1 /*
2 * Copyright (c) 1999, 2010, 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 "incls/_precompiled.incl"
26 #include "incls/_c1_Canonicalizer.cpp.incl"
27
28
29 class PrintValueVisitor: public ValueVisitor {
30 void visit(Value* vp) {
31 (*vp)->print_line();
32 }
33 };
34
35 void Canonicalizer::set_canonical(Value x) {
36 assert(x != NULL, "value must exist");
37 // Note: we can not currently substitute root nodes which show up in
38 // the instruction stream (because the instruction list is embedded
39 // in the instructions).
40 if (canonical() != x) {
41 if (PrintCanonicalization) {
42 PrintValueVisitor do_print_value;
43 canonical()->input_values_do(&do_print_value);
44 canonical()->print_line();
45 tty->print_cr("canonicalized to:");
46 x->input_values_do(&do_print_value);
47 x->print_line();
48 tty->cr();
49 }
50 assert(_canonical->type()->tag() == x->type()->tag(), "types must match");
51 _canonical = x;
52 }
53 }
54
55
56 void Canonicalizer::move_const_to_right(Op2* x) {
57 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands();
58 }
59
60
61 void Canonicalizer::do_Op2(Op2* x) {
62 if (x->x() == x->y()) {
63 switch (x->op()) {
64 case Bytecodes::_isub: set_constant(0); return;
65 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
66 case Bytecodes::_iand: // fall through
67 case Bytecodes::_land: // fall through
68 case Bytecodes::_ior: // fall through
69 case Bytecodes::_lor : set_canonical(x->x()); return;
70 case Bytecodes::_ixor: set_constant(0); return;
71 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
72 }
73 }
74
75 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
76 // do constant folding for selected operations
77 switch (x->type()->tag()) {
78 case intTag:
79 { jint a = x->x()->type()->as_IntConstant()->value();
80 jint b = x->y()->type()->as_IntConstant()->value();
81 switch (x->op()) {
82 case Bytecodes::_iadd: set_constant(a + b); return;
83 case Bytecodes::_isub: set_constant(a - b); return;
84 case Bytecodes::_imul: set_constant(a * b); return;
85 case Bytecodes::_idiv:
86 if (b != 0) {
87 if (a == min_jint && b == -1) {
88 set_constant(min_jint);
89 } else {
90 set_constant(a / b);
91 }
92 return;
93 }
94 break;
95 case Bytecodes::_irem:
96 if (b != 0) {
97 if (a == min_jint && b == -1) {
98 set_constant(0);
99 } else {
100 set_constant(a % b);
101 }
102 return;
103 }
104 break;
105 case Bytecodes::_iand: set_constant(a & b); return;
106 case Bytecodes::_ior : set_constant(a | b); return;
107 case Bytecodes::_ixor: set_constant(a ^ b); return;
108 }
109 }
110 break;
111 case longTag:
112 { jlong a = x->x()->type()->as_LongConstant()->value();
113 jlong b = x->y()->type()->as_LongConstant()->value();
114 switch (x->op()) {
115 case Bytecodes::_ladd: set_constant(a + b); return;
116 case Bytecodes::_lsub: set_constant(a - b); return;
117 case Bytecodes::_lmul: set_constant(a * b); return;
118 case Bytecodes::_ldiv:
119 if (b != 0) {
120 set_constant(SharedRuntime::ldiv(b, a));
121 return;
122 }
123 break;
124 case Bytecodes::_lrem:
125 if (b != 0) {
126 set_constant(SharedRuntime::lrem(b, a));
127 return;
128 }
129 break;
130 case Bytecodes::_land: set_constant(a & b); return;
131 case Bytecodes::_lor : set_constant(a | b); return;
132 case Bytecodes::_lxor: set_constant(a ^ b); return;
133 }
134 }
135 break;
136 // other cases not implemented (must be extremely careful with floats & doubles!)
137 }
138 }
139 // make sure constant is on the right side, if any
140 move_const_to_right(x);
141
142 if (x->y()->type()->is_constant()) {
143 // do constant folding for selected operations
144 switch (x->type()->tag()) {
145 case intTag:
146 if (x->y()->type()->as_IntConstant()->value() == 0) {
147 switch (x->op()) {
148 case Bytecodes::_iadd: set_canonical(x->x()); return;
149 case Bytecodes::_isub: set_canonical(x->x()); return;
150 case Bytecodes::_imul: set_constant(0); return;
151 // Note: for div and rem, make sure that C semantics
152 // corresponds to Java semantics!
153 case Bytecodes::_iand: set_constant(0); return;
154 case Bytecodes::_ior : set_canonical(x->x()); return;
155 }
156 }
157 break;
158 case longTag:
159 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
160 switch (x->op()) {
161 case Bytecodes::_ladd: set_canonical(x->x()); return;
162 case Bytecodes::_lsub: set_canonical(x->x()); return;
163 case Bytecodes::_lmul: set_constant((jlong)0); return;
164 // Note: for div and rem, make sure that C semantics
165 // corresponds to Java semantics!
166 case Bytecodes::_land: set_constant((jlong)0); return;
167 case Bytecodes::_lor : set_canonical(x->x()); return;
168 }
169 }
170 break;
171 }
172 }
173 }
174
175
176 void Canonicalizer::do_Phi (Phi* x) {}
177 void Canonicalizer::do_Constant (Constant* x) {}
178 void Canonicalizer::do_Local (Local* x) {}
179 void Canonicalizer::do_LoadField (LoadField* x) {}
180
181 // checks if v is in the block that is currently processed by
182 // GraphBuilder. This is the only block that has not BlockEnd yet.
183 static bool in_current_block(Value v) {
184 int max_distance = 4;
185 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
186 v = v->next();
187 max_distance--;
188 }
189 return v == NULL;
190 }
191
192 void Canonicalizer::do_StoreField (StoreField* x) {
193 // If a value is going to be stored into a field or array some of
194 // the conversions emitted by javac are unneeded because the fields
195 // are packed to their natural size.
196 Convert* conv = x->value()->as_Convert();
197 if (conv) {
198 Value value = NULL;
199 BasicType type = x->field()->type()->basic_type();
200 switch (conv->op()) {
201 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
202 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
203 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
204 }
205 // limit this optimization to current block
206 if (value != NULL && in_current_block(conv)) {
207 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
208 x->state_before(), x->is_loaded(), x->is_initialized()));
209 return;
210 }
211 }
212
213 }
214
215 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
216 NewArray* array = x->array()->as_NewArray();
217 if (array != NULL && array->length() != NULL) {
218 Constant* length = array->length()->as_Constant();
219 if (length != NULL) {
220 // do not use the Constant itself, but create a new Constant
221 // with same value Otherwise a Constant is live over multiple
222 // blocks without being registered in a state array.
223 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
224 set_constant(length->type()->as_IntConstant()->value());
225 }
226 } else {
227 LoadField* lf = x->array()->as_LoadField();
228 if (lf != NULL) {
229 ciField* field = lf->field();
230 if (field->is_constant() && field->is_static()) {
231 // final static field
232 ciObject* c = field->constant_value().as_object();
233 if (c->is_array()) {
234 ciArray* array = (ciArray*) c;
235 set_constant(array->length());
236 }
237 }
238 }
239 }
240 }
241
242 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {}
243 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
244 // If a value is going to be stored into a field or array some of
245 // the conversions emitted by javac are unneeded because the fields
246 // are packed to their natural size.
247 Convert* conv = x->value()->as_Convert();
248 if (conv) {
249 Value value = NULL;
250 BasicType type = x->elt_type();
251 switch (conv->op()) {
252 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
253 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
254 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
255 }
256 // limit this optimization to current block
257 if (value != NULL && in_current_block(conv)) {
258 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
259 x->elt_type(), value, x->state_before()));
260 return;
261 }
262 }
263
264
265 }
266
267
268 void Canonicalizer::do_NegateOp(NegateOp* x) {
269 ValueType* t = x->x()->type();
270 if (t->is_constant()) {
271 switch (t->tag()) {
272 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
273 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
274 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
275 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
276 default : ShouldNotReachHere();
277 }
278 }
279 }
280
281
282 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
283
284
285 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
286 ValueType* t = x->x()->type();
287 ValueType* t2 = x->y()->type();
288 if (t->is_constant()) {
289 switch (t->tag()) {
290 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
291 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
292 default : ShouldNotReachHere();
293 }
294 if (t2->is_constant()) {
295 if (t->tag() == intTag) {
296 int value = t->as_IntConstant()->value();
297 int shift = t2->as_IntConstant()->value() & 31;
298 jint mask = ~(~0 << (32 - shift));
299 if (shift == 0) mask = ~0;
300 switch (x->op()) {
301 case Bytecodes::_ishl: set_constant(value << shift); return;
302 case Bytecodes::_ishr: set_constant(value >> shift); return;
303 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
304 }
305 } else if (t->tag() == longTag) {
306 jlong value = t->as_LongConstant()->value();
307 int shift = t2->as_IntConstant()->value() & 63;
308 jlong mask = ~(~jlong_cast(0) << (64 - shift));
309 if (shift == 0) mask = ~jlong_cast(0);
310 switch (x->op()) {
311 case Bytecodes::_lshl: set_constant(value << shift); return;
312 case Bytecodes::_lshr: set_constant(value >> shift); return;
313 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
314 }
315 }
316 }
317 }
318 if (t2->is_constant()) {
319 switch (t2->tag()) {
320 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
321 case longTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
322 default : ShouldNotReachHere();
323 }
324 }
325 }
326
327
328 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
329 void Canonicalizer::do_CompareOp (CompareOp* x) {
330 if (x->x() == x->y()) {
331 switch (x->x()->type()->tag()) {
332 case longTag: set_constant(0); break;
333 case floatTag: {
334 FloatConstant* fc = x->x()->type()->as_FloatConstant();
335 if (fc) {
336 if (g_isnan(fc->value())) {
337 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
338 } else {
339 set_constant(0);
340 }
341 }
342 break;
343 }
344 case doubleTag: {
345 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
346 if (dc) {
347 if (g_isnan(dc->value())) {
348 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
349 } else {
350 set_constant(0);
351 }
352 }
353 break;
354 }
355 }
356 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
357 switch (x->x()->type()->tag()) {
358 case longTag: {
359 jlong vx = x->x()->type()->as_LongConstant()->value();
360 jlong vy = x->y()->type()->as_LongConstant()->value();
361 if (vx == vy)
362 set_constant(0);
363 else if (vx < vy)
364 set_constant(-1);
365 else
366 set_constant(1);
367 break;
368 }
369
370 case floatTag: {
371 float vx = x->x()->type()->as_FloatConstant()->value();
372 float vy = x->y()->type()->as_FloatConstant()->value();
373 if (g_isnan(vx) || g_isnan(vy))
374 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
375 else if (vx == vy)
376 set_constant(0);
377 else if (vx < vy)
378 set_constant(-1);
379 else
380 set_constant(1);
381 break;
382 }
383
384 case doubleTag: {
385 double vx = x->x()->type()->as_DoubleConstant()->value();
386 double vy = x->y()->type()->as_DoubleConstant()->value();
387 if (g_isnan(vx) || g_isnan(vy))
388 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
389 else if (vx == vy)
390 set_constant(0);
391 else if (vx < vy)
392 set_constant(-1);
393 else
394 set_constant(1);
395 break;
396 }
397 }
398
399 }
400 }
401
402
403 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
404
405 void Canonicalizer::do_IfOp(IfOp* x) {
406 // Caution: do not use do_Op2(x) here for now since
407 // we map the condition to the op for now!
408 move_const_to_right(x);
409 }
410
411
412 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
413 switch (x->id()) {
414 case vmIntrinsics::_floatToRawIntBits : {
415 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
416 if (c != NULL) {
417 JavaValue v;
418 v.set_jfloat(c->value());
419 set_constant(v.get_jint());
420 }
421 break;
422 }
423 case vmIntrinsics::_intBitsToFloat : {
424 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
425 if (c != NULL) {
426 JavaValue v;
427 v.set_jint(c->value());
428 set_constant(v.get_jfloat());
429 }
430 break;
431 }
432 case vmIntrinsics::_doubleToRawLongBits : {
433 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
434 if (c != NULL) {
435 JavaValue v;
436 v.set_jdouble(c->value());
437 set_constant(v.get_jlong());
438 }
439 break;
440 }
441 case vmIntrinsics::_longBitsToDouble : {
442 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
443 if (c != NULL) {
444 JavaValue v;
445 v.set_jlong(c->value());
446 set_constant(v.get_jdouble());
447 }
448 break;
449 }
450 }
451 }
452
453 void Canonicalizer::do_Convert (Convert* x) {
454 if (x->value()->type()->is_constant()) {
455 switch (x->op()) {
456 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
457 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
458 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
459 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
460 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
461 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
462 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
463 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
464 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
465 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
466 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
467 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
468 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
469 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
470 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
471 default:
472 ShouldNotReachHere();
473 }
474 }
475
476 Value value = x->value();
477 BasicType type = T_ILLEGAL;
478 LoadField* lf = value->as_LoadField();
479 if (lf) {
480 type = lf->field_type();
481 } else {
482 LoadIndexed* li = value->as_LoadIndexed();
483 if (li) {
484 type = li->elt_type();
485 } else {
486 Convert* conv = value->as_Convert();
487 if (conv) {
488 switch (conv->op()) {
489 case Bytecodes::_i2b: type = T_BYTE; break;
490 case Bytecodes::_i2s: type = T_SHORT; break;
491 case Bytecodes::_i2c: type = T_CHAR; break;
492 }
493 }
494 }
495 }
496 if (type != T_ILLEGAL) {
497 switch (x->op()) {
498 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
499 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
500 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
501 }
502 } else {
503 Op2* op2 = x->value()->as_Op2();
504 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
505 jint safebits = 0;
506 jint mask = op2->y()->type()->as_IntConstant()->value();
507 switch (x->op()) {
508 case Bytecodes::_i2b: safebits = 0x7f; break;
509 case Bytecodes::_i2s: safebits = 0x7fff; break;
510 case Bytecodes::_i2c: safebits = 0xffff; break;
511 }
512 // When casting a masked integer to a smaller signed type, if
513 // the mask doesn't include the sign bit the cast isn't needed.
514 if (safebits && (mask & ~safebits) == 0) {
515 set_canonical(x->value());
516 }
517 }
518 }
519
520 }
521
522 void Canonicalizer::do_NullCheck (NullCheck* x) {
523 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
524 set_canonical(x->obj());
525 } else {
526 Constant* con = x->obj()->as_Constant();
527 if (con) {
528 ObjectType* c = con->type()->as_ObjectType();
529 if (c && c->is_loaded()) {
530 ObjectConstant* oc = c->as_ObjectConstant();
531 if (!oc || !oc->value()->is_null_object()) {
532 set_canonical(con);
533 }
534 }
535 }
536 }
537 }
538
539 void Canonicalizer::do_Invoke (Invoke* x) {}
540 void Canonicalizer::do_NewInstance (NewInstance* x) {}
541 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
542 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
543 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
544 void Canonicalizer::do_CheckCast (CheckCast* x) {
545 if (x->klass()->is_loaded()) {
546 Value obj = x->obj();
547 ciType* klass = obj->exact_type();
548 if (klass == NULL) klass = obj->declared_type();
549 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
550 set_canonical(obj);
551 return;
552 }
553 // checkcast of null returns null
554 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
555 set_canonical(obj);
556 }
557 }
558 }
559 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
560 if (x->klass()->is_loaded()) {
561 Value obj = x->obj();
562 ciType* exact = obj->exact_type();
563 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
564 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
565 return;
566 }
567 // instanceof null returns false
568 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
569 set_constant(0);
570 }
571 }
572
573 }
574 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
575 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
576 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
577 void Canonicalizer::do_Goto (Goto* x) {}
578
579
580 static bool is_true(jlong x, If::Condition cond, jlong y) {
581 switch (cond) {
582 case If::eql: return x == y;
583 case If::neq: return x != y;
584 case If::lss: return x < y;
585 case If::leq: return x <= y;
586 case If::gtr: return x > y;
587 case If::geq: return x >= y;
588 }
589 ShouldNotReachHere();
590 return false;
591 }
592
593
594 void Canonicalizer::do_If(If* x) {
595 // move const to right
596 if (x->x()->type()->is_constant()) x->swap_operands();
597 // simplify
598 const Value l = x->x(); ValueType* lt = l->type();
599 const Value r = x->y(); ValueType* rt = r->type();
600
601 if (l == r && !lt->is_float_kind()) {
602 // pattern: If (a cond a) => simplify to Goto
603 BlockBegin* sux;
604 switch (x->cond()) {
605 case If::eql: sux = x->sux_for(true); break;
606 case If::neq: sux = x->sux_for(false); break;
607 case If::lss: sux = x->sux_for(false); break;
608 case If::leq: sux = x->sux_for(true); break;
609 case If::gtr: sux = x->sux_for(false); break;
610 case If::geq: sux = x->sux_for(true); break;
611 }
612 // If is a safepoint then the debug information should come from the state_before of the If.
613 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
614 return;
615 }
616
617 if (lt->is_constant() && rt->is_constant()) {
618 if (x->x()->as_Constant() != NULL) {
619 // pattern: If (lc cond rc) => simplify to: Goto
620 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
621 x->sux_for(true),
622 x->sux_for(false));
623 if (sux != NULL) {
624 // If is a safepoint then the debug information should come from the state_before of the If.
625 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
626 }
627 }
628 } else if (rt->as_IntConstant() != NULL) {
629 // pattern: If (l cond rc) => investigate further
630 const jint rc = rt->as_IntConstant()->value();
631 if (l->as_CompareOp() != NULL) {
632 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
633 CompareOp* cmp = l->as_CompareOp();
634 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
635 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
636 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
637 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
638 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
639 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
640 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
641 // lss_sux or gtr_sux.
642 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
643 // all successors identical => simplify to: Goto
644 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
645 } else {
646 // two successors differ and two successors are the same => simplify to: If (x cmp y)
647 // determine new condition & successors
648 If::Condition cond;
649 BlockBegin* tsux = NULL;
650 BlockBegin* fsux = NULL;
651 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
652 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
653 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
654 else { ShouldNotReachHere(); }
655 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
656 if (cmp->x() == cmp->y()) {
657 do_If(canon);
658 } else {
659 if (compilation()->profile_branches()) {
660 // TODO: If profiling, leave floating point comparisons unoptimized.
661 // We currently do not support profiling of the unordered case.
662 switch(cmp->op()) {
663 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
664 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
665 set_canonical(x);
666 return;
667 }
668 }
669 set_canonical(canon);
670 set_bci(cmp->state_before()->bci());
671 }
672 }
673 } else if (l->as_InstanceOf() != NULL) {
674 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
675 // instruction in the graph (it is pinned). Need to fix this at some point.
676 // It should also be left in the graph when generating a profiled method version or Goto
677 // has to know that it was an InstanceOf.
678 return;
679 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
680 InstanceOf* inst = l->as_InstanceOf();
681 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
682 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
683 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
684 // both successors identical and klass is loaded => simplify to: Goto
685 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
686 } else {
687 // successors differ => simplify to: IfInstanceOf
688 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
689 }
690 }
691 } else if (rt == objectNull && (l->as_NewInstance() || l->as_NewArray())) {
692 if (x->cond() == Instruction::eql) {
693 set_canonical(new Goto(x->fsux(), x->state_before(), x->is_safepoint()));
694 } else {
695 assert(x->cond() == Instruction::neq, "only other valid case");
696 set_canonical(new Goto(x->tsux(), x->state_before(), x->is_safepoint()));
697 }
698 }
699 }
700
701
702 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
703 if (x->tag()->type()->is_constant()) {
704 int v = x->tag()->type()->as_IntConstant()->value();
705 BlockBegin* sux = x->default_sux();
706 if (v >= x->lo_key() && v <= x->hi_key()) {
707 sux = x->sux_at(v - x->lo_key());
708 }
709 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
710 } else if (x->number_of_sux() == 1) {
711 // NOTE: Code permanently disabled for now since the switch statement's
712 // tag expression may produce side-effects in which case it must
713 // be executed.
714 return;
715 // simplify to Goto
716 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
717 } else if (x->number_of_sux() == 2) {
718 // NOTE: Code permanently disabled for now since it produces two new nodes
719 // (Constant & If) and the Canonicalizer cannot return them correctly
720 // yet. For now we copied the corresponding code directly into the
721 // GraphBuilder (i.e., we should never reach here).
722 return;
723 // simplify to If
724 assert(x->lo_key() == x->hi_key(), "keys must be the same");
725 Constant* key = new Constant(new IntConstant(x->lo_key()));
726 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
727 }
728 }
729
730
731 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
732 if (x->tag()->type()->is_constant()) {
733 int v = x->tag()->type()->as_IntConstant()->value();
734 BlockBegin* sux = x->default_sux();
735 for (int i = 0; i < x->length(); i++) {
736 if (v == x->key_at(i)) {
737 sux = x->sux_at(i);
738 }
739 }
740 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
741 } else if (x->number_of_sux() == 1) {
742 // NOTE: Code permanently disabled for now since the switch statement's
743 // tag expression may produce side-effects in which case it must
744 // be executed.
745 return;
746 // simplify to Goto
747 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
748 } else if (x->number_of_sux() == 2) {
749 // NOTE: Code permanently disabled for now since it produces two new nodes
750 // (Constant & If) and the Canonicalizer cannot return them correctly
751 // yet. For now we copied the corresponding code directly into the
752 // GraphBuilder (i.e., we should never reach here).
753 return;
754 // simplify to If
755 assert(x->length() == 1, "length must be the same");
756 Constant* key = new Constant(new IntConstant(x->key_at(0)));
757 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
758 }
759 }
760
761
762 void Canonicalizer::do_Return (Return* x) {}
763 void Canonicalizer::do_Throw (Throw* x) {}
764 void Canonicalizer::do_Base (Base* x) {}
765 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
766 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
767
768 static bool match_index_and_scale(Instruction* instr,
769 Instruction** index,
770 int* log2_scale,
771 Instruction** instr_to_unpin) {
772 *instr_to_unpin = NULL;
773
774 // Skip conversion ops
775 Convert* convert = instr->as_Convert();
776 if (convert != NULL) {
777 instr = convert->value();
778 }
779
780 ShiftOp* shift = instr->as_ShiftOp();
781 if (shift != NULL) {
782 if (shift->is_pinned()) {
783 *instr_to_unpin = shift;
784 }
785 // Constant shift value?
786 Constant* con = shift->y()->as_Constant();
787 if (con == NULL) return false;
788 // Well-known type and value?
789 IntConstant* val = con->type()->as_IntConstant();
790 if (val == NULL) return false;
791 if (shift->x()->type() != intType) return false;
792 *index = shift->x();
793 int tmp_scale = val->value();
794 if (tmp_scale >= 0 && tmp_scale < 4) {
795 *log2_scale = tmp_scale;
796 return true;
797 } else {
798 return false;
799 }
800 }
801
802 ArithmeticOp* arith = instr->as_ArithmeticOp();
803 if (arith != NULL) {
804 if (arith->is_pinned()) {
805 *instr_to_unpin = arith;
806 }
807 // Check for integer multiply
808 if (arith->op() == Bytecodes::_imul) {
809 // See if either arg is a known constant
810 Constant* con = arith->x()->as_Constant();
811 if (con != NULL) {
812 *index = arith->y();
813 } else {
814 con = arith->y()->as_Constant();
815 if (con == NULL) return false;
816 *index = arith->x();
817 }
818 if ((*index)->type() != intType) return false;
819 // Well-known type and value?
820 IntConstant* val = con->type()->as_IntConstant();
821 if (val == NULL) return false;
822 switch (val->value()) {
823 case 1: *log2_scale = 0; return true;
824 case 2: *log2_scale = 1; return true;
825 case 4: *log2_scale = 2; return true;
826 case 8: *log2_scale = 3; return true;
827 default: return false;
828 }
829 }
830 }
831
832 // Unknown instruction sequence; don't touch it
833 return false;
834 }
835
836
837 static bool match(UnsafeRawOp* x,
838 Instruction** base,
839 Instruction** index,
840 int* log2_scale) {
841 Instruction* instr_to_unpin = NULL;
842 ArithmeticOp* root = x->base()->as_ArithmeticOp();
843 if (root == NULL) return false;
844 // Limit ourselves to addition for now
845 if (root->op() != Bytecodes::_ladd) return false;
846 // Try to find shift or scale op
847 if (match_index_and_scale(root->y(), index, log2_scale, &instr_to_unpin)) {
848 *base = root->x();
849 } else if (match_index_and_scale(root->x(), index, log2_scale, &instr_to_unpin)) {
850 *base = root->y();
851 } else if (root->y()->as_Convert() != NULL) {
852 Convert* convert = root->y()->as_Convert();
853 if (convert->op() == Bytecodes::_i2l && convert->value()->type() == intType) {
854 // pick base and index, setting scale at 1
855 *base = root->x();
856 *index = convert->value();
857 *log2_scale = 0;
858 } else {
859 return false;
860 }
861 } else {
862 // doesn't match any expected sequences
863 return false;
864 }
865
866 // If the value is pinned then it will be always be computed so
867 // there's no profit to reshaping the expression.
868 return !root->is_pinned();
869 }
870
871
872 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
873 Instruction* base = NULL;
874 Instruction* index = NULL;
875 int log2_scale;
876
877 if (match(x, &base, &index, &log2_scale)) {
878 x->set_base(base);
879 x->set_index(index);
880 x->set_log2_scale(log2_scale);
881 if (PrintUnsafeOptimization) {
882 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
883 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
884 }
885 }
886 }
887
888 void Canonicalizer::do_RoundFP(RoundFP* x) {}
889 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
890 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
891 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
892 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
893 void Canonicalizer::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {}
894 void Canonicalizer::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
895 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
896 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
897