }
806
807 // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
808 // before shifting them away.
809 const jlong bits_mask = ((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - con)) - CONST64(1);
810 if( add1_op == Op_AndL &&
811 phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
812 return new (phase->C, 3) LShiftLNode( add1->in(1), in(2) );
813
814 return NULL;
815 }
816
817 //------------------------------Value------------------------------------------
818 // A LShiftLNode shifts its input2 left by input1 amount.
819 const Type *LShiftLNode::Value( PhaseTransform *phase ) const {
820 const Type *t1 = phase->type( in(1) );
821 const Type *t2 = phase->type( in(2) );
822 // Either input is TOP ==> the result is TOP
823 if( t1 == Type::TOP ) return Type::TOP;
824 if( t2 == Type::TOP ) return Type::TOP;
825
826 // Left input is ZERO ==> the result is ZERO.
827 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
828 // Shift by zero does nothing
829 if( t2 == TypeInt::ZERO ) return t1;
830
831 // Either input is BOTTOM ==> the result is BOTTOM
832 if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) ||
833 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
834 return TypeLong::LONG;
835
836 const TypeLong *r1 = t1->is_long(); // Handy access
837 const TypeInt *r2 = t2->is_int(); // Handy access
838
839 if (!r2->is_con())
840 return TypeLong::LONG;
841
842 uint shift = r2->get_con();
843 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
844 // Shift by a multiple of 64 does nothing:
845 if (shift == 0) return t1;
846
847 // If the shift is a constant, shift the bounds of the type,
848 // unless this could lead to an overflow.
849 if (!r1->is_con()) {
850 jlong lo = r1->_lo, hi = r1->_hi;
851 if (((lo << shift) >> shift) == lo &&
852 ((hi << shift) >> shift) == hi) {
853 // No overflow. The range shifts up cleanly.
854 return TypeLong::make((jlong)lo << (jint)shift,
855 (jlong)hi << (jint)shift,
856 MAX2(r1->_widen,r2->_widen));
857 }
858 return TypeLong::LONG;
859 }
860
861 return TypeLong::make( (jlong)r1->get_con() << (jint)shift );
862 }
863
864 //=============================================================================
865 //------------------------------Identity---------------------------------------
866 Node *RShiftINode::Identity( PhaseTransform *phase ) {
867 const TypeInt *t2 = phase->type(in(2))->isa_int();
868 if( !t2 ) return this;
869 if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 )
870 return in(1);
871
872 // Check for useless sign-masking
873 if( in(1)->Opcode() == Op_LShiftI &&
874 in(1)->req() == 3 &&
875 in(1)->in(2) == in(2) &&
876 t2->is_con() ) {
877 uint shift = t2->get_con();
878 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
879 // Compute masks for which this shifting doesn't change
880 int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000
881 int hi = ~lo; // 00007FFF
882 const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int();
883 if( !t11 ) return this;
884 // Does actual value fit inside of mask?
885 if( lo <= t11->_lo && t11->_hi <= hi )
886 return in(1)->in(1); // Then shifting is a nop
887 }
888
889 return this;
890 }
891
892 //------------------------------Ideal------------------------------------------
893 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
894 // Inputs may be TOP if they are dead.
895 const TypeInt *t1 = phase->type( in(1) )->isa_int();
896 if( !t1 ) return NULL; // Left input is an integer
897 const TypeInt *t2 = phase->type( in(2) )->isa_int();
898 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
899 const TypeInt *t3; // type of in(1).in(2)
900 int shift = t2->get_con();
901 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
902
903 if ( shift == 0 ) return NULL; // let Identity() handle 0 shift count
904
905 // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller.
906 // Such expressions arise normally from shift chains like (byte)(x >> 24).
907 const Node *mask = in(1);
908 if( mask->Opcode() == Op_AndI &&
909 (t3 = phase->type(mask->in(2))->isa_int()) &&
910 t3->is_con() ) {
911 Node *x = mask->in(1);
912 jint maskbits = t3->get_con();
913 // Convert to "(x >> shift) & (mask >> shift)"
914 Node *shr_nomask = phase->transform( new (phase->C, 3) RShiftINode(mask->in(1), in(2)) );
915 return new (phase->C, 3) AndINode(shr_nomask, phase->intcon( maskbits >> shift));
916 }
917
918 // Check for "(short[i] <<16)>>16" which simply sign-extends
919 const Node *shl = in(1);
920 if( shl->Opcode() != Op_LShiftI ) return NULL;
921
922 if( shift == 16 &&
923 (t3 = phase->type(shl->in(2))->isa_int()) &&
924 t3->is_con(16) ) {
925 Node *ld = shl->in(1);
926 if( ld->Opcode() == Op_LoadS ) {
927 // Sign extension is just useless here. Return a RShiftI of zero instead
928 // returning 'ld' directly. We cannot return an old Node directly as
929 // that is the job of 'Identity' calls and Identity calls only work on
930 // direct inputs ('ld' is an extra Node removed from 'this'). The
931 // combined optimization requires Identity only return direct inputs.
932 set_req(1, ld);
933 set_req(2, phase->intcon(0));
934 return this;
935 }
936 else if( ld->Opcode() == Op_LoadUS )
937 // Replace zero-extension-load with sign-extension-load
938 return new (phase->C, 3) LoadSNode( ld->in(MemNode::Control),
939 ld->in(MemNode::Memory),
940 ld->in(MemNode::Address),
941 ld->adr_type());
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( PhaseTransform *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( PhaseTransform *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( PhaseTransform *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( PhaseTransform *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 (phase->C, 3) 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 (phase->C, 3) URShiftINode(add->in(2),in(2)) );
1137 Node *sum = phase->transform( new (phase->C, 3) AddINode( lshl->in(1), y_z ) );
1138 return new (phase->C, 3) 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 (phase->C, 3) URShiftINode(andi->in(1), in(2)) );
1152 return new (phase->C, 3) 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 (phase->C, 3) 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( PhaseTransform *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)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)o->const_oop() + o->_offset) >> shift );
1238 // }
1239
1240 return TypeInt::INT;
1241 }
1242
1243 //=============================================================================
1244 //------------------------------Identity---------------------------------------
1245 Node *URShiftLNode::Identity( PhaseTransform *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)CONST64(1) << (jlong)(BitsPerJavaLong - con)) -1);
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 (phase->C, 3) URShiftLNode(add->in(2),in(2)) );
1270 Node *sum = phase->transform( new (phase->C, 3) AddLNode( lshl->in(1), y_z ) );
1271 return new (phase->C, 3) 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 (phase->C, 3) URShiftLNode(andi->in(1), in(2)) );
1285 return new (phase->C, 3) 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 (phase->C, 3) 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( PhaseTransform *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 }