1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/addnode.hpp"
28 #include "opto/connode.hpp"
29 #include "opto/convertnode.hpp"
30 #include "opto/memnode.hpp"
31 #include "opto/mulnode.hpp"
32 #include "opto/phaseX.hpp"
33 #include "opto/subnode.hpp"
34
35 // Portions of code courtesy of Clifford Click
36
37
38 //=============================================================================
39 //------------------------------hash-------------------------------------------
40 // Hash function over MulNodes. Needs to be commutative; i.e., I swap
41 // (commute) inputs to MulNodes willy-nilly so the hash function must return
42 // the same value in the presence of edge swapping.
43 uint MulNode::hash() const {
44 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
45 }
46
47 //------------------------------Identity---------------------------------------
48 // Multiplying a one preserves the other argument
49 Node* MulNode::Identity(PhaseGVN* phase) {
50 register const Type *one = mul_id(); // The multiplicative identity
51 if( phase->type( in(1) )->higher_equal( one ) ) return in(2);
52 if( phase->type( in(2) )->higher_equal( one ) ) return in(1);
53
54 return this;
55 }
56
57 //------------------------------Ideal------------------------------------------
58 // We also canonicalize the Node, moving constants to the right input,
59 // and flatten expressions (so that 1+x+2 becomes x+3).
60 Node *MulNode::Ideal(PhaseGVN *phase, bool can_reshape) {
61 const Type *t1 = phase->type( in(1) );
62 const Type *t2 = phase->type( in(2) );
63 Node *progress = NULL; // Progress flag
64 // We are OK if right is a constant, or right is a load and
65 // left is a non-constant.
66 if( !(t2->singleton() ||
67 (in(2)->is_Load() && !(t1->singleton() || in(1)->is_Load())) ) ) {
68 if( t1->singleton() || // Left input is a constant?
69 // Otherwise, sort inputs (commutativity) to help value numbering.
70 (in(1)->_idx > in(2)->_idx) ) {
71 swap_edges(1, 2);
72 const Type *t = t1;
73 t1 = t2;
74 t2 = t;
75 progress = this; // Made progress
76 }
77 }
78
79 // If the right input is a constant, and the left input is a product of a
80 // constant, flatten the expression tree.
81 uint op = Opcode();
82 if( t2->singleton() && // Right input is a constant?
83 op != Op_MulF && // Float & double cannot reassociate
84 op != Op_MulD ) {
85 if( t2 == Type::TOP ) return NULL;
86 Node *mul1 = in(1);
87 #ifdef ASSERT
88 // Check for dead loop
89 int op1 = mul1->Opcode();
90 if( phase->eqv( mul1, this ) || phase->eqv( in(2), this ) ||
91 ( op1 == mul_opcode() || op1 == add_opcode() ) &&
92 ( phase->eqv( mul1->in(1), this ) || phase->eqv( mul1->in(2), this ) ||
93 phase->eqv( mul1->in(1), mul1 ) || phase->eqv( mul1->in(2), mul1 ) ) )
94 assert(false, "dead loop in MulNode::Ideal");
95 #endif
96
97 if( mul1->Opcode() == mul_opcode() ) { // Left input is a multiply?
98 // Mul of a constant?
99 const Type *t12 = phase->type( mul1->in(2) );
100 if( t12->singleton() && t12 != Type::TOP) { // Left input is an add of a constant?
101 // Compute new constant; check for overflow
102 const Type *tcon01 = ((MulNode*)mul1)->mul_ring(t2,t12);
103 if( tcon01->singleton() ) {
104 // The Mul of the flattened expression
105 set_req(1, mul1->in(1));
106 set_req(2, phase->makecon( tcon01 ));
107 t2 = tcon01;
108 progress = this; // Made progress
109 }
110 }
111 }
112 // If the right input is a constant, and the left input is an add of a
113 // constant, flatten the tree: (X+con1)*con0 ==> X*con0 + con1*con0
114 const Node *add1 = in(1);
115 if( add1->Opcode() == add_opcode() ) { // Left input is an add?
116 // Add of a constant?
117 const Type *t12 = phase->type( add1->in(2) );
118 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
119 assert( add1->in(1) != add1, "dead loop in MulNode::Ideal" );
120 // Compute new constant; check for overflow
121 const Type *tcon01 = mul_ring(t2,t12);
122 if( tcon01->singleton() ) {
123
124 // Convert (X+con1)*con0 into X*con0
125 Node *mul = clone(); // mul = ()*con0
126 mul->set_req(1,add1->in(1)); // mul = X*con0
127 mul = phase->transform(mul);
128
129 Node *add2 = add1->clone();
130 add2->set_req(1, mul); // X*con0 + con0*con1
131 add2->set_req(2, phase->makecon(tcon01) );
132 progress = add2;
133 }
134 }
135 } // End of is left input an add
136 } // End of is right input a Mul
137
138 return progress;
139 }
140
141 //------------------------------Value-----------------------------------------
142 const Type* MulNode::Value(PhaseGVN* phase) const {
143 const Type *t1 = phase->type( in(1) );
144 const Type *t2 = phase->type( in(2) );
145 // Either input is TOP ==> the result is TOP
146 if( t1 == Type::TOP ) return Type::TOP;
147 if( t2 == Type::TOP ) return Type::TOP;
148
149 // Either input is ZERO ==> the result is ZERO.
150 // Not valid for floats or doubles since +0.0 * -0.0 --> +0.0
151 int op = Opcode();
152 if( op == Op_MulI || op == Op_AndI || op == Op_MulL || op == Op_AndL ) {
153 const Type *zero = add_id(); // The multiplicative zero
154 if( t1->higher_equal( zero ) ) return zero;
155 if( t2->higher_equal( zero ) ) return zero;
156 }
157
158 // Code pattern on return from a call that returns an __Value. Can
159 // be optimized away if the return value turns out to be an oop.
160 if (op == Op_AndX &&
161 in(1) != NULL &&
162 in(1)->Opcode() == Op_CastP2X &&
163 in(1)->in(1) != NULL &&
164 phase->type(in(1)->in(1))->isa_oopptr() &&
165 t2->isa_intptr_t()->_lo >= 0 &&
166 t2->isa_intptr_t()->_hi <= MinObjAlignmentInBytesMask) {
167 return add_id();
168 }
169
170 // Either input is BOTTOM ==> the result is the local BOTTOM
171 if( t1 == Type::BOTTOM || t2 == Type::BOTTOM )
172 return bottom_type();
173
174 #if defined(IA32)
175 // Can't trust native compilers to properly fold strict double
176 // multiplication with round-to-zero on this platform.
177 if (op == Op_MulD && phase->C->method()->is_strict()) {
178 return TypeD::DOUBLE;
179 }
180 #endif
181
182 return mul_ring(t1,t2); // Local flavor of type multiplication
183 }
184
185
186 //=============================================================================
187 //------------------------------Ideal------------------------------------------
188 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
189 Node *MulINode::Ideal(PhaseGVN *phase, bool can_reshape) {
190 // Swap constant to right
191 jint con;
192 if ((con = in(1)->find_int_con(0)) != 0) {
193 swap_edges(1, 2);
194 // Finish rest of method to use info in 'con'
195 } else if ((con = in(2)->find_int_con(0)) == 0) {
196 return MulNode::Ideal(phase, can_reshape);
197 }
198
199 // Now we have a constant Node on the right and the constant in con
200 if( con == 0 ) return NULL; // By zero is handled by Value call
201 if( con == 1 ) return NULL; // By one is handled by Identity call
202
203 // Check for negative constant; if so negate the final result
204 bool sign_flip = false;
205 if( con < 0 ) {
206 con = -con;
207 sign_flip = true;
208 }
209
210 // Get low bit; check for being the only bit
211 Node *res = NULL;
212 jint bit1 = con & -con; // Extract low bit
213 if( bit1 == con ) { // Found a power of 2?
214 res = new LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) );
215 } else {
216
217 // Check for constant with 2 bits set
218 jint bit2 = con-bit1;
219 bit2 = bit2 & -bit2; // Extract 2nd bit
220 if( bit2 + bit1 == con ) { // Found all bits in con?
221 Node *n1 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(bit1)) ) );
222 Node *n2 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(bit2)) ) );
223 res = new AddINode( n2, n1 );
224
225 } else if (is_power_of_2(con+1)) {
226 // Sleezy: power-of-2 -1. Next time be generic.
227 jint temp = (jint) (con + 1);
228 Node *n1 = phase->transform( new LShiftINode( in(1), phase->intcon(log2_intptr(temp)) ) );
229 res = new SubINode( n1, in(1) );
230 } else {
231 return MulNode::Ideal(phase, can_reshape);
232 }
233 }
234
235 if( sign_flip ) { // Need to negate result?
236 res = phase->transform(res);// Transform, before making the zero con
237 res = new SubINode(phase->intcon(0),res);
238 }
239
240 return res; // Return final result
241 }
242
243 //------------------------------mul_ring---------------------------------------
244 // Compute the product type of two integer ranges into this node.
245 const Type *MulINode::mul_ring(const Type *t0, const Type *t1) const {
246 const TypeInt *r0 = t0->is_int(); // Handy access
247 const TypeInt *r1 = t1->is_int();
248
249 // Fetch endpoints of all ranges
250 int32_t lo0 = r0->_lo;
251 double a = (double)lo0;
252 int32_t hi0 = r0->_hi;
253 double b = (double)hi0;
254 int32_t lo1 = r1->_lo;
255 double c = (double)lo1;
256 int32_t hi1 = r1->_hi;
257 double d = (double)hi1;
258
259 // Compute all endpoints & check for overflow
260 int32_t A = java_multiply(lo0, lo1);
261 if( (double)A != a*c ) return TypeInt::INT; // Overflow?
262 int32_t B = java_multiply(lo0, hi1);
263 if( (double)B != a*d ) return TypeInt::INT; // Overflow?
264 int32_t C = java_multiply(hi0, lo1);
265 if( (double)C != b*c ) return TypeInt::INT; // Overflow?
266 int32_t D = java_multiply(hi0, hi1);
267 if( (double)D != b*d ) return TypeInt::INT; // Overflow?
268
269 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
270 else { lo0 = B; hi0 = A; }
271 if( C < D ) {
272 if( C < lo0 ) lo0 = C;
273 if( D > hi0 ) hi0 = D;
274 } else {
275 if( D < lo0 ) lo0 = D;
276 if( C > hi0 ) hi0 = C;
277 }
278 return TypeInt::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
279 }
280
281
282 //=============================================================================
283 //------------------------------Ideal------------------------------------------
284 // Check for power-of-2 multiply, then try the regular MulNode::Ideal
285 Node *MulLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
286 // Swap constant to right
287 jlong con;
288 if ((con = in(1)->find_long_con(0)) != 0) {
289 swap_edges(1, 2);
290 // Finish rest of method to use info in 'con'
291 } else if ((con = in(2)->find_long_con(0)) == 0) {
292 return MulNode::Ideal(phase, can_reshape);
293 }
294
295 // Now we have a constant Node on the right and the constant in con
296 if( con == CONST64(0) ) return NULL; // By zero is handled by Value call
297 if( con == CONST64(1) ) return NULL; // By one is handled by Identity call
298
299 // Check for negative constant; if so negate the final result
300 bool sign_flip = false;
301 if( con < 0 ) {
302 con = -con;
303 sign_flip = true;
304 }
305
306 // Get low bit; check for being the only bit
307 Node *res = NULL;
308 jlong bit1 = con & -con; // Extract low bit
309 if( bit1 == con ) { // Found a power of 2?
310 res = new LShiftLNode( in(1), phase->intcon(log2_long(bit1)) );
311 } else {
312
313 // Check for constant with 2 bits set
314 jlong bit2 = con-bit1;
315 bit2 = bit2 & -bit2; // Extract 2nd bit
316 if( bit2 + bit1 == con ) { // Found all bits in con?
317 Node *n1 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(bit1)) ) );
318 Node *n2 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(bit2)) ) );
319 res = new AddLNode( n2, n1 );
320
321 } else if (is_power_of_2_long(con+1)) {
322 // Sleezy: power-of-2 -1. Next time be generic.
323 jlong temp = (jlong) (con + 1);
324 Node *n1 = phase->transform( new LShiftLNode( in(1), phase->intcon(log2_long(temp)) ) );
325 res = new SubLNode( n1, in(1) );
326 } else {
327 return MulNode::Ideal(phase, can_reshape);
328 }
329 }
330
331 if( sign_flip ) { // Need to negate result?
332 res = phase->transform(res);// Transform, before making the zero con
333 res = new SubLNode(phase->longcon(0),res);
334 }
335
336 return res; // Return final result
337 }
338
339 //------------------------------mul_ring---------------------------------------
340 // Compute the product type of two integer ranges into this node.
341 const Type *MulLNode::mul_ring(const Type *t0, const Type *t1) const {
342 const TypeLong *r0 = t0->is_long(); // Handy access
343 const TypeLong *r1 = t1->is_long();
344
345 // Fetch endpoints of all ranges
346 jlong lo0 = r0->_lo;
347 double a = (double)lo0;
348 jlong hi0 = r0->_hi;
349 double b = (double)hi0;
350 jlong lo1 = r1->_lo;
351 double c = (double)lo1;
352 jlong hi1 = r1->_hi;
353 double d = (double)hi1;
354
355 // Compute all endpoints & check for overflow
356 jlong A = java_multiply(lo0, lo1);
357 if( (double)A != a*c ) return TypeLong::LONG; // Overflow?
358 jlong B = java_multiply(lo0, hi1);
359 if( (double)B != a*d ) return TypeLong::LONG; // Overflow?
360 jlong C = java_multiply(hi0, lo1);
361 if( (double)C != b*c ) return TypeLong::LONG; // Overflow?
362 jlong D = java_multiply(hi0, hi1);
363 if( (double)D != b*d ) return TypeLong::LONG; // Overflow?
364
365 if( A < B ) { lo0 = A; hi0 = B; } // Sort range endpoints
366 else { lo0 = B; hi0 = A; }
367 if( C < D ) {
368 if( C < lo0 ) lo0 = C;
369 if( D > hi0 ) hi0 = D;
370 } else {
371 if( D < lo0 ) lo0 = D;
372 if( C > hi0 ) hi0 = C;
373 }
374 return TypeLong::make(lo0, hi0, MAX2(r0->_widen,r1->_widen));
375 }
376
377 //=============================================================================
378 //------------------------------mul_ring---------------------------------------
379 // Compute the product type of two double ranges into this node.
380 const Type *MulFNode::mul_ring(const Type *t0, const Type *t1) const {
381 if( t0 == Type::FLOAT || t1 == Type::FLOAT ) return Type::FLOAT;
382 return TypeF::make( t0->getf() * t1->getf() );
383 }
384
385 //=============================================================================
386 //------------------------------mul_ring---------------------------------------
387 // Compute the product type of two double ranges into this node.
388 const Type *MulDNode::mul_ring(const Type *t0, const Type *t1) const {
389 if( t0 == Type::DOUBLE || t1 == Type::DOUBLE ) return Type::DOUBLE;
390 // We must be multiplying 2 double constants.
391 return TypeD::make( t0->getd() * t1->getd() );
392 }
393
394 //=============================================================================
395 //------------------------------Value------------------------------------------
396 const Type* MulHiLNode::Value(PhaseGVN* phase) const {
397 // Either input is TOP ==> the result is TOP
398 const Type *t1 = phase->type( in(1) );
399 const Type *t2 = phase->type( in(2) );
400 if( t1 == Type::TOP ) return Type::TOP;
401 if( t2 == Type::TOP ) return Type::TOP;
402
403 // Either input is BOTTOM ==> the result is the local BOTTOM
404 const Type *bot = bottom_type();
405 if( (t1 == bot) || (t2 == bot) ||
406 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
407 return bot;
408
409 // It is not worth trying to constant fold this stuff!
410 return TypeLong::LONG;
411 }
412
413 //=============================================================================
414 //------------------------------mul_ring---------------------------------------
415 // Supplied function returns the product of the inputs IN THE CURRENT RING.
416 // For the logical operations the ring's MUL is really a logical AND function.
417 // This also type-checks the inputs for sanity. Guaranteed never to
418 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
419 const Type *AndINode::mul_ring( const Type *t0, const Type *t1 ) const {
420 const TypeInt *r0 = t0->is_int(); // Handy access
421 const TypeInt *r1 = t1->is_int();
422 int widen = MAX2(r0->_widen,r1->_widen);
423
424 // If either input is a constant, might be able to trim cases
425 if( !r0->is_con() && !r1->is_con() )
426 return TypeInt::INT; // No constants to be had
427
428 // Both constants? Return bits
429 if( r0->is_con() && r1->is_con() )
430 return TypeInt::make( r0->get_con() & r1->get_con() );
431
432 if( r0->is_con() && r0->get_con() > 0 )
433 return TypeInt::make(0, r0->get_con(), widen);
434
435 if( r1->is_con() && r1->get_con() > 0 )
436 return TypeInt::make(0, r1->get_con(), widen);
437
438 if( r0 == TypeInt::BOOL || r1 == TypeInt::BOOL ) {
439 return TypeInt::BOOL;
440 }
441
442 return TypeInt::INT; // No constants to be had
443 }
444
445 //------------------------------Identity---------------------------------------
446 // Masking off the high bits of an unsigned load is not required
447 Node* AndINode::Identity(PhaseGVN* phase) {
448
449 // x & x => x
450 if (phase->eqv(in(1), in(2))) return in(1);
451
452 Node* in1 = in(1);
453 uint op = in1->Opcode();
454 const TypeInt* t2 = phase->type(in(2))->isa_int();
455 if (t2 && t2->is_con()) {
456 int con = t2->get_con();
457 // Masking off high bits which are always zero is useless.
458 const TypeInt* t1 = phase->type( in(1) )->isa_int();
459 if (t1 != NULL && t1->_lo >= 0) {
460 jint t1_support = right_n_bits(1 + log2_intptr(t1->_hi));
461 if ((t1_support & con) == t1_support)
462 return in1;
463 }
464 // Masking off the high bits of a unsigned-shift-right is not
465 // needed either.
466 if (op == Op_URShiftI) {
467 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
468 if (t12 && t12->is_con()) { // Shift is by a constant
469 int shift = t12->get_con();
470 shift &= BitsPerJavaInteger - 1; // semantics of Java shifts
471 int mask = max_juint >> shift;
472 if ((mask & con) == mask) // If AND is useless, skip it
473 return in1;
474 }
475 }
476 }
477 return MulNode::Identity(phase);
478 }
479
480 //------------------------------Ideal------------------------------------------
481 Node *AndINode::Ideal(PhaseGVN *phase, bool can_reshape) {
482 // Special case constant AND mask
483 const TypeInt *t2 = phase->type( in(2) )->isa_int();
484 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
485 const int mask = t2->get_con();
486 Node *load = in(1);
487 uint lop = load->Opcode();
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 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 = load->as_Load()->convert_to_unsigned_load(*phase);
499 ldus = phase->transform(ldus);
500 return new AndINode(ldus, phase->intcon(mask & 0xFFFF));
501 }
502
503 // Masking sign bits off of a Byte? Do an unsigned byte load plus
504 // an and.
505 if (lop == Op_LoadB && (mask & 0xFFFFFF00) == 0) {
506 Node* ldub = load->as_Load()->convert_to_unsigned_load(*phase);
507 ldub = phase->transform(ldub);
508 return new AndINode(ldub, phase->intcon(mask));
509 }
510 }
511
512 // Masking off sign bits? Dont make them!
513 if( lop == Op_RShiftI ) {
514 const TypeInt *t12 = phase->type(load->in(2))->isa_int();
515 if( t12 && t12->is_con() ) { // Shift is by a constant
516 int shift = t12->get_con();
517 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
518 const int sign_bits_mask = ~right_n_bits(BitsPerJavaInteger - shift);
519 // If the AND'ing of the 2 masks has no bits, then only original shifted
520 // bits survive. NO sign-extension bits survive the maskings.
521 if( (sign_bits_mask & mask) == 0 ) {
522 // Use zero-fill shift instead
523 Node *zshift = phase->transform(new URShiftINode(load->in(1),load->in(2)));
524 return new AndINode( zshift, in(2) );
525 }
526 }
527 }
528
529 // Check for 'negate/and-1', a pattern emitted when someone asks for
530 // 'mod 2'. Negate leaves the low order bit unchanged (think: complement
531 // plus 1) and the mask is of the low order bit. Skip the negate.
532 if( lop == Op_SubI && mask == 1 && load->in(1) &&
533 phase->type(load->in(1)) == TypeInt::ZERO )
534 return new AndINode( load->in(2), in(2) );
535
536 return MulNode::Ideal(phase, can_reshape);
537 }
538
539 //=============================================================================
540 //------------------------------mul_ring---------------------------------------
541 // Supplied function returns the product of the inputs IN THE CURRENT RING.
542 // For the logical operations the ring's MUL is really a logical AND function.
543 // This also type-checks the inputs for sanity. Guaranteed never to
544 // be passed a TOP or BOTTOM type, these are filtered out by pre-check.
545 const Type *AndLNode::mul_ring( const Type *t0, const Type *t1 ) const {
546 const TypeLong *r0 = t0->is_long(); // Handy access
547 const TypeLong *r1 = t1->is_long();
548 int widen = MAX2(r0->_widen,r1->_widen);
549
550 // If either input is a constant, might be able to trim cases
551 if( !r0->is_con() && !r1->is_con() )
552 return TypeLong::LONG; // No constants to be had
553
554 // Both constants? Return bits
555 if( r0->is_con() && r1->is_con() )
556 return TypeLong::make( r0->get_con() & r1->get_con() );
557
558 if( r0->is_con() && r0->get_con() > 0 )
559 return TypeLong::make(CONST64(0), r0->get_con(), widen);
560
561 if( r1->is_con() && r1->get_con() > 0 )
562 return TypeLong::make(CONST64(0), r1->get_con(), widen);
563
564 return TypeLong::LONG; // No constants to be had
565 }
566
567 //------------------------------Identity---------------------------------------
568 // Masking off the high bits of an unsigned load is not required
569 Node* AndLNode::Identity(PhaseGVN* phase) {
570
571 // x & x => x
572 if (phase->eqv(in(1), in(2))) return in(1);
573
574 Node *usr = in(1);
575 const TypeLong *t2 = phase->type( in(2) )->isa_long();
576 if( t2 && t2->is_con() ) {
577 jlong con = t2->get_con();
578 // Masking off high bits which are always zero is useless.
579 const TypeLong* t1 = phase->type( in(1) )->isa_long();
580 if (t1 != NULL && t1->_lo >= 0) {
581 int bit_count = log2_long(t1->_hi) + 1;
582 jlong t1_support = jlong(max_julong >> (BitsPerJavaLong - bit_count));
583 if ((t1_support & con) == t1_support)
584 return usr;
585 }
586 uint lop = usr->Opcode();
587 // Masking off the high bits of a unsigned-shift-right is not
588 // needed either.
589 if( lop == Op_URShiftL ) {
590 const TypeInt *t12 = phase->type( usr->in(2) )->isa_int();
591 if( t12 && t12->is_con() ) { // Shift is by a constant
592 int shift = t12->get_con();
593 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
594 jlong mask = max_julong >> shift;
595 if( (mask&con) == mask ) // If AND is useless, skip it
596 return usr;
597 }
598 }
599 }
600 return MulNode::Identity(phase);
601 }
602
603 //------------------------------Ideal------------------------------------------
604 Node *AndLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
605 // Special case constant AND mask
606 const TypeLong *t2 = phase->type( in(2) )->isa_long();
607 if( !t2 || !t2->is_con() ) return MulNode::Ideal(phase, can_reshape);
608 const jlong mask = t2->get_con();
609
610 Node* in1 = in(1);
611 uint op = in1->Opcode();
612
613 // Are we masking a long that was converted from an int with a mask
614 // that fits in 32-bits? Commute them and use an AndINode. Don't
615 // convert masks which would cause a sign extension of the integer
616 // value. This check includes UI2L masks (0x00000000FFFFFFFF) which
617 // would be optimized away later in Identity.
618 if (op == Op_ConvI2L && (mask & UCONST64(0xFFFFFFFF80000000)) == 0) {
619 Node* andi = new AndINode(in1->in(1), phase->intcon(mask));
620 andi = phase->transform(andi);
621 return new ConvI2LNode(andi);
622 }
623
624 // Masking off sign bits? Dont make them!
625 if (op == Op_RShiftL) {
626 const TypeInt* t12 = phase->type(in1->in(2))->isa_int();
627 if( t12 && t12->is_con() ) { // Shift is by a constant
628 int shift = t12->get_con();
629 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
630 const jlong sign_bits_mask = ~(((jlong)CONST64(1) << (jlong)(BitsPerJavaLong - shift)) -1);
631 // If the AND'ing of the 2 masks has no bits, then only original shifted
632 // bits survive. NO sign-extension bits survive the maskings.
633 if( (sign_bits_mask & mask) == 0 ) {
634 // Use zero-fill shift instead
635 Node *zshift = phase->transform(new URShiftLNode(in1->in(1), in1->in(2)));
636 return new AndLNode(zshift, in(2));
637 }
638 }
639 }
640
641 return MulNode::Ideal(phase, can_reshape);
642 }
643
644 //=============================================================================
645
646 static int getShiftCon(PhaseGVN *phase, Node *shiftNode, int retVal) {
647 const Type *t = phase->type(shiftNode->in(2));
648 if (t == Type::TOP) return retVal; // Right input is dead.
649 const TypeInt *t2 = t->isa_int();
650 if (!t2 || !t2->is_con()) return retVal; // Right input is a constant.
651
652 return t2->get_con();
653 }
654
655 static int maskShiftAmount(PhaseGVN *phase, Node *shiftNode, int nBits) {
656 int shift = getShiftCon(phase, shiftNode, 0);
657 int maskedShift = shift & (nBits - 1);
658
659 if (maskedShift == 0) return 0; // Let Identity() handle 0 shift count.
660
661 if (shift != maskedShift) {
662 shiftNode->set_req(2, phase->intcon(maskedShift)); // Replace shift count with masked value.
663 phase->igvn_rehash_node_delayed(shiftNode);
664 }
665
666 return maskedShift;
667 }
668
669 //------------------------------Identity---------------------------------------
670 Node* LShiftINode::Identity(PhaseGVN* phase) {
671 return ((getShiftCon(phase, this, -1) & (BitsPerJavaInteger - 1)) == 0) ? in(1) : this;
672 }
673
674 //------------------------------Ideal------------------------------------------
675 // If the right input is a constant, and the left input is an add of a
676 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
677 Node *LShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
678 int con = maskShiftAmount(phase, this, BitsPerJavaInteger);
679 if (con == 0) {
680 return NULL;
681 }
682
683 // Left input is an add of a constant?
684 Node *add1 = in(1);
685 int add1_op = add1->Opcode();
686 if( add1_op == Op_AddI ) { // Left input is an add?
687 assert( add1 != add1->in(1), "dead loop in LShiftINode::Ideal" );
688 const TypeInt *t12 = phase->type(add1->in(2))->isa_int();
689 if( t12 && t12->is_con() ){ // Left input is an add of a con?
690 // Transform is legal, but check for profit. Avoid breaking 'i2s'
691 // and 'i2b' patterns which typically fold into 'StoreC/StoreB'.
692 if( con < 16 ) {
693 // Compute X << con0
694 Node *lsh = phase->transform( new LShiftINode( add1->in(1), in(2) ) );
695 // Compute X<<con0 + (con1<<con0)
696 return new AddINode( lsh, phase->intcon(t12->get_con() << con));
697 }
698 }
699 }
700
701 // Check for "(x>>c0)<<c0" which just masks off low bits
702 if( (add1_op == Op_RShiftI || add1_op == Op_URShiftI ) &&
703 add1->in(2) == in(2) )
704 // Convert to "(x & -(1<<c0))"
705 return new AndINode(add1->in(1),phase->intcon( -(1<<con)));
706
707 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
708 if( add1_op == Op_AndI ) {
709 Node *add2 = add1->in(1);
710 int add2_op = add2->Opcode();
711 if( (add2_op == Op_RShiftI || add2_op == Op_URShiftI ) &&
712 add2->in(2) == in(2) ) {
713 // Convert to "(x & (Y<<c0))"
714 Node *y_sh = phase->transform( new LShiftINode( add1->in(2), in(2) ) );
715 return new AndINode( add2->in(1), y_sh );
716 }
717 }
718
719 // Check for ((x & ((1<<(32-c0))-1)) << c0) which ANDs off high bits
720 // before shifting them away.
721 const jint bits_mask = right_n_bits(BitsPerJavaInteger-con);
722 if( add1_op == Op_AndI &&
723 phase->type(add1->in(2)) == TypeInt::make( bits_mask ) )
724 return new LShiftINode( add1->in(1), in(2) );
725
726 return NULL;
727 }
728
729 //------------------------------Value------------------------------------------
730 // A LShiftINode shifts its input2 left by input1 amount.
731 const Type* LShiftINode::Value(PhaseGVN* phase) const {
732 const Type *t1 = phase->type( in(1) );
733 const Type *t2 = phase->type( in(2) );
734 // Either input is TOP ==> the result is TOP
735 if( t1 == Type::TOP ) return Type::TOP;
736 if( t2 == Type::TOP ) return Type::TOP;
737
738 // Left input is ZERO ==> the result is ZERO.
739 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
740 // Shift by zero does nothing
741 if( t2 == TypeInt::ZERO ) return t1;
742
743 // Either input is BOTTOM ==> the result is BOTTOM
744 if( (t1 == TypeInt::INT) || (t2 == TypeInt::INT) ||
745 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
746 return TypeInt::INT;
747
748 const TypeInt *r1 = t1->is_int(); // Handy access
749 const TypeInt *r2 = t2->is_int(); // Handy access
750
751 if (!r2->is_con())
752 return TypeInt::INT;
753
754 uint shift = r2->get_con();
755 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
756 // Shift by a multiple of 32 does nothing:
757 if (shift == 0) return t1;
758
759 // If the shift is a constant, shift the bounds of the type,
760 // unless this could lead to an overflow.
761 if (!r1->is_con()) {
762 jint lo = r1->_lo, hi = r1->_hi;
763 if (((lo << shift) >> shift) == lo &&
764 ((hi << shift) >> shift) == hi) {
765 // No overflow. The range shifts up cleanly.
766 return TypeInt::make((jint)lo << (jint)shift,
767 (jint)hi << (jint)shift,
768 MAX2(r1->_widen,r2->_widen));
769 }
770 return TypeInt::INT;
771 }
772
773 return TypeInt::make( (jint)r1->get_con() << (jint)shift );
774 }
775
776 //=============================================================================
777 //------------------------------Identity---------------------------------------
778 Node* LShiftLNode::Identity(PhaseGVN* phase) {
779 return ((getShiftCon(phase, this, -1) & (BitsPerJavaLong - 1)) == 0) ? in(1) : this;
780 }
781
782 //------------------------------Ideal------------------------------------------
783 // If the right input is a constant, and the left input is an add of a
784 // constant, flatten the tree: (X+con1)<<con0 ==> X<<con0 + con1<<con0
785 Node *LShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
786 int con = maskShiftAmount(phase, this, BitsPerJavaLong);
787 if (con == 0) {
788 return NULL;
789 }
790
791 // Left input is an add of a constant?
792 Node *add1 = in(1);
793 int add1_op = add1->Opcode();
794 if( add1_op == Op_AddL ) { // Left input is an add?
795 // Avoid dead data cycles from dead loops
796 assert( add1 != add1->in(1), "dead loop in LShiftLNode::Ideal" );
797 const TypeLong *t12 = phase->type(add1->in(2))->isa_long();
798 if( t12 && t12->is_con() ){ // Left input is an add of a con?
799 // Compute X << con0
800 Node *lsh = phase->transform( new LShiftLNode( add1->in(1), in(2) ) );
801 // Compute X<<con0 + (con1<<con0)
802 return new AddLNode( lsh, phase->longcon(t12->get_con() << con));
803 }
804 }
805
806 // Check for "(x>>c0)<<c0" which just masks off low bits
807 if( (add1_op == Op_RShiftL || add1_op == Op_URShiftL ) &&
808 add1->in(2) == in(2) )
809 // Convert to "(x & -(1<<c0))"
810 return new AndLNode(add1->in(1),phase->longcon( -(CONST64(1)<<con)));
811
812 // Check for "((x>>c0) & Y)<<c0" which just masks off more low bits
813 if( add1_op == Op_AndL ) {
814 Node *add2 = add1->in(1);
815 int add2_op = add2->Opcode();
816 if( (add2_op == Op_RShiftL || add2_op == Op_URShiftL ) &&
817 add2->in(2) == in(2) ) {
818 // Convert to "(x & (Y<<c0))"
819 Node *y_sh = phase->transform( new LShiftLNode( add1->in(2), in(2) ) );
820 return new AndLNode( add2->in(1), y_sh );
821 }
822 }
823
824 // Check for ((x & ((CONST64(1)<<(64-c0))-1)) << c0) which ANDs off high bits
825 // before shifting them away.
826 const jlong bits_mask = jlong(max_julong >> con);
827 if( add1_op == Op_AndL &&
828 phase->type(add1->in(2)) == TypeLong::make( bits_mask ) )
829 return new LShiftLNode( add1->in(1), in(2) );
830
831 return NULL;
832 }
833
834 //------------------------------Value------------------------------------------
835 // A LShiftLNode shifts its input2 left by input1 amount.
836 const Type* LShiftLNode::Value(PhaseGVN* phase) const {
837 const Type *t1 = phase->type( in(1) );
838 const Type *t2 = phase->type( in(2) );
839 // Either input is TOP ==> the result is TOP
840 if( t1 == Type::TOP ) return Type::TOP;
841 if( t2 == Type::TOP ) return Type::TOP;
842
843 // Left input is ZERO ==> the result is ZERO.
844 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
845 // Shift by zero does nothing
846 if( t2 == TypeInt::ZERO ) return t1;
847
848 // Either input is BOTTOM ==> the result is BOTTOM
849 if( (t1 == TypeLong::LONG) || (t2 == TypeInt::INT) ||
850 (t1 == Type::BOTTOM) || (t2 == Type::BOTTOM) )
851 return TypeLong::LONG;
852
853 const TypeLong *r1 = t1->is_long(); // Handy access
854 const TypeInt *r2 = t2->is_int(); // Handy access
855
856 if (!r2->is_con())
857 return TypeLong::LONG;
858
859 uint shift = r2->get_con();
860 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
861 // Shift by a multiple of 64 does nothing:
862 if (shift == 0) return t1;
863
864 // If the shift is a constant, shift the bounds of the type,
865 // unless this could lead to an overflow.
866 if (!r1->is_con()) {
867 jlong lo = r1->_lo, hi = r1->_hi;
868 if (((lo << shift) >> shift) == lo &&
869 ((hi << shift) >> shift) == hi) {
870 // No overflow. The range shifts up cleanly.
871 return TypeLong::make((jlong)lo << (jint)shift,
872 (jlong)hi << (jint)shift,
873 MAX2(r1->_widen,r2->_widen));
874 }
875 return TypeLong::LONG;
876 }
877
878 return TypeLong::make( (jlong)r1->get_con() << (jint)shift );
879 }
880
881 //=============================================================================
882 //------------------------------Identity---------------------------------------
883 Node* RShiftINode::Identity(PhaseGVN* phase) {
884 int shift = getShiftCon(phase, this, -1);
885 if (shift == -1) return this;
886 if ((shift & (BitsPerJavaInteger - 1)) == 0) return in(1);
887
888 // Check for useless sign-masking
889 if (in(1)->Opcode() == Op_LShiftI &&
890 in(1)->req() == 3 &&
891 in(1)->in(2) == in(2)) {
892 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
893 // Compute masks for which this shifting doesn't change
894 int lo = (-1 << (BitsPerJavaInteger - ((uint)shift)-1)); // FFFF8000
895 int hi = ~lo; // 00007FFF
896 const TypeInt *t11 = phase->type(in(1)->in(1))->isa_int();
897 if (!t11) return this;
898 // Does actual value fit inside of mask?
899 if (lo <= t11->_lo && t11->_hi <= hi) {
900 return in(1)->in(1); // Then shifting is a nop
901 }
902 }
903
904 return this;
905 }
906
907 //------------------------------Ideal------------------------------------------
908 Node *RShiftINode::Ideal(PhaseGVN *phase, bool can_reshape) {
909 // Inputs may be TOP if they are dead.
910 const TypeInt *t1 = phase->type(in(1))->isa_int();
911 if (!t1) return NULL; // Left input is an integer
912 const TypeInt *t3; // type of in(1).in(2)
913 int shift = maskShiftAmount(phase, this, BitsPerJavaInteger);
914 if (shift == 0) {
915 return NULL;
916 }
917
918 // Check for (x & 0xFF000000) >> 24, whose mask can be made smaller.
919 // Such expressions arise normally from shift chains like (byte)(x >> 24).
920 const Node *mask = in(1);
921 if( mask->Opcode() == Op_AndI &&
922 (t3 = phase->type(mask->in(2))->isa_int()) &&
923 t3->is_con() ) {
924 Node *x = mask->in(1);
925 jint maskbits = t3->get_con();
926 // Convert to "(x >> shift) & (mask >> shift)"
927 Node *shr_nomask = phase->transform( new RShiftINode(mask->in(1), in(2)) );
928 return new AndINode(shr_nomask, phase->intcon( maskbits >> shift));
929 }
930
931 // Check for "(short[i] <<16)>>16" which simply sign-extends
932 const Node *shl = in(1);
933 if( shl->Opcode() != Op_LShiftI ) return NULL;
934
935 if( shift == 16 &&
936 (t3 = phase->type(shl->in(2))->isa_int()) &&
937 t3->is_con(16) ) {
938 Node *ld = shl->in(1);
939 if( ld->Opcode() == Op_LoadS ) {
940 // Sign extension is just useless here. Return a RShiftI of zero instead
941 // returning 'ld' directly. We cannot return an old Node directly as
942 // that is the job of 'Identity' calls and Identity calls only work on
943 // direct inputs ('ld' is an extra Node removed from 'this'). The
944 // combined optimization requires Identity only return direct inputs.
945 set_req(1, ld);
946 set_req(2, phase->intcon(0));
947 return this;
948 }
949 else if( can_reshape &&
950 ld->Opcode() == Op_LoadUS &&
951 ld->outcnt() == 1 && ld->unique_out() == shl)
952 // Replace zero-extension-load with sign-extension-load
953 return ld->as_Load()->convert_to_signed_load(*phase);
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(PhaseGVN* 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(PhaseGVN* 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() & (BitsPerJavaLong - 1)) == 0) ? in(1) : this;
1032 }
1033
1034 //------------------------------Value------------------------------------------
1035 // A RShiftLNode shifts its input2 right by input1 amount.
1036 const Type* RShiftLNode::Value(PhaseGVN* 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(PhaseGVN* phase) {
1088 int shift = getShiftCon(phase, this, -1);
1089 if ((shift & (BitsPerJavaInteger - 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 int con = maskShiftAmount(phase, this, BitsPerJavaInteger);
1119 if (con == 0) {
1120 return NULL;
1121 }
1122
1123 // We'll be wanting the right-shift amount as a mask of that many bits
1124 const int mask = right_n_bits(BitsPerJavaInteger - con);
1125
1126 int in1_op = in(1)->Opcode();
1127
1128 // Check for ((x>>>a)>>>b) and replace with (x>>>(a+b)) when a+b < 32
1129 if( in1_op == Op_URShiftI ) {
1130 const TypeInt *t12 = phase->type( in(1)->in(2) )->isa_int();
1131 if( t12 && t12->is_con() ) { // Right input is a constant
1132 assert( in(1) != in(1)->in(1), "dead loop in URShiftINode::Ideal" );
1133 const int con2 = t12->get_con() & 31; // Shift count is always masked
1134 const int con3 = con+con2;
1135 if( con3 < 32 ) // Only merge shifts if total is < 32
1136 return new URShiftINode( in(1)->in(1), phase->intcon(con3) );
1137 }
1138 }
1139
1140 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z
1141 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1142 // If Q is "X << z" the rounding is useless. Look for patterns like
1143 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask.
1144 Node *add = in(1);
1145 const TypeInt *t2 = phase->type(in(2))->isa_int();
1146 if (in1_op == Op_AddI) {
1147 Node *lshl = add->in(1);
1148 if( lshl->Opcode() == Op_LShiftI &&
1149 phase->type(lshl->in(2)) == t2 ) {
1150 Node *y_z = phase->transform( new URShiftINode(add->in(2),in(2)) );
1151 Node *sum = phase->transform( new AddINode( lshl->in(1), y_z ) );
1152 return new AndINode( sum, phase->intcon(mask) );
1153 }
1154 }
1155
1156 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z)
1157 // This shortens the mask. Also, if we are extracting a high byte and
1158 // storing it to a buffer, the mask will be removed completely.
1159 Node *andi = in(1);
1160 if( in1_op == Op_AndI ) {
1161 const TypeInt *t3 = phase->type( andi->in(2) )->isa_int();
1162 if( t3 && t3->is_con() ) { // Right input is a constant
1163 jint mask2 = t3->get_con();
1164 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help)
1165 Node *newshr = phase->transform( new URShiftINode(andi->in(1), in(2)) );
1166 return new AndINode(newshr, phase->intcon(mask2));
1167 // The negative values are easier to materialize than positive ones.
1168 // A typical case from address arithmetic is ((x & ~15) >> 4).
1169 // It's better to change that to ((x >> 4) & ~0) versus
1170 // ((x >> 4) & 0x0FFFFFFF). The difference is greatest in LP64.
1171 }
1172 }
1173
1174 // Check for "(X << z ) >>> z" which simply zero-extends
1175 Node *shl = in(1);
1176 if( in1_op == Op_LShiftI &&
1177 phase->type(shl->in(2)) == t2 )
1178 return new AndINode( shl->in(1), phase->intcon(mask) );
1179
1180 return NULL;
1181 }
1182
1183 //------------------------------Value------------------------------------------
1184 // A URShiftINode shifts its input2 right by input1 amount.
1185 const Type* URShiftINode::Value(PhaseGVN* phase) const {
1186 // (This is a near clone of RShiftINode::Value.)
1187 const Type *t1 = phase->type( in(1) );
1188 const Type *t2 = phase->type( in(2) );
1189 // Either input is TOP ==> the result is TOP
1190 if( t1 == Type::TOP ) return Type::TOP;
1191 if( t2 == Type::TOP ) return Type::TOP;
1192
1193 // Left input is ZERO ==> the result is ZERO.
1194 if( t1 == TypeInt::ZERO ) return TypeInt::ZERO;
1195 // Shift by zero does nothing
1196 if( t2 == TypeInt::ZERO ) return t1;
1197
1198 // Either input is BOTTOM ==> the result is BOTTOM
1199 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1200 return TypeInt::INT;
1201
1202 if (t2 == TypeInt::INT)
1203 return TypeInt::INT;
1204
1205 const TypeInt *r1 = t1->is_int(); // Handy access
1206 const TypeInt *r2 = t2->is_int(); // Handy access
1207
1208 if (r2->is_con()) {
1209 uint shift = r2->get_con();
1210 shift &= BitsPerJavaInteger-1; // semantics of Java shifts
1211 // Shift by a multiple of 32 does nothing:
1212 if (shift == 0) return t1;
1213 // Calculate reasonably aggressive bounds for the result.
1214 jint lo = (juint)r1->_lo >> (juint)shift;
1215 jint hi = (juint)r1->_hi >> (juint)shift;
1216 if (r1->_hi >= 0 && r1->_lo < 0) {
1217 // If the type has both negative and positive values,
1218 // there are two separate sub-domains to worry about:
1219 // The positive half and the negative half.
1220 jint neg_lo = lo;
1221 jint neg_hi = (juint)-1 >> (juint)shift;
1222 jint pos_lo = (juint) 0 >> (juint)shift;
1223 jint pos_hi = hi;
1224 lo = MIN2(neg_lo, pos_lo); // == 0
1225 hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift;
1226 }
1227 assert(lo <= hi, "must have valid bounds");
1228 const TypeInt* ti = TypeInt::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1229 #ifdef ASSERT
1230 // Make sure we get the sign-capture idiom correct.
1231 if (shift == BitsPerJavaInteger-1) {
1232 if (r1->_lo >= 0) assert(ti == TypeInt::ZERO, ">>>31 of + is 0");
1233 if (r1->_hi < 0) assert(ti == TypeInt::ONE, ">>>31 of - is +1");
1234 }
1235 #endif
1236 return ti;
1237 }
1238
1239 //
1240 // Do not support shifted oops in info for GC
1241 //
1242 // else if( t1->base() == Type::InstPtr ) {
1243 //
1244 // const TypeInstPtr *o = t1->is_instptr();
1245 // if( t1->singleton() )
1246 // return TypeInt::make( ((uint32_t)o->const_oop() + o->_offset) >> shift );
1247 // }
1248 // else if( t1->base() == Type::KlassPtr ) {
1249 // const TypeKlassPtr *o = t1->is_klassptr();
1250 // if( t1->singleton() )
1251 // return TypeInt::make( ((uint32_t)o->const_oop() + o->_offset) >> shift );
1252 // }
1253
1254 return TypeInt::INT;
1255 }
1256
1257 //=============================================================================
1258 //------------------------------Identity---------------------------------------
1259 Node* URShiftLNode::Identity(PhaseGVN* phase) {
1260 return ((getShiftCon(phase, this, -1) & (BitsPerJavaLong - 1)) == 0) ? in(1) : this;
1261 }
1262
1263 //------------------------------Ideal------------------------------------------
1264 Node *URShiftLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1265 int con = maskShiftAmount(phase, this, BitsPerJavaLong);
1266 if (con == 0) {
1267 return NULL;
1268 }
1269
1270 // We'll be wanting the right-shift amount as a mask of that many bits
1271 const jlong mask = jlong(max_julong >> con);
1272
1273 // Check for ((x << z) + Y) >>> z. Replace with x + con>>>z
1274 // The idiom for rounding to a power of 2 is "(Q+(2^z-1)) >>> z".
1275 // If Q is "X << z" the rounding is useless. Look for patterns like
1276 // ((X<<Z) + Y) >>> Z and replace with (X + Y>>>Z) & Z-mask.
1277 Node *add = in(1);
1278 const TypeInt *t2 = phase->type(in(2))->isa_int();
1279 if (add->Opcode() == Op_AddL) {
1280 Node *lshl = add->in(1);
1281 if( lshl->Opcode() == Op_LShiftL &&
1282 phase->type(lshl->in(2)) == t2 ) {
1283 Node *y_z = phase->transform( new URShiftLNode(add->in(2),in(2)) );
1284 Node *sum = phase->transform( new AddLNode( lshl->in(1), y_z ) );
1285 return new AndLNode( sum, phase->longcon(mask) );
1286 }
1287 }
1288
1289 // Check for (x & mask) >>> z. Replace with (x >>> z) & (mask >>> z)
1290 // This shortens the mask. Also, if we are extracting a high byte and
1291 // storing it to a buffer, the mask will be removed completely.
1292 Node *andi = in(1);
1293 if( andi->Opcode() == Op_AndL ) {
1294 const TypeLong *t3 = phase->type( andi->in(2) )->isa_long();
1295 if( t3 && t3->is_con() ) { // Right input is a constant
1296 jlong mask2 = t3->get_con();
1297 mask2 >>= con; // *signed* shift downward (high-order zeroes do not help)
1298 Node *newshr = phase->transform( new URShiftLNode(andi->in(1), in(2)) );
1299 return new AndLNode(newshr, phase->longcon(mask2));
1300 }
1301 }
1302
1303 // Check for "(X << z ) >>> z" which simply zero-extends
1304 Node *shl = in(1);
1305 if( shl->Opcode() == Op_LShiftL &&
1306 phase->type(shl->in(2)) == t2 )
1307 return new AndLNode( shl->in(1), phase->longcon(mask) );
1308
1309 return NULL;
1310 }
1311
1312 //------------------------------Value------------------------------------------
1313 // A URShiftINode shifts its input2 right by input1 amount.
1314 const Type* URShiftLNode::Value(PhaseGVN* phase) const {
1315 // (This is a near clone of RShiftLNode::Value.)
1316 const Type *t1 = phase->type( in(1) );
1317 const Type *t2 = phase->type( in(2) );
1318 // Either input is TOP ==> the result is TOP
1319 if( t1 == Type::TOP ) return Type::TOP;
1320 if( t2 == Type::TOP ) return Type::TOP;
1321
1322 // Left input is ZERO ==> the result is ZERO.
1323 if( t1 == TypeLong::ZERO ) return TypeLong::ZERO;
1324 // Shift by zero does nothing
1325 if( t2 == TypeInt::ZERO ) return t1;
1326
1327 // Either input is BOTTOM ==> the result is BOTTOM
1328 if (t1 == Type::BOTTOM || t2 == Type::BOTTOM)
1329 return TypeLong::LONG;
1330
1331 if (t2 == TypeInt::INT)
1332 return TypeLong::LONG;
1333
1334 const TypeLong *r1 = t1->is_long(); // Handy access
1335 const TypeInt *r2 = t2->is_int (); // Handy access
1336
1337 if (r2->is_con()) {
1338 uint shift = r2->get_con();
1339 shift &= BitsPerJavaLong - 1; // semantics of Java shifts
1340 // Shift by a multiple of 64 does nothing:
1341 if (shift == 0) return t1;
1342 // Calculate reasonably aggressive bounds for the result.
1343 jlong lo = (julong)r1->_lo >> (juint)shift;
1344 jlong hi = (julong)r1->_hi >> (juint)shift;
1345 if (r1->_hi >= 0 && r1->_lo < 0) {
1346 // If the type has both negative and positive values,
1347 // there are two separate sub-domains to worry about:
1348 // The positive half and the negative half.
1349 jlong neg_lo = lo;
1350 jlong neg_hi = (julong)-1 >> (juint)shift;
1351 jlong pos_lo = (julong) 0 >> (juint)shift;
1352 jlong pos_hi = hi;
1353 //lo = MIN2(neg_lo, pos_lo); // == 0
1354 lo = neg_lo < pos_lo ? neg_lo : pos_lo;
1355 //hi = MAX2(neg_hi, pos_hi); // == -1 >>> shift;
1356 hi = neg_hi > pos_hi ? neg_hi : pos_hi;
1357 }
1358 assert(lo <= hi, "must have valid bounds");
1359 const TypeLong* tl = TypeLong::make(lo, hi, MAX2(r1->_widen,r2->_widen));
1360 #ifdef ASSERT
1361 // Make sure we get the sign-capture idiom correct.
1362 if (shift == BitsPerJavaLong - 1) {
1363 if (r1->_lo >= 0) assert(tl == TypeLong::ZERO, ">>>63 of + is 0");
1364 if (r1->_hi < 0) assert(tl == TypeLong::ONE, ">>>63 of - is +1");
1365 }
1366 #endif
1367 return tl;
1368 }
1369
1370 return TypeLong::LONG; // Give up
1371 }
1372
1373 //=============================================================================
1374 //------------------------------Value------------------------------------------
1375 const Type* FmaDNode::Value(PhaseGVN* phase) const {
1376 const Type *t1 = phase->type(in(1));
1377 if (t1 == Type::TOP) return Type::TOP;
1378 if (t1->base() != Type::DoubleCon) return Type::DOUBLE;
1379 const Type *t2 = phase->type(in(2));
1380 if (t2 == Type::TOP) return Type::TOP;
1381 if (t2->base() != Type::DoubleCon) return Type::DOUBLE;
1382 const Type *t3 = phase->type(in(3));
1383 if (t3 == Type::TOP) return Type::TOP;
1384 if (t3->base() != Type::DoubleCon) return Type::DOUBLE;
1385 #ifndef __STDC_IEC_559__
1386 return Type::DOUBLE;
1387 #else
1388 double d1 = t1->getd();
1389 double d2 = t2->getd();
1390 double d3 = t3->getd();
1391 return TypeD::make(fma(d1, d2, d3));
1392 #endif
1393 }
1394
1395 //=============================================================================
1396 //------------------------------Value------------------------------------------
1397 const Type* FmaFNode::Value(PhaseGVN* phase) const {
1398 const Type *t1 = phase->type(in(1));
1399 if (t1 == Type::TOP) return Type::TOP;
1400 if (t1->base() != Type::FloatCon) return Type::FLOAT;
1401 const Type *t2 = phase->type(in(2));
1402 if (t2 == Type::TOP) return Type::TOP;
1403 if (t2->base() != Type::FloatCon) return Type::FLOAT;
1404 const Type *t3 = phase->type(in(3));
1405 if (t3 == Type::TOP) return Type::TOP;
1406 if (t3->base() != Type::FloatCon) return Type::FLOAT;
1407 #ifndef __STDC_IEC_559__
1408 return Type::FLOAT;
1409 #else
1410 float f1 = t1->getf();
1411 float f2 = t2->getf();
1412 float f3 = t3->getf();
1413 return TypeF::make(fma(f1, f2, f3));
1414 #endif
1415 }