1 /*
2 * Copyright (c) 1999, 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 "c1/c1_Canonicalizer.hpp"
27 #include "c1/c1_InstructionPrinter.hpp"
28 #include "c1/c1_ValueStack.hpp"
29 #include "ci/ciArray.hpp"
30 #include "runtime/sharedRuntime.hpp"
31
32
33 class PrintValueVisitor: public ValueVisitor {
34 void visit(Value* vp) {
35 (*vp)->print_line();
36 }
37 };
38
39 void Canonicalizer::set_canonical(Value x) {
40 assert(x != NULL, "value must exist");
41 // Note: we can not currently substitute root nodes which show up in
42 // the instruction stream (because the instruction list is embedded
43 // in the instructions).
44 if (canonical() != x) {
45 #ifndef PRODUCT
46 if (!x->has_printable_bci()) {
47 x->set_printable_bci(bci());
48 }
49 #endif
50 if (PrintCanonicalization) {
51 PrintValueVisitor do_print_value;
52 canonical()->input_values_do(&do_print_value);
53 canonical()->print_line();
54 tty->print_cr("canonicalized to:");
55 x->input_values_do(&do_print_value);
56 x->print_line();
57 tty->cr();
58 }
59 assert(_canonical->type()->tag() == x->type()->tag(), "types must match");
60 _canonical = x;
61 }
62 }
63
64
65 void Canonicalizer::move_const_to_right(Op2* x) {
66 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands();
67 }
68
69
70 void Canonicalizer::do_Op2(Op2* x) {
71 if (x->x() == x->y()) {
72 switch (x->op()) {
73 case Bytecodes::_isub: set_constant(0); return;
74 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
75 case Bytecodes::_iand: // fall through
76 case Bytecodes::_land: // fall through
77 case Bytecodes::_ior: // fall through
78 case Bytecodes::_lor : set_canonical(x->x()); return;
79 case Bytecodes::_ixor: set_constant(0); return;
80 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
81 }
82 }
83
84 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
85 // do constant folding for selected operations
86 switch (x->type()->tag()) {
87 case intTag:
88 { jint a = x->x()->type()->as_IntConstant()->value();
89 jint b = x->y()->type()->as_IntConstant()->value();
90 switch (x->op()) {
91 case Bytecodes::_iadd: set_constant(a + b); return;
92 case Bytecodes::_isub: set_constant(a - b); return;
93 case Bytecodes::_imul: set_constant(a * b); return;
94 case Bytecodes::_idiv:
95 if (b != 0) {
96 if (a == min_jint && b == -1) {
97 set_constant(min_jint);
98 } else {
99 set_constant(a / b);
100 }
101 return;
102 }
103 break;
104 case Bytecodes::_irem:
105 if (b != 0) {
106 if (a == min_jint && b == -1) {
107 set_constant(0);
108 } else {
109 set_constant(a % b);
110 }
111 return;
112 }
113 break;
114 case Bytecodes::_iand: set_constant(a & b); return;
115 case Bytecodes::_ior : set_constant(a | b); return;
116 case Bytecodes::_ixor: set_constant(a ^ b); return;
117 }
118 }
119 break;
120 case longTag:
121 { jlong a = x->x()->type()->as_LongConstant()->value();
122 jlong b = x->y()->type()->as_LongConstant()->value();
123 switch (x->op()) {
124 case Bytecodes::_ladd: set_constant(a + b); return;
125 case Bytecodes::_lsub: set_constant(a - b); return;
126 case Bytecodes::_lmul: set_constant(a * b); return;
127 case Bytecodes::_ldiv:
128 if (b != 0) {
129 set_constant(SharedRuntime::ldiv(b, a));
130 return;
131 }
132 break;
133 case Bytecodes::_lrem:
134 if (b != 0) {
135 set_constant(SharedRuntime::lrem(b, a));
136 return;
137 }
138 break;
139 case Bytecodes::_land: set_constant(a & b); return;
140 case Bytecodes::_lor : set_constant(a | b); return;
141 case Bytecodes::_lxor: set_constant(a ^ b); return;
142 }
143 }
144 break;
145 // other cases not implemented (must be extremely careful with floats & doubles!)
146 }
147 }
148 // make sure constant is on the right side, if any
149 move_const_to_right(x);
150
151 if (x->y()->type()->is_constant()) {
152 // do constant folding for selected operations
153 switch (x->type()->tag()) {
154 case intTag:
155 if (x->y()->type()->as_IntConstant()->value() == 0) {
156 switch (x->op()) {
157 case Bytecodes::_iadd: set_canonical(x->x()); return;
158 case Bytecodes::_isub: set_canonical(x->x()); return;
159 case Bytecodes::_imul: set_constant(0); return;
160 // Note: for div and rem, make sure that C semantics
161 // corresponds to Java semantics!
162 case Bytecodes::_iand: set_constant(0); return;
163 case Bytecodes::_ior : set_canonical(x->x()); return;
164 }
165 }
166 break;
167 case longTag:
168 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
169 switch (x->op()) {
170 case Bytecodes::_ladd: set_canonical(x->x()); return;
171 case Bytecodes::_lsub: set_canonical(x->x()); return;
172 case Bytecodes::_lmul: set_constant((jlong)0); return;
173 // Note: for div and rem, make sure that C semantics
174 // corresponds to Java semantics!
175 case Bytecodes::_land: set_constant((jlong)0); return;
176 case Bytecodes::_lor : set_canonical(x->x()); return;
177 }
178 }
179 break;
180 }
181 }
182 }
183
184
185 void Canonicalizer::do_Phi (Phi* x) {}
186 void Canonicalizer::do_Constant (Constant* x) {}
187 void Canonicalizer::do_Local (Local* x) {}
188 void Canonicalizer::do_LoadField (LoadField* x) {}
189
190 // checks if v is in the block that is currently processed by
191 // GraphBuilder. This is the only block that has not BlockEnd yet.
192 static bool in_current_block(Value v) {
193 int max_distance = 4;
194 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
195 v = v->next();
196 max_distance--;
197 }
198 return v == NULL;
199 }
200
201 void Canonicalizer::do_StoreField (StoreField* x) {
202 // If a value is going to be stored into a field or array some of
203 // the conversions emitted by javac are unneeded because the fields
204 // are packed to their natural size.
205 Convert* conv = x->value()->as_Convert();
206 if (conv) {
207 Value value = NULL;
208 BasicType type = x->field()->type()->basic_type();
209 switch (conv->op()) {
210 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
211 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
212 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
213 }
214 // limit this optimization to current block
215 if (value != NULL && in_current_block(conv)) {
216 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
217 x->state_before(), x->needs_patching()));
218 return;
219 }
220 }
221
222 }
223
224 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
225 NewArray* array = x->array()->as_NewArray();
226 if (array != NULL && array->length() != NULL) {
227 Constant* length = array->length()->as_Constant();
228 if (length != NULL) {
229 // do not use the Constant itself, but create a new Constant
230 // with same value Otherwise a Constant is live over multiple
231 // blocks without being registered in a state array.
232 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
233 set_constant(length->type()->as_IntConstant()->value());
234 }
235 } else {
236 LoadField* lf = x->array()->as_LoadField();
237 if (lf != NULL) {
238 ciField* field = lf->field();
239 if (field->is_constant() && field->is_static()) {
240 // final static field
241 ciObject* c = field->constant_value().as_object();
242 if (c->is_array()) {
243 ciArray* array = (ciArray*) c;
244 set_constant(array->length());
245 }
246 }
247 }
248 }
249 }
250
251 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {}
252 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
253 // If a value is going to be stored into a field or array some of
254 // the conversions emitted by javac are unneeded because the fields
255 // are packed to their natural size.
256 Convert* conv = x->value()->as_Convert();
257 if (conv) {
258 Value value = NULL;
259 BasicType type = x->elt_type();
260 switch (conv->op()) {
261 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
262 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
263 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
264 }
265 // limit this optimization to current block
266 if (value != NULL && in_current_block(conv)) {
267 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
268 x->elt_type(), value, x->state_before()));
269 return;
270 }
271 }
272
273
274 }
275
276
277 void Canonicalizer::do_NegateOp(NegateOp* x) {
278 ValueType* t = x->x()->type();
279 if (t->is_constant()) {
280 switch (t->tag()) {
281 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
282 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
283 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
284 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
285 default : ShouldNotReachHere();
286 }
287 }
288 }
289
290
291 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
292
293
294 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
295 ValueType* t = x->x()->type();
296 ValueType* t2 = x->y()->type();
297 if (t->is_constant()) {
298 switch (t->tag()) {
299 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
300 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
301 default : ShouldNotReachHere();
302 }
303 if (t2->is_constant()) {
304 if (t->tag() == intTag) {
305 int value = t->as_IntConstant()->value();
306 int shift = t2->as_IntConstant()->value() & 31;
307 jint mask = ~(~0 << (32 - shift));
308 if (shift == 0) mask = ~0;
309 switch (x->op()) {
310 case Bytecodes::_ishl: set_constant(value << shift); return;
311 case Bytecodes::_ishr: set_constant(value >> shift); return;
312 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
313 }
314 } else if (t->tag() == longTag) {
315 jlong value = t->as_LongConstant()->value();
316 int shift = t2->as_IntConstant()->value() & 63;
317 jlong mask = ~(~jlong_cast(0) << (64 - shift));
318 if (shift == 0) mask = ~jlong_cast(0);
319 switch (x->op()) {
320 case Bytecodes::_lshl: set_constant(value << shift); return;
321 case Bytecodes::_lshr: set_constant(value >> shift); return;
322 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
323 }
324 }
325 }
326 }
327 if (t2->is_constant()) {
328 switch (t2->tag()) {
329 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
330 case longTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
331 default : ShouldNotReachHere();
332 }
333 }
334 }
335
336
337 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
338 void Canonicalizer::do_CompareOp (CompareOp* x) {
339 if (x->x() == x->y()) {
340 switch (x->x()->type()->tag()) {
341 case longTag: set_constant(0); break;
342 case floatTag: {
343 FloatConstant* fc = x->x()->type()->as_FloatConstant();
344 if (fc) {
345 if (g_isnan(fc->value())) {
346 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
347 } else {
348 set_constant(0);
349 }
350 }
351 break;
352 }
353 case doubleTag: {
354 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
355 if (dc) {
356 if (g_isnan(dc->value())) {
357 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
358 } else {
359 set_constant(0);
360 }
361 }
362 break;
363 }
364 }
365 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
366 switch (x->x()->type()->tag()) {
367 case longTag: {
368 jlong vx = x->x()->type()->as_LongConstant()->value();
369 jlong vy = x->y()->type()->as_LongConstant()->value();
370 if (vx == vy)
371 set_constant(0);
372 else if (vx < vy)
373 set_constant(-1);
374 else
375 set_constant(1);
376 break;
377 }
378
379 case floatTag: {
380 float vx = x->x()->type()->as_FloatConstant()->value();
381 float vy = x->y()->type()->as_FloatConstant()->value();
382 if (g_isnan(vx) || g_isnan(vy))
383 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
384 else if (vx == vy)
385 set_constant(0);
386 else if (vx < vy)
387 set_constant(-1);
388 else
389 set_constant(1);
390 break;
391 }
392
393 case doubleTag: {
394 double vx = x->x()->type()->as_DoubleConstant()->value();
395 double vy = x->y()->type()->as_DoubleConstant()->value();
396 if (g_isnan(vx) || g_isnan(vy))
397 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
398 else if (vx == vy)
399 set_constant(0);
400 else if (vx < vy)
401 set_constant(-1);
402 else
403 set_constant(1);
404 break;
405 }
406 }
407
408 }
409 }
410
411
412 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
413
414 void Canonicalizer::do_IfOp(IfOp* x) {
415 // Caution: do not use do_Op2(x) here for now since
416 // we map the condition to the op for now!
417 move_const_to_right(x);
418 }
419
420
421 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
422 switch (x->id()) {
423 case vmIntrinsics::_floatToRawIntBits : {
424 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
425 if (c != NULL) {
426 JavaValue v;
427 v.set_jfloat(c->value());
428 set_constant(v.get_jint());
429 }
430 break;
431 }
432 case vmIntrinsics::_intBitsToFloat : {
433 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
434 if (c != NULL) {
435 JavaValue v;
436 v.set_jint(c->value());
437 set_constant(v.get_jfloat());
438 }
439 break;
440 }
441 case vmIntrinsics::_doubleToRawLongBits : {
442 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
443 if (c != NULL) {
444 JavaValue v;
445 v.set_jdouble(c->value());
446 set_constant(v.get_jlong());
447 }
448 break;
449 }
450 case vmIntrinsics::_longBitsToDouble : {
451 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
452 if (c != NULL) {
453 JavaValue v;
454 v.set_jlong(c->value());
455 set_constant(v.get_jdouble());
456 }
457 break;
458 }
459 case vmIntrinsics::_isInstance : {
460 assert(x->number_of_arguments() == 2, "wrong type");
461
462 InstanceConstant* c = x->argument_at(0)->type()->as_InstanceConstant();
463 if (c != NULL && !c->value()->is_null_object()) {
464 // ciInstance::java_mirror_type() returns non-NULL only for Java mirrors
465 ciType* t = c->value()->as_instance()->java_mirror_type();
466 if (t->is_klass()) {
467 // substitute cls.isInstance(obj) of a constant Class into
468 // an InstantOf instruction
469 InstanceOf* i = new InstanceOf(t->as_klass(), x->argument_at(1), x->state_before());
470 set_canonical(i);
471 // and try to canonicalize even further
472 do_InstanceOf(i);
473 } else {
474 assert(t->is_primitive_type(), "should be a primitive type");
475 // cls.isInstance(obj) always returns false for primitive classes
476 set_constant(0);
477 }
478 }
479 break;
480 }
481 }
482 }
483
484 void Canonicalizer::do_Convert (Convert* x) {
485 if (x->value()->type()->is_constant()) {
486 switch (x->op()) {
487 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
488 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
489 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
490 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
491 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
492 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
493 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
494 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
495 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
496 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
497 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
498 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
499 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
500 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
501 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
502 default:
503 ShouldNotReachHere();
504 }
505 }
506
507 Value value = x->value();
508 BasicType type = T_ILLEGAL;
509 LoadField* lf = value->as_LoadField();
510 if (lf) {
511 type = lf->field_type();
512 } else {
513 LoadIndexed* li = value->as_LoadIndexed();
514 if (li) {
515 type = li->elt_type();
516 } else {
517 Convert* conv = value->as_Convert();
518 if (conv) {
519 switch (conv->op()) {
520 case Bytecodes::_i2b: type = T_BYTE; break;
521 case Bytecodes::_i2s: type = T_SHORT; break;
522 case Bytecodes::_i2c: type = T_CHAR; break;
523 }
524 }
525 }
526 }
527 if (type != T_ILLEGAL) {
528 switch (x->op()) {
529 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
530 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
531 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
532 }
533 } else {
534 Op2* op2 = x->value()->as_Op2();
535 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
536 jint safebits = 0;
537 jint mask = op2->y()->type()->as_IntConstant()->value();
538 switch (x->op()) {
539 case Bytecodes::_i2b: safebits = 0x7f; break;
540 case Bytecodes::_i2s: safebits = 0x7fff; break;
541 case Bytecodes::_i2c: safebits = 0xffff; break;
542 }
543 // When casting a masked integer to a smaller signed type, if
544 // the mask doesn't include the sign bit the cast isn't needed.
545 if (safebits && (mask & ~safebits) == 0) {
546 set_canonical(x->value());
547 }
548 }
549 }
550
551 }
552
553 void Canonicalizer::do_NullCheck (NullCheck* x) {
554 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
555 set_canonical(x->obj());
556 } else {
557 Constant* con = x->obj()->as_Constant();
558 if (con) {
559 ObjectType* c = con->type()->as_ObjectType();
560 if (c && c->is_loaded()) {
561 ObjectConstant* oc = c->as_ObjectConstant();
562 if (!oc || !oc->value()->is_null_object()) {
563 set_canonical(con);
564 }
565 }
566 }
567 }
568 }
569
570 void Canonicalizer::do_TypeCast (TypeCast* x) {}
571 void Canonicalizer::do_Invoke (Invoke* x) {}
572 void Canonicalizer::do_NewInstance (NewInstance* x) {}
573 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
574 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
575 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
576 void Canonicalizer::do_CheckCast (CheckCast* x) {
577 if (x->klass()->is_loaded()) {
578 Value obj = x->obj();
579 ciType* klass = obj->exact_type();
580 if (klass == NULL) klass = obj->declared_type();
581 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
582 set_canonical(obj);
583 return;
584 }
585 // checkcast of null returns null
586 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
587 set_canonical(obj);
588 }
589 }
590 }
591 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
592 if (x->klass()->is_loaded()) {
593 Value obj = x->obj();
594 ciType* exact = obj->exact_type();
595 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
596 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
597 return;
598 }
599 // instanceof null returns false
600 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
601 set_constant(0);
602 }
603 }
604
605 }
606 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
607 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
608 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
609 void Canonicalizer::do_Goto (Goto* x) {}
610
611
612 static bool is_true(jlong x, If::Condition cond, jlong y) {
613 switch (cond) {
614 case If::eql: return x == y;
615 case If::neq: return x != y;
616 case If::lss: return x < y;
617 case If::leq: return x <= y;
618 case If::gtr: return x > y;
619 case If::geq: return x >= y;
620 }
621 ShouldNotReachHere();
622 return false;
623 }
624
625 static bool is_safepoint(BlockEnd* x, BlockBegin* sux) {
626 // An Instruction with multiple successors, x, is replaced by a Goto
627 // to a single successor, sux. Is a safepoint check needed = was the
628 // instruction being replaced a safepoint and the single remaining
629 // successor a back branch?
630 return x->is_safepoint() && (sux->bci() < x->state_before()->bci());
631 }
632
633 void Canonicalizer::do_If(If* x) {
634 // move const to right
635 if (x->x()->type()->is_constant()) x->swap_operands();
636 // simplify
637 const Value l = x->x(); ValueType* lt = l->type();
638 const Value r = x->y(); ValueType* rt = r->type();
639
640 if (l == r && !lt->is_float_kind()) {
641 // pattern: If (a cond a) => simplify to Goto
642 BlockBegin* sux;
643 switch (x->cond()) {
644 case If::eql: sux = x->sux_for(true); break;
645 case If::neq: sux = x->sux_for(false); break;
646 case If::lss: sux = x->sux_for(false); break;
647 case If::leq: sux = x->sux_for(true); break;
648 case If::gtr: sux = x->sux_for(false); break;
649 case If::geq: sux = x->sux_for(true); break;
650 }
651 // If is a safepoint then the debug information should come from the state_before of the If.
652 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
653 return;
654 }
655
656 if (lt->is_constant() && rt->is_constant()) {
657 if (x->x()->as_Constant() != NULL) {
658 // pattern: If (lc cond rc) => simplify to: Goto
659 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
660 x->sux_for(true),
661 x->sux_for(false));
662 if (sux != NULL) {
663 // If is a safepoint then the debug information should come from the state_before of the If.
664 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
665 }
666 }
667 } else if (rt->as_IntConstant() != NULL) {
668 // pattern: If (l cond rc) => investigate further
669 const jint rc = rt->as_IntConstant()->value();
670 if (l->as_CompareOp() != NULL) {
671 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
672 CompareOp* cmp = l->as_CompareOp();
673 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
674 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
675 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
676 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
677 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
678 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
679 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
680 // lss_sux or gtr_sux.
681 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
682 // all successors identical => simplify to: Goto
683 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
684 } else {
685 // two successors differ and two successors are the same => simplify to: If (x cmp y)
686 // determine new condition & successors
687 If::Condition cond;
688 BlockBegin* tsux = NULL;
689 BlockBegin* fsux = NULL;
690 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
691 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
692 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
693 else { ShouldNotReachHere(); }
694 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
695 if (cmp->x() == cmp->y()) {
696 do_If(canon);
697 } else {
698 if (compilation()->profile_branches()) {
699 // TODO: If profiling, leave floating point comparisons unoptimized.
700 // We currently do not support profiling of the unordered case.
701 switch(cmp->op()) {
702 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
703 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
704 set_canonical(x);
705 return;
706 }
707 }
708 set_bci(cmp->state_before()->bci());
709 set_canonical(canon);
710 }
711 }
712 } else if (l->as_InstanceOf() != NULL) {
713 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
714 // instruction in the graph (it is pinned). Need to fix this at some point.
715 // It should also be left in the graph when generating a profiled method version or Goto
716 // has to know that it was an InstanceOf.
717 return;
718 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
719 InstanceOf* inst = l->as_InstanceOf();
720 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
721 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
722 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
723 // both successors identical and klass is loaded => simplify to: Goto
724 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
725 } else {
726 // successors differ => simplify to: IfInstanceOf
727 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
728 }
729 }
730 } else if (rt == objectNull && (l->as_NewInstance() || l->as_NewArray())) {
731 if (x->cond() == Instruction::eql) {
732 BlockBegin* sux = x->fsux();
733 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
734 } else {
735 assert(x->cond() == Instruction::neq, "only other valid case");
736 BlockBegin* sux = x->tsux();
737 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
738 }
739 }
740 }
741
742
743 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
744 if (x->tag()->type()->is_constant()) {
745 int v = x->tag()->type()->as_IntConstant()->value();
746 BlockBegin* sux = x->default_sux();
747 if (v >= x->lo_key() && v <= x->hi_key()) {
748 sux = x->sux_at(v - x->lo_key());
749 }
750 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
751 } else if (x->number_of_sux() == 1) {
752 // NOTE: Code permanently disabled for now since the switch statement's
753 // tag expression may produce side-effects in which case it must
754 // be executed.
755 return;
756 // simplify to Goto
757 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
758 } else if (x->number_of_sux() == 2) {
759 // NOTE: Code permanently disabled for now since it produces two new nodes
760 // (Constant & If) and the Canonicalizer cannot return them correctly
761 // yet. For now we copied the corresponding code directly into the
762 // GraphBuilder (i.e., we should never reach here).
763 return;
764 // simplify to If
765 assert(x->lo_key() == x->hi_key(), "keys must be the same");
766 Constant* key = new Constant(new IntConstant(x->lo_key()));
767 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
768 }
769 }
770
771
772 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
773 if (x->tag()->type()->is_constant()) {
774 int v = x->tag()->type()->as_IntConstant()->value();
775 BlockBegin* sux = x->default_sux();
776 for (int i = 0; i < x->length(); i++) {
777 if (v == x->key_at(i)) {
778 sux = x->sux_at(i);
779 }
780 }
781 set_canonical(new Goto(sux, x->state_before(), is_safepoint(x, sux)));
782 } else if (x->number_of_sux() == 1) {
783 // NOTE: Code permanently disabled for now since the switch statement's
784 // tag expression may produce side-effects in which case it must
785 // be executed.
786 return;
787 // simplify to Goto
788 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
789 } else if (x->number_of_sux() == 2) {
790 // NOTE: Code permanently disabled for now since it produces two new nodes
791 // (Constant & If) and the Canonicalizer cannot return them correctly
792 // yet. For now we copied the corresponding code directly into the
793 // GraphBuilder (i.e., we should never reach here).
794 return;
795 // simplify to If
796 assert(x->length() == 1, "length must be the same");
797 Constant* key = new Constant(new IntConstant(x->key_at(0)));
798 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
799 }
800 }
801
802
803 void Canonicalizer::do_Return (Return* x) {}
804 void Canonicalizer::do_Throw (Throw* x) {}
805 void Canonicalizer::do_Base (Base* x) {}
806 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
807 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
808
809 static bool match_index_and_scale(Instruction* instr,
810 Instruction** index,
811 int* log2_scale,
812 Instruction** instr_to_unpin) {
813 *instr_to_unpin = NULL;
814
815 // Skip conversion ops
816 Convert* convert = instr->as_Convert();
817 if (convert != NULL) {
818 instr = convert->value();
819 }
820
821 ShiftOp* shift = instr->as_ShiftOp();
822 if (shift != NULL) {
823 if (shift->is_pinned()) {
824 *instr_to_unpin = shift;
825 }
826 // Constant shift value?
827 Constant* con = shift->y()->as_Constant();
828 if (con == NULL) return false;
829 // Well-known type and value?
830 IntConstant* val = con->type()->as_IntConstant();
831 if (val == NULL) return false;
832 if (shift->x()->type() != intType) return false;
833 *index = shift->x();
834 int tmp_scale = val->value();
835 if (tmp_scale >= 0 && tmp_scale < 4) {
836 *log2_scale = tmp_scale;
837 return true;
838 } else {
839 return false;
840 }
841 }
842
843 ArithmeticOp* arith = instr->as_ArithmeticOp();
844 if (arith != NULL) {
845 if (arith->is_pinned()) {
846 *instr_to_unpin = arith;
847 }
848 // Check for integer multiply
849 if (arith->op() == Bytecodes::_imul) {
850 // See if either arg is a known constant
851 Constant* con = arith->x()->as_Constant();
852 if (con != NULL) {
853 *index = arith->y();
854 } else {
855 con = arith->y()->as_Constant();
856 if (con == NULL) return false;
857 *index = arith->x();
858 }
859 if ((*index)->type() != intType) return false;
860 // Well-known type and value?
861 IntConstant* val = con->type()->as_IntConstant();
862 if (val == NULL) return false;
863 switch (val->value()) {
864 case 1: *log2_scale = 0; return true;
865 case 2: *log2_scale = 1; return true;
866 case 4: *log2_scale = 2; return true;
867 case 8: *log2_scale = 3; return true;
868 default: return false;
869 }
870 }
871 }
872
873 // Unknown instruction sequence; don't touch it
874 return false;
875 }
876
877
878 static bool match(UnsafeRawOp* x,
879 Instruction** base,
880 Instruction** index,
881 int* log2_scale) {
882 Instruction* instr_to_unpin = NULL;
883 ArithmeticOp* root = x->base()->as_ArithmeticOp();
884 if (root == NULL) return false;
885 // Limit ourselves to addition for now
886 if (root->op() != Bytecodes::_ladd) return false;
887 // Try to find shift or scale op
888 if (match_index_and_scale(root->y(), index, log2_scale, &instr_to_unpin)) {
889 *base = root->x();
890 } else if (match_index_and_scale(root->x(), index, log2_scale, &instr_to_unpin)) {
891 *base = root->y();
892 } else if (root->y()->as_Convert() != NULL) {
893 Convert* convert = root->y()->as_Convert();
894 if (convert->op() == Bytecodes::_i2l && convert->value()->type() == intType) {
895 // pick base and index, setting scale at 1
896 *base = root->x();
897 *index = convert->value();
898 *log2_scale = 0;
899 } else {
900 return false;
901 }
902 } else {
903 // doesn't match any expected sequences
904 return false;
905 }
906
907 // If the value is pinned then it will be always be computed so
908 // there's no profit to reshaping the expression.
909 return !root->is_pinned();
910 }
911
912
913 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
914 Instruction* base = NULL;
915 Instruction* index = NULL;
916 int log2_scale;
917
918 if (match(x, &base, &index, &log2_scale)) {
919 x->set_base(base);
920 x->set_index(index);
921 x->set_log2_scale(log2_scale);
922 if (PrintUnsafeOptimization) {
923 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
924 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
925 }
926 }
927 }
928
929 void Canonicalizer::do_RoundFP(RoundFP* x) {}
930 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
931 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
932 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
933 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
934 void Canonicalizer::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
935 void Canonicalizer::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {}
936 void Canonicalizer::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
937 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
938 void Canonicalizer::do_ProfileReturnType(ProfileReturnType* x) {}
939 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
940 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}
941 void Canonicalizer::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
942 #ifdef ASSERT
943 void Canonicalizer::do_Assert(Assert* x) {}
944 #endif
945 void Canonicalizer::do_MemBar(MemBar* x) {}