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 #include "utilities/macros.hpp"
34 #if INCLUDE_ALL_GCS
35 #include "gc_implementation/shenandoah/c2/shenandoahSupport.hpp"
36 #endif
37
38 // Portions of code courtesy of Clifford Click
39
40
41 //=============================================================================
42 //------------------------------hash-------------------------------------------
43 // Hash function over MulNodes. Needs to be commutative; i.e., I swap
44 // (commute) inputs to MulNodes willy-nilly so the hash function must return
45 // the same value in the presence of edge swapping.
46 uint MulNode::hash() const {
47 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
48 }
49
50 //------------------------------Identity---------------------------------------
51 // Multiplying a one preserves the other argument
52 Node *MulNode::Identity( PhaseTransform *phase ) {
53 register const Type *one = mul_id(); // The multiplicative identity
54 if( phase->type( in(1) )->higher_equal( one ) ) return in(2);
55 if( phase->type( in(2) )->higher_equal( one ) ) return in(1);
56
57 return this;
58 }
59
60 //------------------------------Ideal------------------------------------------
61 // We also canonicalize the Node, moving constants to the right input,
62 // and flatten expressions (so that 1+x+2 becomes x+3).
63 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
64 const Type *t1 = phase->type( in(1) );
65 const Type *t2 = phase->type( in(2) );
66 Node *progress = NULL; // Progress flag
67 // We are OK if right is a constant, or right is a load and
68 // left is a non-constant.
69 if( !(t2->singleton() ||
70 (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) {
71 if( t1->singleton() || // Left input is a constant?
72 // Otherwise, sort inputs (commutativity) to help value numbering.
73 (in(1)->_idx > in(2)->_idx) ) {
74 swap_edges(1, 2);
75 const Type *t = t1;
76 t1 = t2;
77 t2 = t;
78 progress = this; // Made progress
79 }
80 }
81
82 // If the right input is a constant, and the left input is a product of a
83 // constant, flatten the expression tree.
84 uint op = Opcode();
85 if( t2->singleton() && // Right input is a constant?
86 op != Op_MulF && // Float & double cannot reassociate
87 op != Op_MulD ) {
88 if( t2 == Type::TOP ) return NULL;
89 Node *mul1 = in(1);
90 #ifdef ASSERT
91 // Check for dead loop
92 int op1 = mul1->Opcode();
93 if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) ||
94 ( op1 == mul_opcode() || op1 == add_opcode() ) &&
95 ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) ||
96 phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) )
97 assert(false, "dead loop in MulNode::Ideal");
98 #endif
99
100 if( mul1->Opcode() == mul_opcode() ) { // Left input is a multiply?
101 // Mul of a constant?
102 const Type *t12 = phase->type( mul1->in(2) );
103 if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
104 // Compute new constant; check for overflow
105 const Type *tcon01 = ((MulNode*)mul1)->mul_ring(t2,t12);
106 if( tcon01->singleton() ) {
107 // The Mul of the flattened expression
108 set_req(1, mul1->in(1));
109 set_req(2, phase->makecon( tcon01 ));
110 t2 = tcon01;
111 progress = this; // Made progress
112 }
113 }
114 }
115 // If the right input is a constant, and the left input is an add of a
116 // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0
117 const Node *add1 = in(1);
118 if( add1->Opcode() == add_opcode() ) { // Left input is an add?
119 // Add of a constant?
120 const Type *t12 = phase->type( add1->in(2) );
121 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
122 assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" );
123 // Compute new constant; check for overflow
124 const Type *tcon01 = mul_ring(t2,t12);
125 if( tcon01->singleton() ) {
126
127 // Convert (X+con1)*con0 into X*con0
128 Node *mul = clone(); // mul = ()*con0
129 mul->set_req(1,add1->in(1)); // mul = X*con0
130 mul = phase->transform(mul);
131
132 Node *add2 = add1->clone();
133 add2->set_req(1, mul); // X*con0 + con0*con1
134 add2->set_req(2, phase->makecon(tcon01) );
135 progress = add2;
136 }
137 }
138 } // End of is left input an add
139 } // End of is right input a Mul
140
141 return progress;
142 }
143
144 //------------------------------Value-----------------------------------------
145 const Type *MulNode::Value( PhaseTransform *phase ) const {
146 const Type *t1 = phase->type( in(1) );
147 const Type *t2 = phase->type( in(2) );
148 // Either input is TOP ==> the result is TOP
149 if( t1 == Type::TOP ) return Type::TOP;
150 if( t2 == Type::TOP ) return Type::TOP;
151
152 // Either input is ZERO ==> the result is ZERO.
153 // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0
154 int op = Opcode();
155 if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) {
156 const Type *zero = add_id(); // The multiplicative zero
157 if( t1->higher_equal( zero ) ) return zero;
158 if( t2->higher_equal( zero ) ) return zero;
159 }
160
161 // Either input is BOTTOM ==> the result is the local BOTTOM
162 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
163 return bottom_type();
164
165 #if defined(IA32)
166 // Can't trust native compilers to properly fold strict double
167 // multiplication with round-to-zero on this platform.
168 if (op == Op_MulD && phase->C->method()->is_strict()) {
169 return TypeD::DOUBLE;
170 }
171 #endif
172
173 return mul_ring(t1,t2); // Local flavor of type multiplication
174 }
175
176 //=============================================================================
177 //------------------------------Ideal------------------------------------------
178 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
179 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) {
180 // Swap constant to right
181 jint con;
182 if ((con = in(1)->find_int_con(0)) != 0) {
183 swap_edges(1, 2);
184 // Finish rest of method to use info in 'con'
185 } else if ((con = in(2)->find_int_con(0)) == 0) {
186 return MulNode::Ideal(phase, can_reshape);
187 }
188
189 // Now we have a constant Node on the right and the constant in con
190 if (con == 0) return NULL; // By zero is handled by Value call
191 if (con == 1) return NULL; // By one is handled by Identity call
192
193 // Check for negative constant; if so negate the final result
194 bool sign_flip = false;
195
196 unsigned int abs_con = uabs(con);
197 if (abs_con != (unsigned int)con) {
198 sign_flip = true;
199 }
200
201 // Get low bit; check for being the only bit
202 Node *res = NULL;
203 unsigned int bit1 = abs_con & (0-abs_con); // Extract low bit
204 if (bit1 == abs_con) { // Found a power of 2?
205 res = new (phase->C) LShiftINode(in(1), phase->intcon(log2_uint(bit1)));
206 } else {
207
208 // Check for constant with 2 bits set
209 unsigned int bit2 = abs_con-bit1;
210 bit2 = bit2 & (0-bit2); // Extract 2nd bit
211 if (bit2 + bit1 == abs_con) { // Found all bits in con?
212 Node *n1 = phase->transform( new (phase->C) LShiftINode(in(1), phase->intcon(log2_uint(bit1))));
213 Node *n2 = phase->transform( new (phase->C) LShiftINode(in(1), phase->intcon(log2_uint(bit2))));
214 res = new (phase->C) AddINode(n2, n1);
215
216 } else if (is_power_of_2(abs_con+1)) {
217 // Sleezy: power-of-2 -1. Next time be generic.
218 unsigned int temp = abs_con + 1;
219 Node *n1 = phase->transform(new (phase->C) LShiftINode(in(1), phase->intcon(log2_uint(temp))));
220 res = new (phase->C) SubINode(n1, in(1));
221 } else {
222 return MulNode::Ideal(phase, can_reshape);
223 }
224 }
225
226 if (sign_flip) { // Need to negate result?
227 res = phase->transform(res);// Transform, before making the zero con
228 res = new (phase->C) SubINode(phase->intcon(0),res);
229 }
230
231 return res; // Return final result
232 }
233
234 //------------------------------mul_ring---------------------------------------
235 // Compute the product type of two integer ranges into this node.
236 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const {
237 const TypeInt *r0 = t0->is_int(); // Handy access
238 const TypeInt *r1 = t1->is_int();
239
240 // Fetch endpoints of all ranges
241 int32 lo0 = r0->_lo;
242 double a = (double)lo0;
243 int32 hi0 = r0->_hi;
244 double b = (double)hi0;
245 int32 lo1 = r1->_lo;
246 double c = (double)lo1;
247 int32 hi1 = r1->_hi;
248 double d = (double)hi1;
249
250 // Compute all endpoints & check for overflow
251 int32 A = java_multiply(lo0, lo1);
252 if( (double)A != a*c ) return TypeInt::INT; // Overflow?
253 int32 B = java_multiply(lo0, hi1);
254 if( (double)B != a*d ) return TypeInt::INT; // Overflow?
255 int32 C = java_multiply(hi0, lo1);
256 if( (double)C != b*c ) return TypeInt::INT; // Overflow?
257 int32 D = java_multiply(hi0, hi1);
258 if( (double)D != b*d ) return TypeInt::INT; // Overflow?
259
260 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
261 else { lo0 = B; hi0 = A; }
262 if( C < D ) {
263 if( C < lo0 ) lo0 = C;
264 if( D > hi0 ) hi0 = D;
265 } else {
266 if( D < lo0 ) lo0 = D;
267 if( C > hi0 ) hi0 = C;
268 }
269 return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
270 }
271
272
273 //=============================================================================
274 //------------------------------Ideal------------------------------------------
275 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
276 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
277 // Swap constant to right
278 jlong con;
279 if ((con = in(1)->find_long_con(0)) != 0) {
280 swap_edges(1, 2);
281 // Finish rest of method to use info in 'con'
282 } else if ((con = in(2)->find_long_con(0)) == 0) {
283 return MulNode::Ideal(phase, can_reshape);
284 }
285
286 // Now we have a constant Node on the right and the constant in con
287 if (con == CONST64(0)) return NULL; // By zero is handled by Value call
288 if (con == CONST64(1)) return NULL; // By one is handled by Identity call
289
290 // Check for negative constant; if so negate the final result
291 bool sign_flip = false;
292 julong abs_con = uabs(con);
293 if (abs_con != (julong)con) {
294 sign_flip = true;
295 }
296
297 // Get low bit; check for being the only bit
298 Node *res = NULL;
299 julong bit1 = abs_con & (0-abs_con); // Extract low bit
300 if (bit1 == abs_con) { // Found a power of 2?
301 res = new (phase->C) LShiftLNode(in(1), phase->intcon(log2_long(bit1)));
302 } else {
303
304 // Check for constant with 2 bits set
305 julong bit2 = abs_con-bit1;
306 bit2 = bit2 & (0-bit2); // Extract 2nd bit
307 if (bit2 + bit1 == abs_con) { // Found all bits in con?
308 Node *n1 = phase->transform(new (phase->C) LShiftLNode(in(1), phase->intcon(log2_long(bit1))));
309 Node *n2 = phase->transform(new (phase->C) LShiftLNode(in(1), phase->intcon(log2_long(bit2))));
310 res = new (phase->C) AddLNode(n2, n1);
311
312 } else if (is_power_of_2_long(abs_con+1)) {
313 // Sleezy: power-of-2 -1. Next time be generic.
314 julong temp = abs_con + 1;
315 Node *n1 = phase->transform( new (phase->C) LShiftLNode(in(1), phase->intcon(log2_long(temp))));
316 res = new (phase->C) SubLNode(n1, in(1));
317 } else {
318 return MulNode::Ideal(phase, can_reshape);
319 }
320 }
321
322 if (sign_flip) { // Need to negate result?
323 res = phase->transform(res);// Transform, before making the zero con
324 res = new (phase->C) SubLNode(phase->longcon(0),res);
325 }
326
327 return res; // Return final result
328 }
329
330 //------------------------------mul_ring---------------------------------------
331 // Compute the product type of two integer ranges into this node.
332 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const {
333 const TypeLong *r0 = t0->is_long(); // Handy access
334 const TypeLong *r1 = t1->is_long();
335
336 // Fetch endpoints of all ranges
337 jlong lo0 = r0->_lo;
338 double a = (double)lo0;
339 jlong hi0 = r0->_hi;
340 double b = (double)hi0;
341 jlong lo1 = r1->_lo;
342 double c = (double)lo1;
343 jlong hi1 = r1->_hi;
344 double d = (double)hi1;
345
346 // Compute all endpoints & check for overflow
347 jlong A = java_multiply(lo0, lo1);
348 if( (double)A != a*c ) return TypeLong::LONG; // Overflow?
349 jlong B = java_multiply(lo0, hi1);
350 if( (double)B != a*d ) return TypeLong::LONG; // Overflow?
351 jlong C = java_multiply(hi0, lo1);
352 if( (double)C != b*c ) return TypeLong::LONG; // Overflow?
353 jlong D = java_multiply(hi0, hi1);
354 if( (double)D != b*d ) return TypeLong::LONG; // Overflow?
355
356 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
357 else { lo0 = B; hi0 = A; }
358 if( C < D ) {
359 if( C < lo0 ) lo0 = C;
360 if( D > hi0 ) hi0 = D;
361 } else {
362 if( D < lo0 ) lo0 = D;
363 if( C > hi0 ) hi0 = C;
364 }
365 return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
366 }
367
368 //=============================================================================
369 //------------------------------mul_ring---------------------------------------
370 // Compute the product type of two double ranges into this node.
371 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const {
372 if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT;
373 return TypeF::make( t0->getf() * t1->getf() );
374 }
375
376 //=============================================================================
377 //------------------------------mul_ring---------------------------------------
378 // Compute the product type of two double ranges into this node.
379 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const {
380 if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE;
381 // We must be multiplying 2 double constants.
382 return TypeD::make( t0->getd() * t1->getd() );
383 }
384
385 //=============================================================================
386 //------------------------------Value------------------------------------------
387 const Type *MulHiLNode::Value( PhaseTransform *phase ) const {
388 // Either input is TOP ==> the result is TOP
389 const Type *t1 = phase->type( in(1) );
390 const Type *t2 = phase->type( in(2) );
391 if( t1 == Type::TOP ) return Type::TOP;
392 if( t2 == Type::TOP ) return Type::TOP;
393
394 // Either input is BOTTOM ==> the result is the local BOTTOM
395 const Type *bot = bottom_type();
396 if( (t1 == bot) || (t2 == bot) ||
397 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
398 return bot;
399
400 // It is not worth trying to constant fold this stuff!
401 return TypeLong::LONG;
402 }
403
404 //=============================================================================
405 //------------------------------mul_ring---------------------------------------
406 // Supplied function returns the product of the inputs IN THE CURRENT RING.
407 // For the logical operations the ring's MUL is really a logical AND function.
408 // This also type-checks the inputs for sanity. Guaranteed never to
409 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
410 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const {
411 const TypeInt *r0 = t0->is_int(); // Handy access
412 const TypeInt *r1 = t1->is_int();
413 int widen = MAX2(r0->_widen,r1->_widen);
414
415 // If either input is a constant, might be able to trim cases
416 if( !r0->is_con() && !r1->is_con() )
417 return TypeInt::INT; // No constants to be had
418
419 // Both constants? Return bits
420 if( r0->is_con() && r1->is_con() )
421 return TypeInt::make( r0->get_con() & r1->get_con() );
422
423 if( r0->is_con() && r0->get_con() > 0 )
424 return TypeInt::make(0, r0->get_con(), widen);
425
426 if( r1->is_con() && r1->get_con() > 0 )
427 return TypeInt::make(0, r1->get_con(), widen);
428
429 if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) {
430 return TypeInt::BOOL;
431 }
432
433 return TypeInt::INT; // No constants to be had
434 }
435
436 //------------------------------Identity---------------------------------------
437 // Masking off the high bits of an unsigned load is not required
438 Node *AndINode::Identity( PhaseTransform *phase ) {
439
440 // x & x => x
441 if (phase->eqv(in(1), in(2))) return in(1);
442
443 Node* in1 = in(1);
444 uint op = in1->Opcode();
445 const TypeInt* t2 = phase->type(in(2))->isa_int();
446 if (t2 && t2->is_con()) {
447 int con = t2->get_con();
448 // Masking off high bits which are always zero is useless.
449 const TypeInt* t1 = phase->type( in(1) )->isa_int();
450 if (t1 != NULL && t1->_lo >= 0) {
451 jint t1_support = right_n_bits(1 + log2_jint(t1->_hi));
452 if ((t1_support & con) == t1_support)
453 return in1;
454 }
455 // Masking off the high bits of a unsigned-shift-right is not
456 // needed either.
457 if (op == Op_URShiftI) {
458 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
459 if (t12 && t12->is_con()) { // Shift is by a constant
460 int shift = t12->get_con();
461 shift &= BitsPerJavaInteger - 1; // semantics of Java shifts
462 int mask = max_juint >> shift;
463 if ((mask & con) == mask) // If AND is useless, skip it
464 return in1;
465 }
466 }
467 }
468 return MulNode::Identity(phase);
469 }
470
471 //------------------------------Ideal------------------------------------------
472 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) {
473 // Special case constant AND mask
474 const TypeInt *t2 = phase->type( in(2) )->isa_int();
475 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
476 const int mask = t2->get_con();
477 Node *load = in(1);
478 uint lop = load->Opcode();
479
480 #if INCLUDE_ALL_GCS
481 if (UseShenandoahGC && ShenandoahBarrierC2Support::is_gc_state_load(load)) {
482 // Do not touch the load+mask, we would match the whole sequence exactly.
483 // Converting the load to LoadUB/LoadUS would mismatch and waste a register
484 // on the barrier fastpath.
485 return NULL;
486 }
487 #endif
488
489 // Masking bits off of a Character? Hi bits are already zero.
490 if( lop == Op_LoadUS &&
491 (mask & 0xFFFF0000) ) // Can we make a smaller mask?
492 return new (phase->C) AndINode(load,phase->intcon(mask&0xFFFF));
493
494 // Masking bits off of a Short? Loading a Character does some masking
495 if (can_reshape &&
496 load->outcnt() == 1 && load->unique_out() == this) {
497 if (lop == Op_LoadS && (mask & 0xFFFF0000) == 0 ) {
498 Node *ldus = new (phase->C) LoadUSNode(load->in(MemNode::Control),
499 load->in(MemNode::Memory),
500 load->in(MemNode::Address),
501 load->adr_type(),
502 TypeInt::CHAR, MemNode::unordered);
503 ldus = phase->transform(ldus);
504 return new (phase->C) AndINode(ldus, phase->intcon(mask & 0xFFFF));
505 }
506
507 // Masking sign bits off of a Byte? Do an unsigned byte load plus
508 // an and.
509 if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
510 Node* ldub = new (phase->C) LoadUBNode(load->in(MemNode::Control),
511 load->in(MemNode::Memory),
512 load->in(MemNode::Address),
513 load->adr_type(),
514 TypeInt::UBYTE, MemNode::unordered);
515 ldub = phase->transform(ldub);
516 return new (phase->C) AndINode(ldub, phase->intcon(mask));
517 }
518 }
519
520 // Masking off sign bits? Dont make them!
521 if( lop == Op_RShiftI ) {
522 const TypeInt *t12 = phase->type(load->in(2))->isa_int();
523 if( t12 && t12->is_con() ) { // Shift is by a constant
524 int shift = t12->get_con();
525 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
526 const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift);
527 // If the AND'ing of the 2 masks has no bits, then only original shifted
528 // bits survive. NO sign-extension bits survive the maskings.
529 if( (sign_bits_mask & mask) == 0 ) {
530 // Use zero-fill shift instead
531 Node *zshift = phase->transform(new (phase->C) URShiftINode(load->in(1),load->in(2)));
532 return new (phase->C) AndINode( zshift, in(2) );
533 }
534 }
535 }
536
537 // Check for 'negate/and-1', a pattern emitted when someone asks for
538 // 'mod 2'. Negate leaves the low order bit unchanged (think: complement
539 // plus 1) and the mask is of the low order bit. Skip the negate.
540 if( lop == Op_SubI && mask == 1 && load->in(1) &&
541 phase->type(load->in(1)) == TypeInt::ZERO )
542 return new (phase->C) AndINode( load->in(2), in(2) );
543
544 return MulNode::Ideal(phase, can_reshape);
545 }
546
547 //=============================================================================
548 //------------------------------mul_ring---------------------------------------
549 // Supplied function returns the product of the inputs IN THE CURRENT RING.
550 // For the logical operations the ring's MUL is really a logical AND function.
551 // This also type-checks the inputs for sanity. Guaranteed never to
552 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
553 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const {
554 const TypeLong *r0 = t0->is_long(); // Handy access
555 const TypeLong *r1 = t1->is_long();
556 int widen = MAX2(r0->_widen,r1->_widen);
557
558 // If either input is a constant, might be able to trim cases
559 if( !r0->is_con() && !r1->is_con() )
560 return TypeLong::LONG; // No constants to be had
561
562 // Both constants? Return bits
563 if( r0->is_con() && r1->is_con() )
564 return TypeLong::make( r0->get_con() & r1->get_con() );
565
566 if( r0->is_con() && r0->get_con() > 0 )
567 return TypeLong::make(CONST64(0), r0->get_con(), widen);
568
569 if( r1->is_con() && r1->get_con() > 0 )
570 return TypeLong::make(CONST64(0), r1->get_con(), widen);
571
572 return TypeLong::LONG; // No constants to be had
573 }
574
575 //------------------------------Identity---------------------------------------
576 // Masking off the high bits of an unsigned load is not required
577 Node *AndLNode::Identity( PhaseTransform *phase ) {
578
579 // x & x => x
580 if (phase->eqv(in(1), in(2))) return in(1);
581
582 Node *usr = in(1);
583 const TypeLong *t2 = phase->type( in(2) )->isa_long();
584 if( t2 && t2->is_con() ) {
585 jlong con = t2->get_con();
586 // Masking off high bits which are always zero is useless.
587 const TypeLong* t1 = phase->type( in(1) )->isa_long();
588 if (t1 != NULL && t1->_lo >= 0) {
589 int bit_count = log2_long(t1->_hi) + 1;
590 jlong t1_support = jlong(max_julong >> (BitsPerJavaLong - bit_count));
591 if ((t1_support & con) == t1_support)
592 return usr;
593 }
594 uint lop = usr->Opcode();
595 // Masking off the high bits of a unsigned-shift-right is not
596 // needed either.
597 if( lop == Op_URShiftL ) {
598 const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
599 if( t12 && t12->is_con() ) { // Shift is by a constant
600 int shift = t12->get_con();
601 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
602 jlong mask = max_julong >> shift;
603 if( (mask&con) == mask ) // If AND is useless, skip it
604 return usr;
605 }
606 }
607 }
608 return MulNode::Identity(phase);
609 }
610
611 //------------------------------Ideal------------------------------------------
612 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
613 // Special case constant AND mask
614 const TypeLong *t2 = phase->type( in(2) )->isa_long();
615 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
616 const jlong mask = t2->get_con();
617
618 Node* in1 = in(1);
619 uint op = in1->Opcode();
620
621 // Are we masking a long that was converted from an int with a mask
622 // that fits in 32-bits? Commute them and use an AndINode. Don't
623 // convert masks which would cause a sign extension of the integer
624 // value. This check includes UI2L masks (0x00000000FFFFFFFF) which
625 // would be optimized away later in Identity.
626 if (op == Op_ConvI2L && (mask & CONST64(0xFFFFFFFF80000000)) == 0) {
627 Node* andi = new (phase->C) AndINode(in1->in(1), phase->intcon(mask));
628 andi = phase->transform(andi);
629 return new (phase->C) ConvI2LNode(andi);
630 }
631
632 // Masking off sign bits? Dont make them!
633 if (op == Op_RShiftL) {
634 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
635 if( t12 && t12->is_con() ) { // Shift is by a constant
636 int shift = t12->get_con();
637 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
638 const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
639 // If the AND'ing of the 2 masks has no bits, then only original shifted
640 // bits survive. NO sign-extension bits survive the maskings.
641 if( (sign_bits_mask & mask) == 0 ) {
642 // Use zero-fill shift instead
643 Node *zshift = phase->transform(new (phase->C) URShiftLNode(in1->in(1), in1->in(2)));
644 return new (phase->C) AndLNode(zshift, in(2));
645 }
646 }
647 }
648
649 return MulNode::Ideal(phase, can_reshape);
650 }
651
652 //=============================================================================
653 //------------------------------Identity---------------------------------------
654 Node *LShiftINode::Identity( PhaseTransform *phase ) {
655 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
656 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) ? in(1) : this;
657 }
658
659 //------------------------------Ideal------------------------------------------
660 // If the right input is a constant, and the left input is an add of a
661 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
662 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
663 const Type *t = phase->type( in(2) );
664 if( t == Type::TOP ) return NULL; // Right input is dead
665 const TypeInt *t2 = t->isa_int();
666 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
667 const int con = t2->get_con() & ( BitsPerInt - 1 ); // masked shift count
668
669 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count
670
671 // Left input is an add of a constant?
672 Node *add1 = in(1);
673 int add1_op = add1->Opcode();
674 if( add1_op == Op_AddI ) { // Left input is an add?
675 assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" );
676 const TypeInt *t12 = phase->type(add1->in(2))->isa_int();
677 if( t12 && t12->is_con() ){ // Left input is an add of a con?
678 // Transform is legal, but check for profit. Avoid breaking 'i2s'
679 // and 'i2b' patterns which typically fold into 'StoreC/StoreB'.
680 if( con < 16 ) {
681 // Compute X << con0
682 Node *lsh = phase->transform( new (phase->C) LShiftINode( add1->in(1), in(2) ) );
683 // Compute X<<con0 + (con1<<con0)
684 return new (phase->C) AddINode( lsh, phase->intcon(t12->get_con() << con));
685 }
686 }
687 }
688
689 // Check for "(x>>c0)<<c0" which just masks off low bits
690 if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) &&
691 add1->in(2) == in(2) )
692 // Convert to "(x & -(1<<c0))"
693 return new (phase->C) AndINode(add1->in(1),phase->intcon( -(1<<con)));
694
695 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
696 if( add1_op == Op_AndI ) {
697 Node *add2 = add1->in(1);
698 int add2_op = add2->Opcode();
699 if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) &&
700 add2->in(2) == in(2) ) {
701 // Convert to "(x & (Y<<c0))"
702 Node *y_sh = phase->transform( new (phase->C) LShiftINode( add1->in(2), in(2) ) );
703 return new (phase->C) AndINode( add2->in(1), y_sh );
704 }
705 }
706
707 // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits
708 // before shifting them away.
709 const jint bits_mask = right_n_bits(BitsPerJavaInteger-con);
710 if( add1_op == Op_AndI &&
711 phase->type(add1->in(2)) == TypeInt::make( bits_mask ) )
712 return new (phase->C) LShiftINode( add1->in(1), in(2) );
713
714 return NULL;
715 }
716
717 //------------------------------Value------------------------------------------
718 // A LShiftINode shifts its input2 left by input1 amount.
719 const Type *LShiftINode::Value( PhaseTransform *phase ) const {
720 const Type *t1 = phase->type( in(1) );
721 const Type *t2 = phase->type( in(2) );
722 // Either input is TOP ==> the result is TOP
723 if( t1 == Type::TOP ) return Type::TOP;
724 if( t2 == Type::TOP ) return Type::TOP;
725
726 // Left input is ZERO ==> the result is ZERO.
727 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
728 // Shift by zero does nothing
729 if( t2 == TypeInt::ZERO ) return t1;
730
731 // Either input is BOTTOM ==> the result is BOTTOM
732 if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) ||
733 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
734 return TypeInt::INT;
735
736 const TypeInt *r1 = t1->is_int(); // Handy access
737 const TypeInt *r2 = t2->is_int(); // Handy access
738
739 if (!r2->is_con())
740 return TypeInt::INT;
741
742 uint shift = r2->get_con();
743 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
744 // Shift by a multiple of 32 does nothing:
745 if (shift == 0) return t1;
746
747 // If the shift is a constant, shift the bounds of the type,
748 // unless this could lead to an overflow.
749 if (!r1->is_con()) {
750 jint lo = r1->_lo, hi = r1->_hi;
751 if (((lo << shift) >> shift) == lo &&
752 ((hi << shift) >> shift) == hi) {
753 // No overflow. The range shifts up cleanly.
754 return TypeInt::make((jint)lo << (jint)shift,
755 (jint)hi << (jint)shift,
756 MAX2(r1->_widen,r2->_widen));
757 }
758 return TypeInt::INT;
759 }
760
761 return TypeInt::make( (jint)r1->get_con() << (jint)shift );
762 }
763
764 //=============================================================================
765 //------------------------------Identity---------------------------------------
766 Node *LShiftLNode::Identity( PhaseTransform *phase ) {
767 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
768 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
769 }
770
771 //------------------------------Ideal------------------------------------------
772 // If the right input is a constant, and the left input is an add of a
773 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
774 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
775 const Type *t = phase->type( in(2) );
776 if( t == Type::TOP ) return NULL; // Right input is dead
777 const TypeInt *t2 = t->isa_int();
778 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
779 const int con = t2->get_con() & ( BitsPerLong - 1 ); // masked shift count
780
781 if ( con == 0 ) return NULL; // let Identity() handle 0 shift count
782
783 // Left input is an add of a constant?
784 Node *add1 = in(1);
785 int add1_op = add1->Opcode();
786 if( add1_op == Op_AddL ) { // Left input is an add?
787 // Avoid dead data cycles from dead loops
788 assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" );
789 const TypeLong *t12 = phase->type(add1->in(2))->isa_long();
790 if( t12 && t12->is_con() ){ // Left input is an add of a con?
791 // Compute X << con0
792 Node *lsh = phase->transform( new (phase->C) LShiftLNode( add1->in(1), in(2) ) );
793 // Compute X<<con0 + (con1<<con0)
794 return new (phase->C) AddLNode( lsh, phase->longcon(t12->get_con() << con));
795 }
796 }
797
798 // Check for "(x>>c0)<<c0" which just masks off low bits
799 if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) &&
800 add1->in(2) == in(2) )
801 // Convert to "(x & -(1<<c0))"
802 return new (phase->C) AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con)));
803
804 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
805 if( add1_op == Op_AndL ) {
806 Node *add2 = add1->in(1);
807 int add2_op = add2->Opcode();
808 if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) &&
809 add2->in(2) == in(2) ) {
810 // Convert to "(x & (Y<<c0))"
811 Node *y_sh = phase->transform( new (phase->C) LShiftLNode( add1->in(2), in(2) ) );
812 return new (phase->C) AndLNode( add2->in(1), y_sh );
813 }
814 }
815
816 // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
817 // before shifting them away.
818 const jlong bits_mask = jlong(max_julong >> con);
819 if( add1_op == Op_AndL &&
820 phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
821 return new (phase->C) LShiftLNode( add1->in(1), in(2) );
822
823 return NULL;
824 }
825
826 //------------------------------Value------------------------------------------
827 // A LShiftLNode shifts its input2 left by input1 amount.
828 const Type *LShiftLNode::Value( PhaseTransform *phase ) const {
829 const Type *t1 = phase->type( in(1) );
830 const Type *t2 = phase->type( in(2) );
831 // Either input is TOP ==> the result is TOP
832 if( t1 == Type::TOP ) return Type::TOP;
833 if( t2 == Type::TOP ) return Type::TOP;
834
835 // Left input is ZERO ==> the result is ZERO.
836 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
837 // Shift by zero does nothing
838 if( t2 == TypeInt::ZERO ) return t1;
839
840 // Either input is BOTTOM ==> the result is BOTTOM
841 if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) ||
842 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
843 return TypeLong::LONG;
844
845 const TypeLong *r1 = t1->is_long(); // Handy access
846 const TypeInt *r2 = t2->is_int(); // Handy access
847
848 if (!r2->is_con())
849 return TypeLong::LONG;
850
851 uint shift = r2->get_con();
852 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
853 // Shift by a multiple of 64 does nothing:
854 if (shift == 0) return t1;
855
856 // If the shift is a constant, shift the bounds of the type,
857 // unless this could lead to an overflow.
858 if (!r1->is_con()) {
859 jlong lo = r1->_lo, hi = r1->_hi;
860 if (((lo << shift) >> shift) == lo &&
861 ((hi << shift) >> shift) == hi) {
862 // No overflow. The range shifts up cleanly.
863 return TypeLong::make((jlong)lo << (jint)shift,
864 (jlong)hi << (jint)shift,
865 MAX2(r1->_widen,r2->_widen));
866 }
867 return TypeLong::LONG;
868 }
869
870 return TypeLong::make( (jlong)r1->get_con() << (jint)shift );
871 }
872
873 //=============================================================================
874 //------------------------------Identity---------------------------------------
875 Node *RShiftINode::Identity( PhaseTransform *phase ) {
876 const TypeInt *t2 = phase->type(in(2))->isa_int();
877 if( !t2 ) return this;
878 if ( t2->is_con() && ( t2->get_con() & ( BitsPerInt - 1 ) ) == 0 )
879 return in(1);
880
881 // Check for useless sign-masking
882 if( in(1)->Opcode() == Op_LShiftI &&
883 in(1)->req() == 3 &&
884 in(1)->in(2) == in(2) &&
885 t2->is_con() ) {
886 uint shift = t2->get_con();
887 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
888 // Compute masks for which this shifting doesn't change
889 int lo = (-1 << (BitsPerJavaInteger - shift-1)); // FFFF8000
890 int hi = ~lo; // 00007FFF
891 const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int();
892 if( !t11 ) return this;
893 // Does actual value fit inside of mask?
894 if( lo <= t11->_lo && t11->_hi <= hi )
895 return in(1)->in(1); // Then shifting is a nop
896 }
897
898 return this;
899 }
900
901 //------------------------------Ideal------------------------------------------
902 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
903 // Inputs may be TOP if they are dead.
904 const TypeInt *t1 = phase->type( in(1) )->isa_int();
905 if( !t1 ) return NULL; // Left input is an integer
906 const TypeInt *t2 = phase->type( in(2) )->isa_int();
907 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
908 const TypeInt *t3; // type of in(1).in(2)
909 int shift = t2->get_con();
910 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
911
912 if ( shift == 0 ) return NULL; // let Identity() handle 0 shift count
913
914 // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller.
915 // Such expressions arise normally from shift chains like (byte)(x >> 24).
916 const Node *mask = in(1);
917 if( mask->Opcode() == Op_AndI &&
918 (t3 = phase->type(mask->in(2))->isa_int()) &&
919 t3->is_con() ) {
920 Node *x = mask->in(1);
921 jint maskbits = t3->get_con();
922 // Convert to "(x >> shift) & (mask >> shift)"
923 Node *shr_nomask = phase->transform( new (phase->C) RShiftINode(mask->in(1), in(2)) );
924 return new (phase->C) AndINode(shr_nomask, phase->intcon( maskbits >> shift));
925 }
926
927 // Check for "(short[i] <<16)>>16" which simply sign-extends
928 const Node *shl = in(1);
929 if( shl->Opcode() != Op_LShiftI ) return NULL;
930
931 if( shift == 16 &&
932 (t3 = phase->type(shl->in(2))->isa_int()) &&
933 t3->is_con(16) ) {
934 Node *ld = shl->in(1);
935 if( ld->Opcode() == Op_LoadS ) {
936 // Sign extension is just useless here. Return a RShiftI of zero instead
937 // returning 'ld' directly. We cannot return an old Node directly as
938 // that is the job of 'Identity' calls and Identity calls only work on
939 // direct inputs ('ld' is an extra Node removed from 'this'). The
940 // combined optimization requires Identity only return direct inputs.
941 set_req(1, ld);
942 set_req(2, phase->intcon(0));
943 return this;
944 }
945 else if( can_reshape &&
946 ld->Opcode() == Op_LoadUS &&
947 ld->outcnt() == 1 && ld->unique_out() == shl)
948 // Replace zero-extension-load with sign-extension-load
949 return new (phase->C) LoadSNode( ld->in(MemNode::Control),
950 ld->in(MemNode::Memory),
951 ld->in(MemNode::Address),
952 ld->adr_type(), TypeInt::SHORT,
953 MemNode::unordered);
954 }
955
956 // Check for "(byte[i] <<24)>>24" which simply sign-extends
957 if( shift == 24 &&
958 (t3 = phase->type(shl->in(2))->isa_int()) &&
959 t3->is_con(24) ) {
960 Node *ld = shl->in(1);
961 if( ld->Opcode() == Op_LoadB ) {
962 // Sign extension is just useless here
963 set_req(1, ld);
964 set_req(2, phase->intcon(0));
965 return this;
966 }
967 }
968
969 return NULL;
970 }
971
972 //------------------------------Value------------------------------------------
973 // A RShiftINode shifts its input2 right by input1 amount.
974 const Type *RShiftINode::Value( PhaseTransform *phase ) const {
975 const Type *t1 = phase->type( in(1) );
976 const Type *t2 = phase->type( in(2) );
977 // Either input is TOP ==> the result is TOP
978 if( t1 == Type::TOP ) return Type::TOP;
979 if( t2 == Type::TOP ) return Type::TOP;
980
981 // Left input is ZERO ==> the result is ZERO.
982 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
983 // Shift by zero does nothing
984 if( t2 == TypeInt::ZERO ) return t1;
985
986 // Either input is BOTTOM ==> the result is BOTTOM
987 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
988 return TypeInt::INT;
989
990 if (t2 == TypeInt::INT)
991 return TypeInt::INT;
992
993 const TypeInt *r1 = t1->is_int(); // Handy access
994 const TypeInt *r2 = t2->is_int(); // Handy access
995
996 // If the shift is a constant, just shift the bounds of the type.
997 // For example, if the shift is 31, we just propagate sign bits.
998 if (r2->is_con()) {
999 uint shift = r2->get_con();
1000 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
1001 // Shift by a multiple of 32 does nothing:
1002 if (shift == 0) return t1;
1003 // Calculate reasonably aggressive bounds for the result.
1004 // This is necessary if we are to correctly type things
1005 // like (x<<24>>24) == ((byte)x).
1006 jint lo = (jint)r1->_lo >> (jint)shift;
1007 jint hi = (jint)r1->_hi >> (jint)shift;
1008 assert(lo <= hi, "must have valid bounds");
1009 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1010 #ifdef ASSERT
1011 // Make sure we get the sign-capture idiom correct.
1012 if (shift == BitsPerJavaInteger-1) {
1013 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>31 of + is 0");
1014 if (r1->_hi < 0) assert(ti == TypeInt::MINUS_1, ">>31 of - is -1");
1015 }
1016 #endif
1017 return ti;
1018 }
1019
1020 if( !r1->is_con() || !r2->is_con() )
1021 return TypeInt::INT;
1022
1023 // Signed shift right
1024 return TypeInt::make( r1->get_con() >> (r2->get_con()&31) );
1025 }
1026
1027 //=============================================================================
1028 //------------------------------Identity---------------------------------------
1029 Node *RShiftLNode::Identity( PhaseTransform *phase ) {
1030 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
1031 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
1032 }
1033
1034 //------------------------------Value------------------------------------------
1035 // A RShiftLNode shifts its input2 right by input1 amount.
1036 const Type *RShiftLNode::Value( PhaseTransform *phase ) const {
1037 const Type *t1 = phase->type( in(1) );
1038 const Type *t2 = phase->type( in(2) );
1039 // Either input is TOP ==> the result is TOP
1040 if( t1 == Type::TOP ) return Type::TOP;
1041 if( t2 == Type::TOP ) return Type::TOP;
1042
1043 // Left input is ZERO ==> the result is ZERO.
1044 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
1045 // Shift by zero does nothing
1046 if( t2 == TypeInt::ZERO ) return t1;
1047
1048 // Either input is BOTTOM ==> the result is BOTTOM
1049 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1050 return TypeLong::LONG;
1051
1052 if (t2 == TypeInt::INT)
1053 return TypeLong::LONG;
1054
1055 const TypeLong *r1 = t1->is_long(); // Handy access
1056 const TypeInt *r2 = t2->is_int (); // Handy access
1057
1058 // If the shift is a constant, just shift the bounds of the type.
1059 // For example, if the shift is 63, we just propagate sign bits.
1060 if (r2->is_con()) {
1061 uint shift = r2->get_con();
1062 shift &= (2*BitsPerJavaInteger)-1; // semantics of Java shifts
1063 // Shift by a multiple of 64 does nothing:
1064 if (shift == 0) return t1;
1065 // Calculate reasonably aggressive bounds for the result.
1066 // This is necessary if we are to correctly type things
1067 // like (x<<24>>24) == ((byte)x).
1068 jlong lo = (jlong)r1->_lo >> (jlong)shift;
1069 jlong hi = (jlong)r1->_hi >> (jlong)shift;
1070 assert(lo <= hi, "must have valid bounds");
1071 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1072 #ifdef ASSERT
1073 // Make sure we get the sign-capture idiom correct.
1074 if (shift == (2*BitsPerJavaInteger)-1) {
1075 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>63 of + is 0");
1076 if (r1->_hi < 0) assert(tl == TypeLong::MINUS_1, ">>63 of - is -1");
1077 }
1078 #endif
1079 return tl;
1080 }
1081
1082 return TypeLong::LONG; // Give up
1083 }
1084
1085 //=============================================================================
1086 //------------------------------Identity---------------------------------------
1087 Node *URShiftINode::Identity( PhaseTransform *phase ) {
1088 const TypeInt *ti = phase->type( in(2) )->isa_int();
1089 if ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerInt - 1 ) ) == 0 ) return in(1);
1090
1091 // Check for "((x << LogBytesPerWord) + (wordSize-1)) >> LogBytesPerWord" which is just "x".
1092 // Happens during new-array length computation.
1093 // Safe if 'x' is in the range [0..(max_int>>LogBytesPerWord)]
1094 Node *add = in(1);
1095 if( add->Opcode() == Op_AddI ) {
1096 const TypeInt *t2 = phase->type(add->in(2))->isa_int();
1097 if( t2 && t2->is_con(wordSize - 1) &&
1098 add->in(1)->Opcode() == Op_LShiftI ) {
1099 // Check that shift_counts are LogBytesPerWord
1100 Node *lshift_count = add->in(1)->in(2);
1101 const TypeInt *t_lshift_count = phase->type(lshift_count)->isa_int();
1102 if( t_lshift_count && t_lshift_count->is_con(LogBytesPerWord) &&
1103 t_lshift_count == phase->type(in(2)) ) {
1104 Node *x = add->in(1)->in(1);
1105 const TypeInt *t_x = phase->type(x)->isa_int();
1106 if( t_x != NULL && 0 <= t_x->_lo && t_x->_hi <= (max_jint>>LogBytesPerWord) ) {
1107 return x;
1108 }
1109 }
1110 }
1111 }
1112
1113 return (phase->type(in(2))->higher_equal(TypeInt::ZERO)) ? in(1) : this;
1114 }
1115
1116 //------------------------------Ideal------------------------------------------
1117 Node *URShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
1118 const TypeInt *t2 = phase->type( in(2) )->isa_int();
1119 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
1120 const int con = t2->get_con() & 31; // Shift count is always masked
1121 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count
1122 // We'll be wanting the right-shift amount as a mask of that many bits
1123 const int mask = right_n_bits(BitsPerJavaInteger - con);
1124
1125 int in1_op = in(1)->Opcode();
1126
1127 // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32
1128 if( in1_op == Op_URShiftI ) {
1129 const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int();
1130 if( t12 && t12->is_con() ) { // Right input is a constant
1131 assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" );
1132 const int con2 = t12->get_con() & 31; // Shift count is always masked
1133 const int con3 = con+con2;
1134 if( con3 < 32 ) // Only merge shifts if total is < 32
1135 return new (phase->C) URShiftINode( in(1)->in(1), phase->intcon(con3) );
1136 }
1137 }
1138
1139 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z
1140 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1141 // If Q is "X << z" the rounding is useless. Look for patterns like
1142 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask.
1143 Node *add = in(1);
1144 if( in1_op == Op_AddI ) {
1145 Node *lshl = add->in(1);
1146 if( lshl->Opcode() == Op_LShiftI &&
1147 phase->type(lshl->in(2)) == t2 ) {
1148 Node *y_z = phase->transform( new (phase->C) URShiftINode(add->in(2),in(2)) );
1149 Node *sum = phase->transform( new (phase->C) AddINode( lshl->in(1), y_z ) );
1150 return new (phase->C) AndINode( sum, phase->intcon(mask) );
1151 }
1152 }
1153
1154 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z)
1155 // This shortens the mask. Also, if we are extracting a high byte and
1156 // storing it to a buffer, the mask will be removed completely.
1157 Node *andi = in(1);
1158 if( in1_op == Op_AndI ) {
1159 const TypeInt *t3 = phase->type( andi->in(2) )->isa_int();
1160 if( t3 && t3->is_con() ) { // Right input is a constant
1161 jint mask2 = t3->get_con();
1162 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help)
1163 Node *newshr = phase->transform( new (phase->C) URShiftINode(andi->in(1), in(2)) );
1164 return new (phase->C) AndINode(newshr, phase->intcon(mask2));
1165 // The negative values are easier to materialize than positive ones.
1166 // A typical case from address arithmetic is ((x & ~15) >> 4).
1167 // It's better to change that to ((x >> 4) & ~0) versus
1168 // ((x >> 4) & 0x0FFFFFFF). The difference is greatest in LP64.
1169 }
1170 }
1171
1172 // Check for "(X << z ) >>> z" which simply zero-extends
1173 Node *shl = in(1);
1174 if( in1_op == Op_LShiftI &&
1175 phase->type(shl->in(2)) == t2 )
1176 return new (phase->C) AndINode( shl->in(1), phase->intcon(mask) );
1177
1178 return NULL;
1179 }
1180
1181 //------------------------------Value------------------------------------------
1182 // A URShiftINode shifts its input2 right by input1 amount.
1183 const Type *URShiftINode::Value( PhaseTransform *phase ) const {
1184 // (This is a near clone of RShiftINode::Value.)
1185 const Type *t1 = phase->type( in(1) );
1186 const Type *t2 = phase->type( in(2) );
1187 // Either input is TOP ==> the result is TOP
1188 if( t1 == Type::TOP ) return Type::TOP;
1189 if( t2 == Type::TOP ) return Type::TOP;
1190
1191 // Left input is ZERO ==> the result is ZERO.
1192 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
1193 // Shift by zero does nothing
1194 if( t2 == TypeInt::ZERO ) return t1;
1195
1196 // Either input is BOTTOM ==> the result is BOTTOM
1197 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1198 return TypeInt::INT;
1199
1200 if (t2 == TypeInt::INT)
1201 return TypeInt::INT;
1202
1203 const TypeInt *r1 = t1->is_int(); // Handy access
1204 const TypeInt *r2 = t2->is_int(); // Handy access
1205
1206 if (r2->is_con()) {
1207 uint shift = r2->get_con();
1208 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
1209 // Shift by a multiple of 32 does nothing:
1210 if (shift == 0) return t1;
1211 // Calculate reasonably aggressive bounds for the result.
1212 jint lo = (juint)r1->_lo >> (juint)shift;
1213 jint hi = (juint)r1->_hi >> (juint)shift;
1214 if (r1->_hi >= 0 && r1->_lo < 0) {
1215 // If the type has both negative and positive values,
1216 // there are two separate sub-domains to worry about:
1217 // The positive half and the negative half.
1218 jint neg_lo = lo;
1219 jint neg_hi = (juint)-1 >> (juint)shift;
1220 jint pos_lo = (juint) 0 >> (juint)shift;
1221 jint pos_hi = hi;
1222 lo = MIN2(neg_lo, pos_lo); // == 0
1223 hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift;
1224 }
1225 assert(lo <= hi, "must have valid bounds");
1226 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1227 #ifdef ASSERT
1228 // Make sure we get the sign-capture idiom correct.
1229 if (shift == BitsPerJavaInteger-1) {
1230 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0");
1231 if (r1->_hi < 0) assert(ti == TypeInt::ONE, ">>>31 of - is +1");
1232 }
1233 #endif
1234 return ti;
1235 }
1236
1237 //
1238 // Do not support shifted oops in info for GC
1239 //
1240 // else if( t1->base() == Type::InstPtr ) {
1241 //
1242 // const TypeInstPtr *o = t1->is_instptr();
1243 // if( t1->singleton() )
1244 // return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
1245 // }
1246 // else if( t1->base() == Type::KlassPtr ) {
1247 // const TypeKlassPtr *o = t1->is_klassptr();
1248 // if( t1->singleton() )
1249 // return TypeInt::make( ((uint32)o->const_oop() + o->_offset) >> shift );
1250 // }
1251
1252 return TypeInt::INT;
1253 }
1254
1255 //=============================================================================
1256 //------------------------------Identity---------------------------------------
1257 Node *URShiftLNode::Identity( PhaseTransform *phase ) {
1258 const TypeInt *ti = phase->type( in(2) )->isa_int(); // shift count is an int
1259 return ( ti && ti->is_con() && ( ti->get_con() & ( BitsPerLong - 1 ) ) == 0 ) ? in(1) : this;
1260 }
1261
1262 //------------------------------Ideal------------------------------------------
1263 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1264 const TypeInt *t2 = phase->type( in(2) )->isa_int();
1265 if( !t2 || !t2->is_con() ) return NULL; // Right input is a constant
1266 const int con = t2->get_con() & ( BitsPerLong - 1 ); // Shift count is always masked
1267 if ( con == 0 ) return NULL; // let Identity() handle a 0 shift count
1268 // note: mask computation below does not work for 0 shift count
1269 // We'll be wanting the right-shift amount as a mask of that many bits
1270 const jlong mask = jlong(max_julong >> con);
1271
1272 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z
1273 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1274 // If Q is "X << z" the rounding is useless. Look for patterns like
1275 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask.
1276 Node *add = in(1);
1277 if( add->Opcode() == Op_AddL ) {
1278 Node *lshl = add->in(1);
1279 if( lshl->Opcode() == Op_LShiftL &&
1280 phase->type(lshl->in(2)) == t2 ) {
1281 Node *y_z = phase->transform( new (phase->C) URShiftLNode(add->in(2),in(2)) );
1282 Node *sum = phase->transform( new (phase->C) AddLNode( lshl->in(1), y_z ) );
1283 return new (phase->C) AndLNode( sum, phase->longcon(mask) );
1284 }
1285 }
1286
1287 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z)
1288 // This shortens the mask. Also, if we are extracting a high byte and
1289 // storing it to a buffer, the mask will be removed completely.
1290 Node *andi = in(1);
1291 if( andi->Opcode() == Op_AndL ) {
1292 const TypeLong *t3 = phase->type( andi->in(2) )->isa_long();
1293 if( t3 && t3->is_con() ) { // Right input is a constant
1294 jlong mask2 = t3->get_con();
1295 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help)
1296 Node *newshr = phase->transform( new (phase->C) URShiftLNode(andi->in(1), in(2)) );
1297 return new (phase->C) AndLNode(newshr, phase->longcon(mask2));
1298 }
1299 }
1300
1301 // Check for "(X << z ) >>> z" which simply zero-extends
1302 Node *shl = in(1);
1303 if( shl->Opcode() == Op_LShiftL &&
1304 phase->type(shl->in(2)) == t2 )
1305 return new (phase->C) AndLNode( shl->in(1), phase->longcon(mask) );
1306
1307 return NULL;
1308 }
1309
1310 //------------------------------Value------------------------------------------
1311 // A URShiftINode shifts its input2 right by input1 amount.
1312 const Type *URShiftLNode::Value( PhaseTransform *phase ) const {
1313 // (This is a near clone of RShiftLNode::Value.)
1314 const Type *t1 = phase->type( in(1) );
1315 const Type *t2 = phase->type( in(2) );
1316 // Either input is TOP ==> the result is TOP
1317 if( t1 == Type::TOP ) return Type::TOP;
1318 if( t2 == Type::TOP ) return Type::TOP;
1319
1320 // Left input is ZERO ==> the result is ZERO.
1321 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
1322 // Shift by zero does nothing
1323 if( t2 == TypeInt::ZERO ) return t1;
1324
1325 // Either input is BOTTOM ==> the result is BOTTOM
1326 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1327 return TypeLong::LONG;
1328
1329 if (t2 == TypeInt::INT)
1330 return TypeLong::LONG;
1331
1332 const TypeLong *r1 = t1->is_long(); // Handy access
1333 const TypeInt *r2 = t2->is_int (); // Handy access
1334
1335 if (r2->is_con()) {
1336 uint shift = r2->get_con();
1337 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
1338 // Shift by a multiple of 64 does nothing:
1339 if (shift == 0) return t1;
1340 // Calculate reasonably aggressive bounds for the result.
1341 jlong lo = (julong)r1->_lo >> (juint)shift;
1342 jlong hi = (julong)r1->_hi >> (juint)shift;
1343 if (r1->_hi >= 0 && r1->_lo < 0) {
1344 // If the type has both negative and positive values,
1345 // there are two separate sub-domains to worry about:
1346 // The positive half and the negative half.
1347 jlong neg_lo = lo;
1348 jlong neg_hi = (julong)-1 >> (juint)shift;
1349 jlong pos_lo = (julong) 0 >> (juint)shift;
1350 jlong pos_hi = hi;
1351 //lo = MIN2(neg_lo, pos_lo); // == 0
1352 lo = neg_lo < pos_lo ? neg_lo : pos_lo;
1353 //hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift;
1354 hi = neg_hi > pos_hi ? neg_hi : pos_hi;
1355 }
1356 assert(lo <= hi, "must have valid bounds");
1357 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1358 #ifdef ASSERT
1359 // Make sure we get the sign-capture idiom correct.
1360 if (shift == BitsPerJavaLong - 1) {
1361 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0");
1362 if (r1->_hi < 0) assert(tl == TypeLong::ONE, ">>>63 of - is +1");
1363 }
1364 #endif
1365 return tl;
1366 }
1367
1368 return TypeLong::LONG; // Give up
1369 }