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comparison src/share/vm/c1/c1_Canonicalizer.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_c1_Canonicalizer.cpp.incl"
27
28
29 static void do_print_value(Value* vp) {
30 (*vp)->print_line();
31 }
32
33 void Canonicalizer::set_canonical(Value x) {
34 assert(x != NULL, "value must exist");
35 // Note: we can not currently substitute root nodes which show up in
36 // the instruction stream (because the instruction list is embedded
37 // in the instructions).
38 if (canonical() != x) {
39 if (PrintCanonicalization) {
40 canonical()->input_values_do(do_print_value);
41 canonical()->print_line();
42 tty->print_cr("canonicalized to:");
43 x->input_values_do(do_print_value);
44 x->print_line();
45 tty->cr();
46 }
47 assert(_canonical->type()->tag() == x->type()->tag(), "types must match");
48 _canonical = x;
49 }
50 }
51
52
53 void Canonicalizer::move_const_to_right(Op2* x) {
54 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands();
55 }
56
57
58 void Canonicalizer::do_Op2(Op2* x) {
59 if (x->x() == x->y()) {
60 switch (x->op()) {
61 case Bytecodes::_isub: set_constant(0); return;
62 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
63 case Bytecodes::_iand: // fall through
64 case Bytecodes::_land: // fall through
65 case Bytecodes::_ior: // fall through
66 case Bytecodes::_lor : set_canonical(x->x()); return;
67 case Bytecodes::_ixor: set_constant(0); return;
68 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
69 }
70 }
71
72 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
73 // do constant folding for selected operations
74 switch (x->type()->tag()) {
75 case intTag:
76 { jint a = x->x()->type()->as_IntConstant()->value();
77 jint b = x->y()->type()->as_IntConstant()->value();
78 switch (x->op()) {
79 case Bytecodes::_iadd: set_constant(a + b); return;
80 case Bytecodes::_isub: set_constant(a - b); return;
81 case Bytecodes::_imul: set_constant(a * b); return;
82 case Bytecodes::_idiv:
83 if (b != 0) {
84 if (a == min_jint && b == -1) {
85 set_constant(min_jint);
86 } else {
87 set_constant(a / b);
88 }
89 return;
90 }
91 break;
92 case Bytecodes::_irem:
93 if (b != 0) {
94 if (a == min_jint && b == -1) {
95 set_constant(0);
96 } else {
97 set_constant(a % b);
98 }
99 return;
100 }
101 break;
102 case Bytecodes::_iand: set_constant(a & b); return;
103 case Bytecodes::_ior : set_constant(a | b); return;
104 case Bytecodes::_ixor: set_constant(a ^ b); return;
105 }
106 }
107 break;
108 case longTag:
109 { jlong a = x->x()->type()->as_LongConstant()->value();
110 jlong b = x->y()->type()->as_LongConstant()->value();
111 switch (x->op()) {
112 case Bytecodes::_ladd: set_constant(a + b); return;
113 case Bytecodes::_lsub: set_constant(a - b); return;
114 case Bytecodes::_lmul: set_constant(a * b); return;
115 case Bytecodes::_ldiv:
116 if (b != 0) {
117 set_constant(SharedRuntime::ldiv(b, a));
118 return;
119 }
120 break;
121 case Bytecodes::_lrem:
122 if (b != 0) {
123 set_constant(SharedRuntime::lrem(b, a));
124 return;
125 }
126 break;
127 case Bytecodes::_land: set_constant(a & b); return;
128 case Bytecodes::_lor : set_constant(a | b); return;
129 case Bytecodes::_lxor: set_constant(a ^ b); return;
130 }
131 }
132 break;
133 // other cases not implemented (must be extremely careful with floats & doubles!)
134 }
135 }
136 // make sure constant is on the right side, if any
137 move_const_to_right(x);
138
139 if (x->y()->type()->is_constant()) {
140 // do constant folding for selected operations
141 switch (x->type()->tag()) {
142 case intTag:
143 if (x->y()->type()->as_IntConstant()->value() == 0) {
144 switch (x->op()) {
145 case Bytecodes::_iadd: set_canonical(x->x()); return;
146 case Bytecodes::_isub: set_canonical(x->x()); return;
147 case Bytecodes::_imul: set_constant(0); return;
148 // Note: for div and rem, make sure that C semantics
149 // corresponds to Java semantics!
150 case Bytecodes::_iand: set_constant(0); return;
151 case Bytecodes::_ior : set_canonical(x->x()); return;
152 }
153 }
154 break;
155 case longTag:
156 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
157 switch (x->op()) {
158 case Bytecodes::_ladd: set_canonical(x->x()); return;
159 case Bytecodes::_lsub: set_canonical(x->x()); return;
160 case Bytecodes::_lmul: set_constant((jlong)0); return;
161 // Note: for div and rem, make sure that C semantics
162 // corresponds to Java semantics!
163 case Bytecodes::_land: set_constant((jlong)0); return;
164 case Bytecodes::_lor : set_canonical(x->x()); return;
165 }
166 }
167 break;
168 }
169 }
170 }
171
172
173 void Canonicalizer::do_Phi (Phi* x) {}
174 void Canonicalizer::do_Constant (Constant* x) {}
175 void Canonicalizer::do_Local (Local* x) {}
176 void Canonicalizer::do_LoadField (LoadField* x) {}
177
178 // checks if v is in the block that is currently processed by
179 // GraphBuilder. This is the only block that has not BlockEnd yet.
180 static bool in_current_block(Value v) {
181 int max_distance = 4;
182 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
183 v = v->next();
184 max_distance--;
185 }
186 return v == NULL;
187 }
188
189 void Canonicalizer::do_StoreField (StoreField* x) {
190 // If a value is going to be stored into a field or array some of
191 // the conversions emitted by javac are unneeded because the fields
192 // are packed to their natural size.
193 Convert* conv = x->value()->as_Convert();
194 if (conv) {
195 Value value = NULL;
196 BasicType type = x->field()->type()->basic_type();
197 switch (conv->op()) {
198 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
199 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
200 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
201 }
202 // limit this optimization to current block
203 if (value != NULL && in_current_block(conv)) {
204 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
205 x->lock_stack(), x->state_before(), x->is_loaded(), x->is_initialized()));
206 return;
207 }
208 }
209
210 }
211
212 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
213 NewArray* array = x->array()->as_NewArray();
214 if (array != NULL && array->length() != NULL) {
215 Constant* length = array->length()->as_Constant();
216 if (length != NULL) {
217 // do not use the Constant itself, but create a new Constant
218 // with same value Otherwise a Constant is live over multiple
219 // blocks without being registered in a state array.
220 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
221 set_constant(length->type()->as_IntConstant()->value());
222 }
223 } else {
224 LoadField* lf = x->array()->as_LoadField();
225 if (lf != NULL && lf->field()->is_constant()) {
226 ciObject* c = lf->field()->constant_value().as_object();
227 if (c->is_array()) {
228 ciArray* array = (ciArray*) c;
229 set_constant(array->length());
230 }
231 }
232 }
233 }
234
235 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {}
236 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
237 // If a value is going to be stored into a field or array some of
238 // the conversions emitted by javac are unneeded because the fields
239 // are packed to their natural size.
240 Convert* conv = x->value()->as_Convert();
241 if (conv) {
242 Value value = NULL;
243 BasicType type = x->elt_type();
244 switch (conv->op()) {
245 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
246 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
247 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
248 }
249 // limit this optimization to current block
250 if (value != NULL && in_current_block(conv)) {
251 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
252 x->elt_type(), value, x->lock_stack()));
253 return;
254 }
255 }
256
257
258 }
259
260
261 void Canonicalizer::do_NegateOp(NegateOp* x) {
262 ValueType* t = x->x()->type();
263 if (t->is_constant()) {
264 switch (t->tag()) {
265 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
266 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
267 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
268 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
269 default : ShouldNotReachHere();
270 }
271 }
272 }
273
274
275 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
276
277
278 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
279 ValueType* t = x->x()->type();
280 ValueType* t2 = x->y()->type();
281 if (t->is_constant()) {
282 switch (t->tag()) {
283 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
284 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
285 default : ShouldNotReachHere();
286 }
287 if (t2->is_constant()) {
288 if (t->tag() == intTag) {
289 int value = t->as_IntConstant()->value();
290 int shift = t2->as_IntConstant()->value() & 31;
291 jint mask = ~(~0 << (32 - shift));
292 if (shift == 0) mask = ~0;
293 switch (x->op()) {
294 case Bytecodes::_ishl: set_constant(value << shift); return;
295 case Bytecodes::_ishr: set_constant(value >> shift); return;
296 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
297 }
298 } else if (t->tag() == longTag) {
299 jlong value = t->as_LongConstant()->value();
300 int shift = t2->as_IntConstant()->value() & 63;
301 jlong mask = ~(~jlong_cast(0) << (64 - shift));
302 if (shift == 0) mask = ~jlong_cast(0);
303 switch (x->op()) {
304 case Bytecodes::_lshl: set_constant(value << shift); return;
305 case Bytecodes::_lshr: set_constant(value >> shift); return;
306 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
307 }
308 }
309 }
310 }
311 if (t2->is_constant()) {
312 switch (t2->tag()) {
313 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
314 case longTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
315 default : ShouldNotReachHere();
316 }
317 }
318 }
319
320
321 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
322 void Canonicalizer::do_CompareOp (CompareOp* x) {
323 if (x->x() == x->y()) {
324 switch (x->x()->type()->tag()) {
325 case longTag: set_constant(0); break;
326 case floatTag: {
327 FloatConstant* fc = x->x()->type()->as_FloatConstant();
328 if (fc) {
329 if (g_isnan(fc->value())) {
330 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
331 } else {
332 set_constant(0);
333 }
334 }
335 break;
336 }
337 case doubleTag: {
338 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
339 if (dc) {
340 if (g_isnan(dc->value())) {
341 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
342 } else {
343 set_constant(0);
344 }
345 }
346 break;
347 }
348 }
349 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
350 switch (x->x()->type()->tag()) {
351 case longTag: {
352 jlong vx = x->x()->type()->as_LongConstant()->value();
353 jlong vy = x->y()->type()->as_LongConstant()->value();
354 if (vx == vy)
355 set_constant(0);
356 else if (vx < vy)
357 set_constant(-1);
358 else
359 set_constant(1);
360 break;
361 }
362
363 case floatTag: {
364 float vx = x->x()->type()->as_FloatConstant()->value();
365 float vy = x->y()->type()->as_FloatConstant()->value();
366 if (g_isnan(vx) || g_isnan(vy))
367 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
368 else if (vx == vy)
369 set_constant(0);
370 else if (vx < vy)
371 set_constant(-1);
372 else
373 set_constant(1);
374 break;
375 }
376
377 case doubleTag: {
378 double vx = x->x()->type()->as_DoubleConstant()->value();
379 double vy = x->y()->type()->as_DoubleConstant()->value();
380 if (g_isnan(vx) || g_isnan(vy))
381 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
382 else if (vx == vy)
383 set_constant(0);
384 else if (vx < vy)
385 set_constant(-1);
386 else
387 set_constant(1);
388 break;
389 }
390 }
391
392 }
393 }
394
395
396 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
397
398 void Canonicalizer::do_IfOp(IfOp* x) {
399 // Caution: do not use do_Op2(x) here for now since
400 // we map the condition to the op for now!
401 move_const_to_right(x);
402 }
403
404
405 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
406 switch (x->id()) {
407 case vmIntrinsics::_floatToRawIntBits : {
408 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
409 if (c != NULL) {
410 JavaValue v;
411 v.set_jfloat(c->value());
412 set_constant(v.get_jint());
413 }
414 break;
415 }
416 case vmIntrinsics::_intBitsToFloat : {
417 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
418 if (c != NULL) {
419 JavaValue v;
420 v.set_jint(c->value());
421 set_constant(v.get_jfloat());
422 }
423 break;
424 }
425 case vmIntrinsics::_doubleToRawLongBits : {
426 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
427 if (c != NULL) {
428 JavaValue v;
429 v.set_jdouble(c->value());
430 set_constant(v.get_jlong());
431 }
432 break;
433 }
434 case vmIntrinsics::_longBitsToDouble : {
435 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
436 if (c != NULL) {
437 JavaValue v;
438 v.set_jlong(c->value());
439 set_constant(v.get_jdouble());
440 }
441 break;
442 }
443 }
444 }
445
446 void Canonicalizer::do_Convert (Convert* x) {
447 if (x->value()->type()->is_constant()) {
448 switch (x->op()) {
449 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
450 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
451 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
452 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
453 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
454 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
455 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
456 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
457 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
458 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
459 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
460 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
461 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
462 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
463 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
464 default:
465 ShouldNotReachHere();
466 }
467 }
468
469 Value value = x->value();
470 BasicType type = T_ILLEGAL;
471 LoadField* lf = value->as_LoadField();
472 if (lf) {
473 type = lf->field_type();
474 } else {
475 LoadIndexed* li = value->as_LoadIndexed();
476 if (li) {
477 type = li->elt_type();
478 } else {
479 Convert* conv = value->as_Convert();
480 if (conv) {
481 switch (conv->op()) {
482 case Bytecodes::_i2b: type = T_BYTE; break;
483 case Bytecodes::_i2s: type = T_SHORT; break;
484 case Bytecodes::_i2c: type = T_CHAR; break;
485 }
486 }
487 }
488 }
489 if (type != T_ILLEGAL) {
490 switch (x->op()) {
491 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
492 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
493 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
494 }
495 } else {
496 Op2* op2 = x->value()->as_Op2();
497 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
498 jint safebits = 0;
499 jint mask = op2->y()->type()->as_IntConstant()->value();
500 switch (x->op()) {
501 case Bytecodes::_i2b: safebits = 0x7f; break;
502 case Bytecodes::_i2s: safebits = 0x7fff; break;
503 case Bytecodes::_i2c: safebits = 0xffff; break;
504 }
505 // When casting a masked integer to a smaller signed type, if
506 // the mask doesn't include the sign bit the cast isn't needed.
507 if (safebits && (mask & ~safebits) == 0) {
508 set_canonical(x->value());
509 }
510 }
511 }
512
513 }
514
515 void Canonicalizer::do_NullCheck (NullCheck* x) {
516 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
517 set_canonical(x->obj());
518 } else {
519 Constant* con = x->obj()->as_Constant();
520 if (con) {
521 ObjectType* c = con->type()->as_ObjectType();
522 if (c && c->is_loaded()) {
523 ObjectConstant* oc = c->as_ObjectConstant();
524 if (!oc || !oc->value()->is_null_object()) {
525 set_canonical(con);
526 }
527 }
528 }
529 }
530 }
531
532 void Canonicalizer::do_Invoke (Invoke* x) {}
533 void Canonicalizer::do_NewInstance (NewInstance* x) {}
534 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
535 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
536 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
537 void Canonicalizer::do_CheckCast (CheckCast* x) {
538 if (x->klass()->is_loaded()) {
539 Value obj = x->obj();
540 ciType* klass = obj->exact_type();
541 if (klass == NULL) klass = obj->declared_type();
542 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
543 set_canonical(obj);
544 return;
545 }
546 // checkcast of null returns null
547 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
548 set_canonical(obj);
549 }
550 }
551 }
552 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
553 if (x->klass()->is_loaded()) {
554 Value obj = x->obj();
555 ciType* exact = obj->exact_type();
556 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
557 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
558 return;
559 }
560 // instanceof null returns false
561 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
562 set_constant(0);
563 }
564 }
565
566 }
567 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
568 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
569 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
570 void Canonicalizer::do_Goto (Goto* x) {}
571
572
573 static bool is_true(jlong x, If::Condition cond, jlong y) {
574 switch (cond) {
575 case If::eql: return x == y;
576 case If::neq: return x != y;
577 case If::lss: return x < y;
578 case If::leq: return x <= y;
579 case If::gtr: return x > y;
580 case If::geq: return x >= y;
581 }
582 ShouldNotReachHere();
583 return false;
584 }
585
586
587 void Canonicalizer::do_If(If* x) {
588 // move const to right
589 if (x->x()->type()->is_constant()) x->swap_operands();
590 // simplify
591 const Value l = x->x(); ValueType* lt = l->type();
592 const Value r = x->y(); ValueType* rt = r->type();
593
594 if (l == r && !lt->is_float_kind()) {
595 // pattern: If (a cond a) => simplify to Goto
596 BlockBegin* sux;
597 switch (x->cond()) {
598 case If::eql: sux = x->sux_for(true); break;
599 case If::neq: sux = x->sux_for(false); break;
600 case If::lss: sux = x->sux_for(false); break;
601 case If::leq: sux = x->sux_for(true); break;
602 case If::gtr: sux = x->sux_for(false); break;
603 case If::geq: sux = x->sux_for(true); break;
604 }
605 // If is a safepoint then the debug information should come from the state_before of the If.
606 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
607 return;
608 }
609
610 if (lt->is_constant() && rt->is_constant()) {
611 if (x->x()->as_Constant() != NULL) {
612 // pattern: If (lc cond rc) => simplify to: Goto
613 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
614 x->sux_for(true),
615 x->sux_for(false));
616 if (sux != NULL) {
617 // If is a safepoint then the debug information should come from the state_before of the If.
618 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
619 }
620 }
621 } else if (rt->as_IntConstant() != NULL) {
622 // pattern: If (l cond rc) => investigate further
623 const jint rc = rt->as_IntConstant()->value();
624 if (l->as_CompareOp() != NULL) {
625 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
626 CompareOp* cmp = l->as_CompareOp();
627 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
628 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
629 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
630 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
631 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
632 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
633 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
634 // lss_sux or gtr_sux.
635 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
636 // all successors identical => simplify to: Goto
637 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
638 } else {
639 // two successors differ and two successors are the same => simplify to: If (x cmp y)
640 // determine new condition & successors
641 If::Condition cond;
642 BlockBegin* tsux = NULL;
643 BlockBegin* fsux = NULL;
644 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
645 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
646 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
647 else { ShouldNotReachHere(); }
648 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
649 if (cmp->x() == cmp->y()) {
650 do_If(canon);
651 } else {
652 set_canonical(canon);
653 set_bci(cmp->bci());
654 }
655 }
656 } else if (l->as_InstanceOf() != NULL) {
657 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
658 // instruction in the graph (it is pinned). Need to fix this at some point.
659 return;
660 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
661 InstanceOf* inst = l->as_InstanceOf();
662 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
663 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
664 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
665 // both successors identical and klass is loaded => simplify to: Goto
666 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
667 } else {
668 // successors differ => simplify to: IfInstanceOf
669 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->bci(), is_inst_sux, no_inst_sux));
670 }
671 }
672 } else if (rt == objectNull && (l->as_NewInstance() || l->as_NewArray())) {
673 if (x->cond() == Instruction::eql) {
674 set_canonical(new Goto(x->fsux(), x->state_before(), x->is_safepoint()));
675 } else {
676 assert(x->cond() == Instruction::neq, "only other valid case");
677 set_canonical(new Goto(x->tsux(), x->state_before(), x->is_safepoint()));
678 }
679 }
680 }
681
682
683 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
684 if (x->tag()->type()->is_constant()) {
685 int v = x->tag()->type()->as_IntConstant()->value();
686 BlockBegin* sux = x->default_sux();
687 if (v >= x->lo_key() && v <= x->hi_key()) {
688 sux = x->sux_at(v - x->lo_key());
689 }
690 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
691 } else if (x->number_of_sux() == 1) {
692 // NOTE: Code permanently disabled for now since the switch statement's
693 // tag expression may produce side-effects in which case it must
694 // be executed.
695 return;
696 // simplify to Goto
697 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
698 } else if (x->number_of_sux() == 2) {
699 // NOTE: Code permanently disabled for now since it produces two new nodes
700 // (Constant & If) and the Canonicalizer cannot return them correctly
701 // yet. For now we copied the corresponding code directly into the
702 // GraphBuilder (i.e., we should never reach here).
703 return;
704 // simplify to If
705 assert(x->lo_key() == x->hi_key(), "keys must be the same");
706 Constant* key = new Constant(new IntConstant(x->lo_key()));
707 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
708 }
709 }
710
711
712 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
713 if (x->tag()->type()->is_constant()) {
714 int v = x->tag()->type()->as_IntConstant()->value();
715 BlockBegin* sux = x->default_sux();
716 for (int i = 0; i < x->length(); i++) {
717 if (v == x->key_at(i)) {
718 sux = x->sux_at(i);
719 }
720 }
721 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
722 } else if (x->number_of_sux() == 1) {
723 // NOTE: Code permanently disabled for now since the switch statement's
724 // tag expression may produce side-effects in which case it must
725 // be executed.
726 return;
727 // simplify to Goto
728 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
729 } else if (x->number_of_sux() == 2) {
730 // NOTE: Code permanently disabled for now since it produces two new nodes
731 // (Constant & If) and the Canonicalizer cannot return them correctly
732 // yet. For now we copied the corresponding code directly into the
733 // GraphBuilder (i.e., we should never reach here).
734 return;
735 // simplify to If
736 assert(x->length() == 1, "length must be the same");
737 Constant* key = new Constant(new IntConstant(x->key_at(0)));
738 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
739 }
740 }
741
742
743 void Canonicalizer::do_Return (Return* x) {}
744 void Canonicalizer::do_Throw (Throw* x) {}
745 void Canonicalizer::do_Base (Base* x) {}
746 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
747 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
748
749 static bool match_index_and_scale(Instruction* instr,
750 Instruction** index,
751 int* log2_scale,
752 Instruction** instr_to_unpin) {
753 *instr_to_unpin = NULL;
754
755 // Skip conversion ops
756 Convert* convert = instr->as_Convert();
757 if (convert != NULL) {
758 instr = convert->value();
759 }
760
761 ShiftOp* shift = instr->as_ShiftOp();
762 if (shift != NULL) {
763 if (shift->is_pinned()) {
764 *instr_to_unpin = shift;
765 }
766 // Constant shift value?
767 Constant* con = shift->y()->as_Constant();
768 if (con == NULL) return false;
769 // Well-known type and value?
770 IntConstant* val = con->type()->as_IntConstant();
771 if (val == NULL) return false;
772 if (shift->x()->type() != intType) return false;
773 *index = shift->x();
774 int tmp_scale = val->value();
775 if (tmp_scale >= 0 && tmp_scale < 4) {
776 *log2_scale = tmp_scale;
777 return true;
778 } else {
779 return false;
780 }
781 }
782
783 ArithmeticOp* arith = instr->as_ArithmeticOp();
784 if (arith != NULL) {
785 if (arith->is_pinned()) {
786 *instr_to_unpin = arith;
787 }
788 // Check for integer multiply
789 if (arith->op() == Bytecodes::_imul) {
790 // See if either arg is a known constant
791 Constant* con = arith->x()->as_Constant();
792 if (con != NULL) {
793 *index = arith->y();
794 } else {
795 con = arith->y()->as_Constant();
796 if (con == NULL) return false;
797 *index = arith->x();
798 }
799 if ((*index)->type() != intType) return false;
800 // Well-known type and value?
801 IntConstant* val = con->type()->as_IntConstant();
802 if (val == NULL) return false;
803 switch (val->value()) {
804 case 1: *log2_scale = 0; return true;
805 case 2: *log2_scale = 1; return true;
806 case 4: *log2_scale = 2; return true;
807 case 8: *log2_scale = 3; return true;
808 default: return false;
809 }
810 }
811 }
812
813 // Unknown instruction sequence; don't touch it
814 return false;
815 }
816
817
818 static bool match(UnsafeRawOp* x,
819 Instruction** base,
820 Instruction** index,
821 int* log2_scale) {
822 Instruction* instr_to_unpin = NULL;
823 ArithmeticOp* root = x->base()->as_ArithmeticOp();
824 if (root == NULL) return false;
825 // Limit ourselves to addition for now
826 if (root->op() != Bytecodes::_ladd) return false;
827 // Try to find shift or scale op
828 if (match_index_and_scale(root->y(), index, log2_scale, &instr_to_unpin)) {
829 *base = root->x();
830 } else if (match_index_and_scale(root->x(), index, log2_scale, &instr_to_unpin)) {
831 *base = root->y();
832 } else if (root->y()->as_Convert() != NULL) {
833 Convert* convert = root->y()->as_Convert();
834 if (convert->op() == Bytecodes::_i2l && convert->value()->type() == intType) {
835 // pick base and index, setting scale at 1
836 *base = root->x();
837 *index = convert->value();
838 *log2_scale = 0;
839 } else {
840 return false;
841 }
842 } else {
843 // doesn't match any expected sequences
844 return false;
845 }
846
847 // If the value is pinned then it will be always be computed so
848 // there's no profit to reshaping the expression.
849 return !root->is_pinned();
850 }
851
852
853 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
854 Instruction* base = NULL;
855 Instruction* index = NULL;
856 int log2_scale;
857
858 if (match(x, &base, &index, &log2_scale)) {
859 x->set_base(base);
860 x->set_index(index);
861 x->set_log2_scale(log2_scale);
862 if (PrintUnsafeOptimization) {
863 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
864 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
865 }
866 }
867 }
868
869 void Canonicalizer::do_RoundFP(RoundFP* x) {}
870 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
871 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
872 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
873 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
874 void Canonicalizer::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {}
875 void Canonicalizer::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
876 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
877 void Canonicalizer::do_ProfileCounter(ProfileCounter* x) {}