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