1 /*
2 * Copyright (c) 1999, 2011, 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 if (PrintCanonicalization) {
46 PrintValueVisitor do_print_value;
47 canonical()->input_values_do(&do_print_value);
48 canonical()->print_line();
49 tty->print_cr("canonicalized to:");
50 x->input_values_do(&do_print_value);
51 x->print_line();
52 tty->cr();
53 }
54 assert(_canonical->type()->tag() == x->type()->tag(), "types must match");
55 _canonical = x;
56 }
57 }
58
59
60 void Canonicalizer::move_const_to_right(Op2* x) {
61 if (x->x()->type()->is_constant() && x->is_commutative()) x->swap_operands();
62 }
63
64
65 void Canonicalizer::do_Op2(Op2* x) {
66 if (x->x() == x->y()) {
67 switch (x->op()) {
68 case Bytecodes::_isub: set_constant(0); return;
69 case Bytecodes::_lsub: set_constant(jlong_cast(0)); return;
70 case Bytecodes::_iand: // fall through
71 case Bytecodes::_land: // fall through
72 case Bytecodes::_ior: // fall through
73 case Bytecodes::_lor : set_canonical(x->x()); return;
74 case Bytecodes::_ixor: set_constant(0); return;
75 case Bytecodes::_lxor: set_constant(jlong_cast(0)); return;
76 }
77 }
78
79 if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
80 // do constant folding for selected operations
81 switch (x->type()->tag()) {
82 case intTag:
83 { jint a = x->x()->type()->as_IntConstant()->value();
84 jint b = x->y()->type()->as_IntConstant()->value();
85 switch (x->op()) {
86 case Bytecodes::_iadd: set_constant(a + b); return;
87 case Bytecodes::_isub: set_constant(a - b); return;
88 case Bytecodes::_imul: set_constant(a * b); return;
89 case Bytecodes::_idiv:
90 if (b != 0) {
91 if (a == min_jint && b == -1) {
92 set_constant(min_jint);
93 } else {
94 set_constant(a / b);
95 }
96 return;
97 }
98 break;
99 case Bytecodes::_irem:
100 if (b != 0) {
101 if (a == min_jint && b == -1) {
102 set_constant(0);
103 } else {
104 set_constant(a % b);
105 }
106 return;
107 }
108 break;
109 case Bytecodes::_iand: set_constant(a & b); return;
110 case Bytecodes::_ior : set_constant(a | b); return;
111 case Bytecodes::_ixor: set_constant(a ^ b); return;
112 }
113 }
114 break;
115 case longTag:
116 { jlong a = x->x()->type()->as_LongConstant()->value();
117 jlong b = x->y()->type()->as_LongConstant()->value();
118 switch (x->op()) {
119 case Bytecodes::_ladd: set_constant(a + b); return;
120 case Bytecodes::_lsub: set_constant(a - b); return;
121 case Bytecodes::_lmul: set_constant(a * b); return;
122 case Bytecodes::_ldiv:
123 if (b != 0) {
124 set_constant(SharedRuntime::ldiv(b, a));
125 return;
126 }
127 break;
128 case Bytecodes::_lrem:
129 if (b != 0) {
130 set_constant(SharedRuntime::lrem(b, a));
131 return;
132 }
133 break;
134 case Bytecodes::_land: set_constant(a & b); return;
135 case Bytecodes::_lor : set_constant(a | b); return;
136 case Bytecodes::_lxor: set_constant(a ^ b); return;
137 }
138 }
139 break;
140 // other cases not implemented (must be extremely careful with floats & doubles!)
141 }
142 }
143 // make sure constant is on the right side, if any
144 move_const_to_right(x);
145
146 if (x->y()->type()->is_constant()) {
147 // do constant folding for selected operations
148 switch (x->type()->tag()) {
149 case intTag:
150 if (x->y()->type()->as_IntConstant()->value() == 0) {
151 switch (x->op()) {
152 case Bytecodes::_iadd: set_canonical(x->x()); return;
153 case Bytecodes::_isub: set_canonical(x->x()); return;
154 case Bytecodes::_imul: set_constant(0); return;
155 // Note: for div and rem, make sure that C semantics
156 // corresponds to Java semantics!
157 case Bytecodes::_iand: set_constant(0); return;
158 case Bytecodes::_ior : set_canonical(x->x()); return;
159 }
160 }
161 break;
162 case longTag:
163 if (x->y()->type()->as_LongConstant()->value() == (jlong)0) {
164 switch (x->op()) {
165 case Bytecodes::_ladd: set_canonical(x->x()); return;
166 case Bytecodes::_lsub: set_canonical(x->x()); return;
167 case Bytecodes::_lmul: set_constant((jlong)0); return;
168 // Note: for div and rem, make sure that C semantics
169 // corresponds to Java semantics!
170 case Bytecodes::_land: set_constant((jlong)0); return;
171 case Bytecodes::_lor : set_canonical(x->x()); return;
172 }
173 }
174 break;
175 }
176 }
177 }
178
179
180 void Canonicalizer::do_Phi (Phi* x) {}
181 void Canonicalizer::do_Constant (Constant* x) {}
182 void Canonicalizer::do_Local (Local* x) {}
183 void Canonicalizer::do_LoadField (LoadField* x) {}
184
185 // checks if v is in the block that is currently processed by
186 // GraphBuilder. This is the only block that has not BlockEnd yet.
187 static bool in_current_block(Value v) {
188 int max_distance = 4;
189 while (max_distance > 0 && v != NULL && v->as_BlockEnd() == NULL) {
190 v = v->next();
191 max_distance--;
192 }
193 return v == NULL;
194 }
195
196 void Canonicalizer::do_StoreField (StoreField* x) {
197 // If a value is going to be stored into a field or array some of
198 // the conversions emitted by javac are unneeded because the fields
199 // are packed to their natural size.
200 Convert* conv = x->value()->as_Convert();
201 if (conv) {
202 Value value = NULL;
203 BasicType type = x->field()->type()->basic_type();
204 switch (conv->op()) {
205 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
206 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
207 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
208 }
209 // limit this optimization to current block
210 if (value != NULL && in_current_block(conv)) {
211 set_canonical(new StoreField(x->obj(), x->offset(), x->field(), value, x->is_static(),
212 x->state_before(), x->needs_patching()));
213 return;
214 }
215 }
216
217 }
218
219 void Canonicalizer::do_ArrayLength (ArrayLength* x) {
220 NewArray* array = x->array()->as_NewArray();
221 if (array != NULL && array->length() != NULL) {
222 Constant* length = array->length()->as_Constant();
223 if (length != NULL) {
224 // do not use the Constant itself, but create a new Constant
225 // with same value Otherwise a Constant is live over multiple
226 // blocks without being registered in a state array.
227 assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
228 set_constant(length->type()->as_IntConstant()->value());
229 }
230 } else {
231 LoadField* lf = x->array()->as_LoadField();
232 if (lf != NULL) {
233 ciField* field = lf->field();
234 if (field->is_constant() && field->is_static()) {
235 // final static field
236 ciObject* c = field->constant_value().as_object();
237 if (c->is_array()) {
238 ciArray* array = (ciArray*) c;
239 set_constant(array->length());
240 }
241 }
242 }
243 }
244 }
245
246 void Canonicalizer::do_LoadIndexed (LoadIndexed* x) {}
247 void Canonicalizer::do_StoreIndexed (StoreIndexed* x) {
248 // If a value is going to be stored into a field or array some of
249 // the conversions emitted by javac are unneeded because the fields
250 // are packed to their natural size.
251 Convert* conv = x->value()->as_Convert();
252 if (conv) {
253 Value value = NULL;
254 BasicType type = x->elt_type();
255 switch (conv->op()) {
256 case Bytecodes::_i2b: if (type == T_BYTE) value = conv->value(); break;
257 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) value = conv->value(); break;
258 case Bytecodes::_i2c: if (type == T_CHAR || type == T_BYTE) value = conv->value(); break;
259 }
260 // limit this optimization to current block
261 if (value != NULL && in_current_block(conv)) {
262 set_canonical(new StoreIndexed(x->array(), x->index(), x->length(),
263 x->elt_type(), value, x->state_before()));
264 return;
265 }
266 }
267
268
269 }
270
271
272 void Canonicalizer::do_NegateOp(NegateOp* x) {
273 ValueType* t = x->x()->type();
274 if (t->is_constant()) {
275 switch (t->tag()) {
276 case intTag : set_constant(-t->as_IntConstant ()->value()); return;
277 case longTag : set_constant(-t->as_LongConstant ()->value()); return;
278 case floatTag : set_constant(-t->as_FloatConstant ()->value()); return;
279 case doubleTag: set_constant(-t->as_DoubleConstant()->value()); return;
280 default : ShouldNotReachHere();
281 }
282 }
283 }
284
285
286 void Canonicalizer::do_ArithmeticOp (ArithmeticOp* x) { do_Op2(x); }
287
288
289 void Canonicalizer::do_ShiftOp (ShiftOp* x) {
290 ValueType* t = x->x()->type();
291 ValueType* t2 = x->y()->type();
292 if (t->is_constant()) {
293 switch (t->tag()) {
294 case intTag : if (t->as_IntConstant()->value() == 0) { set_constant(0); return; } break;
295 case longTag : if (t->as_LongConstant()->value() == (jlong)0) { set_constant(jlong_cast(0)); return; } break;
296 default : ShouldNotReachHere();
297 }
298 if (t2->is_constant()) {
299 if (t->tag() == intTag) {
300 int value = t->as_IntConstant()->value();
301 int shift = t2->as_IntConstant()->value() & 31;
302 jint mask = ~(~0 << (32 - shift));
303 if (shift == 0) mask = ~0;
304 switch (x->op()) {
305 case Bytecodes::_ishl: set_constant(value << shift); return;
306 case Bytecodes::_ishr: set_constant(value >> shift); return;
307 case Bytecodes::_iushr: set_constant((value >> shift) & mask); return;
308 }
309 } else if (t->tag() == longTag) {
310 jlong value = t->as_LongConstant()->value();
311 int shift = t2->as_IntConstant()->value() & 63;
312 jlong mask = ~(~jlong_cast(0) << (64 - shift));
313 if (shift == 0) mask = ~jlong_cast(0);
314 switch (x->op()) {
315 case Bytecodes::_lshl: set_constant(value << shift); return;
316 case Bytecodes::_lshr: set_constant(value >> shift); return;
317 case Bytecodes::_lushr: set_constant((value >> shift) & mask); return;
318 }
319 }
320 }
321 }
322 if (t2->is_constant()) {
323 switch (t2->tag()) {
324 case intTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
325 case longTag : if (t2->as_IntConstant()->value() == 0) set_canonical(x->x()); return;
326 default : ShouldNotReachHere();
327 }
328 }
329 }
330
331
332 void Canonicalizer::do_LogicOp (LogicOp* x) { do_Op2(x); }
333 void Canonicalizer::do_CompareOp (CompareOp* x) {
334 if (x->x() == x->y()) {
335 switch (x->x()->type()->tag()) {
336 case longTag: set_constant(0); break;
337 case floatTag: {
338 FloatConstant* fc = x->x()->type()->as_FloatConstant();
339 if (fc) {
340 if (g_isnan(fc->value())) {
341 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
342 } else {
343 set_constant(0);
344 }
345 }
346 break;
347 }
348 case doubleTag: {
349 DoubleConstant* dc = x->x()->type()->as_DoubleConstant();
350 if (dc) {
351 if (g_isnan(dc->value())) {
352 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
353 } else {
354 set_constant(0);
355 }
356 }
357 break;
358 }
359 }
360 } else if (x->x()->type()->is_constant() && x->y()->type()->is_constant()) {
361 switch (x->x()->type()->tag()) {
362 case longTag: {
363 jlong vx = x->x()->type()->as_LongConstant()->value();
364 jlong vy = x->y()->type()->as_LongConstant()->value();
365 if (vx == vy)
366 set_constant(0);
367 else if (vx < vy)
368 set_constant(-1);
369 else
370 set_constant(1);
371 break;
372 }
373
374 case floatTag: {
375 float vx = x->x()->type()->as_FloatConstant()->value();
376 float vy = x->y()->type()->as_FloatConstant()->value();
377 if (g_isnan(vx) || g_isnan(vy))
378 set_constant(x->op() == Bytecodes::_fcmpl ? -1 : 1);
379 else if (vx == vy)
380 set_constant(0);
381 else if (vx < vy)
382 set_constant(-1);
383 else
384 set_constant(1);
385 break;
386 }
387
388 case doubleTag: {
389 double vx = x->x()->type()->as_DoubleConstant()->value();
390 double vy = x->y()->type()->as_DoubleConstant()->value();
391 if (g_isnan(vx) || g_isnan(vy))
392 set_constant(x->op() == Bytecodes::_dcmpl ? -1 : 1);
393 else if (vx == vy)
394 set_constant(0);
395 else if (vx < vy)
396 set_constant(-1);
397 else
398 set_constant(1);
399 break;
400 }
401 }
402
403 }
404 }
405
406
407 void Canonicalizer::do_IfInstanceOf(IfInstanceOf* x) {}
408
409 void Canonicalizer::do_IfOp(IfOp* x) {
410 // Caution: do not use do_Op2(x) here for now since
411 // we map the condition to the op for now!
412 move_const_to_right(x);
413 }
414
415
416 void Canonicalizer::do_Intrinsic (Intrinsic* x) {
417 switch (x->id()) {
418 case vmIntrinsics::_floatToRawIntBits : {
419 FloatConstant* c = x->argument_at(0)->type()->as_FloatConstant();
420 if (c != NULL) {
421 JavaValue v;
422 v.set_jfloat(c->value());
423 set_constant(v.get_jint());
424 }
425 break;
426 }
427 case vmIntrinsics::_intBitsToFloat : {
428 IntConstant* c = x->argument_at(0)->type()->as_IntConstant();
429 if (c != NULL) {
430 JavaValue v;
431 v.set_jint(c->value());
432 set_constant(v.get_jfloat());
433 }
434 break;
435 }
436 case vmIntrinsics::_doubleToRawLongBits : {
437 DoubleConstant* c = x->argument_at(0)->type()->as_DoubleConstant();
438 if (c != NULL) {
439 JavaValue v;
440 v.set_jdouble(c->value());
441 set_constant(v.get_jlong());
442 }
443 break;
444 }
445 case vmIntrinsics::_longBitsToDouble : {
446 LongConstant* c = x->argument_at(0)->type()->as_LongConstant();
447 if (c != NULL) {
448 JavaValue v;
449 v.set_jlong(c->value());
450 set_constant(v.get_jdouble());
451 }
452 break;
453 }
454 }
455 }
456
457 void Canonicalizer::do_Convert (Convert* x) {
458 if (x->value()->type()->is_constant()) {
459 switch (x->op()) {
460 case Bytecodes::_i2b: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 24) >> 24)); break;
461 case Bytecodes::_i2s: set_constant((int)((x->value()->type()->as_IntConstant()->value() << 16) >> 16)); break;
462 case Bytecodes::_i2c: set_constant((int)(x->value()->type()->as_IntConstant()->value() & ((1<<16)-1))); break;
463 case Bytecodes::_i2l: set_constant((jlong)(x->value()->type()->as_IntConstant()->value())); break;
464 case Bytecodes::_i2f: set_constant((float)(x->value()->type()->as_IntConstant()->value())); break;
465 case Bytecodes::_i2d: set_constant((double)(x->value()->type()->as_IntConstant()->value())); break;
466 case Bytecodes::_l2i: set_constant((int)(x->value()->type()->as_LongConstant()->value())); break;
467 case Bytecodes::_l2f: set_constant(SharedRuntime::l2f(x->value()->type()->as_LongConstant()->value())); break;
468 case Bytecodes::_l2d: set_constant(SharedRuntime::l2d(x->value()->type()->as_LongConstant()->value())); break;
469 case Bytecodes::_f2d: set_constant((double)(x->value()->type()->as_FloatConstant()->value())); break;
470 case Bytecodes::_f2i: set_constant(SharedRuntime::f2i(x->value()->type()->as_FloatConstant()->value())); break;
471 case Bytecodes::_f2l: set_constant(SharedRuntime::f2l(x->value()->type()->as_FloatConstant()->value())); break;
472 case Bytecodes::_d2f: set_constant((float)(x->value()->type()->as_DoubleConstant()->value())); break;
473 case Bytecodes::_d2i: set_constant(SharedRuntime::d2i(x->value()->type()->as_DoubleConstant()->value())); break;
474 case Bytecodes::_d2l: set_constant(SharedRuntime::d2l(x->value()->type()->as_DoubleConstant()->value())); break;
475 default:
476 ShouldNotReachHere();
477 }
478 }
479
480 Value value = x->value();
481 BasicType type = T_ILLEGAL;
482 LoadField* lf = value->as_LoadField();
483 if (lf) {
484 type = lf->field_type();
485 } else {
486 LoadIndexed* li = value->as_LoadIndexed();
487 if (li) {
488 type = li->elt_type();
489 } else {
490 Convert* conv = value->as_Convert();
491 if (conv) {
492 switch (conv->op()) {
493 case Bytecodes::_i2b: type = T_BYTE; break;
494 case Bytecodes::_i2s: type = T_SHORT; break;
495 case Bytecodes::_i2c: type = T_CHAR; break;
496 }
497 }
498 }
499 }
500 if (type != T_ILLEGAL) {
501 switch (x->op()) {
502 case Bytecodes::_i2b: if (type == T_BYTE) set_canonical(x->value()); break;
503 case Bytecodes::_i2s: if (type == T_SHORT || type == T_BYTE) set_canonical(x->value()); break;
504 case Bytecodes::_i2c: if (type == T_CHAR) set_canonical(x->value()); break;
505 }
506 } else {
507 Op2* op2 = x->value()->as_Op2();
508 if (op2 && op2->op() == Bytecodes::_iand && op2->y()->type()->is_constant()) {
509 jint safebits = 0;
510 jint mask = op2->y()->type()->as_IntConstant()->value();
511 switch (x->op()) {
512 case Bytecodes::_i2b: safebits = 0x7f; break;
513 case Bytecodes::_i2s: safebits = 0x7fff; break;
514 case Bytecodes::_i2c: safebits = 0xffff; break;
515 }
516 // When casting a masked integer to a smaller signed type, if
517 // the mask doesn't include the sign bit the cast isn't needed.
518 if (safebits && (mask & ~safebits) == 0) {
519 set_canonical(x->value());
520 }
521 }
522 }
523
524 }
525
526 void Canonicalizer::do_NullCheck (NullCheck* x) {
527 if (x->obj()->as_NewArray() != NULL || x->obj()->as_NewInstance() != NULL) {
528 set_canonical(x->obj());
529 } else {
530 Constant* con = x->obj()->as_Constant();
531 if (con) {
532 ObjectType* c = con->type()->as_ObjectType();
533 if (c && c->is_loaded()) {
534 ObjectConstant* oc = c->as_ObjectConstant();
535 if (!oc || !oc->value()->is_null_object()) {
536 set_canonical(con);
537 }
538 }
539 }
540 }
541 }
542
543 void Canonicalizer::do_Invoke (Invoke* x) {}
544 void Canonicalizer::do_NewInstance (NewInstance* x) {}
545 void Canonicalizer::do_NewTypeArray (NewTypeArray* x) {}
546 void Canonicalizer::do_NewObjectArray (NewObjectArray* x) {}
547 void Canonicalizer::do_NewMultiArray (NewMultiArray* x) {}
548 void Canonicalizer::do_CheckCast (CheckCast* x) {
549 if (x->klass()->is_loaded()) {
550 Value obj = x->obj();
551 ciType* klass = obj->exact_type();
552 if (klass == NULL) klass = obj->declared_type();
553 if (klass != NULL && klass->is_loaded() && klass->is_subtype_of(x->klass())) {
554 set_canonical(obj);
555 return;
556 }
557 // checkcast of null returns null
558 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
559 set_canonical(obj);
560 }
561 }
562 }
563 void Canonicalizer::do_InstanceOf (InstanceOf* x) {
564 if (x->klass()->is_loaded()) {
565 Value obj = x->obj();
566 ciType* exact = obj->exact_type();
567 if (exact != NULL && exact->is_loaded() && (obj->as_NewInstance() || obj->as_NewArray())) {
568 set_constant(exact->is_subtype_of(x->klass()) ? 1 : 0);
569 return;
570 }
571 // instanceof null returns false
572 if (obj->as_Constant() && obj->type()->as_ObjectType()->constant_value()->is_null_object()) {
573 set_constant(0);
574 }
575 }
576
577 }
578 void Canonicalizer::do_MonitorEnter (MonitorEnter* x) {}
579 void Canonicalizer::do_MonitorExit (MonitorExit* x) {}
580 void Canonicalizer::do_BlockBegin (BlockBegin* x) {}
581 void Canonicalizer::do_Goto (Goto* x) {}
582
583
584 static bool is_true(jlong x, If::Condition cond, jlong y) {
585 switch (cond) {
586 case If::eql: return x == y;
587 case If::neq: return x != y;
588 case If::lss: return x < y;
589 case If::leq: return x <= y;
590 case If::gtr: return x > y;
591 case If::geq: return x >= y;
592 }
593 ShouldNotReachHere();
594 return false;
595 }
596
597
598 void Canonicalizer::do_If(If* x) {
599 // move const to right
600 if (x->x()->type()->is_constant()) x->swap_operands();
601 // simplify
602 const Value l = x->x(); ValueType* lt = l->type();
603 const Value r = x->y(); ValueType* rt = r->type();
604
605 if (l == r && !lt->is_float_kind()) {
606 // pattern: If (a cond a) => simplify to Goto
607 BlockBegin* sux;
608 switch (x->cond()) {
609 case If::eql: sux = x->sux_for(true); break;
610 case If::neq: sux = x->sux_for(false); break;
611 case If::lss: sux = x->sux_for(false); break;
612 case If::leq: sux = x->sux_for(true); break;
613 case If::gtr: sux = x->sux_for(false); break;
614 case If::geq: sux = x->sux_for(true); break;
615 }
616 // If is a safepoint then the debug information should come from the state_before of the If.
617 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
618 return;
619 }
620
621 if (lt->is_constant() && rt->is_constant()) {
622 if (x->x()->as_Constant() != NULL) {
623 // pattern: If (lc cond rc) => simplify to: Goto
624 BlockBegin* sux = x->x()->as_Constant()->compare(x->cond(), x->y(),
625 x->sux_for(true),
626 x->sux_for(false));
627 if (sux != NULL) {
628 // If is a safepoint then the debug information should come from the state_before of the If.
629 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
630 }
631 }
632 } else if (rt->as_IntConstant() != NULL) {
633 // pattern: If (l cond rc) => investigate further
634 const jint rc = rt->as_IntConstant()->value();
635 if (l->as_CompareOp() != NULL) {
636 // pattern: If ((a cmp b) cond rc) => simplify to: If (x cond y) or: Goto
637 CompareOp* cmp = l->as_CompareOp();
638 bool unordered_is_less = cmp->op() == Bytecodes::_fcmpl || cmp->op() == Bytecodes::_dcmpl;
639 BlockBegin* lss_sux = x->sux_for(is_true(-1, x->cond(), rc)); // successor for a < b
640 BlockBegin* eql_sux = x->sux_for(is_true( 0, x->cond(), rc)); // successor for a = b
641 BlockBegin* gtr_sux = x->sux_for(is_true(+1, x->cond(), rc)); // successor for a > b
642 BlockBegin* nan_sux = unordered_is_less ? lss_sux : gtr_sux ; // successor for unordered
643 // Note: At this point all successors (lss_sux, eql_sux, gtr_sux, nan_sux) are
644 // equal to x->tsux() or x->fsux(). Furthermore, nan_sux equals either
645 // lss_sux or gtr_sux.
646 if (lss_sux == eql_sux && eql_sux == gtr_sux) {
647 // all successors identical => simplify to: Goto
648 set_canonical(new Goto(lss_sux, x->state_before(), x->is_safepoint()));
649 } else {
650 // two successors differ and two successors are the same => simplify to: If (x cmp y)
651 // determine new condition & successors
652 If::Condition cond;
653 BlockBegin* tsux = NULL;
654 BlockBegin* fsux = NULL;
655 if (lss_sux == eql_sux) { cond = If::leq; tsux = lss_sux; fsux = gtr_sux; }
656 else if (lss_sux == gtr_sux) { cond = If::neq; tsux = lss_sux; fsux = eql_sux; }
657 else if (eql_sux == gtr_sux) { cond = If::geq; tsux = eql_sux; fsux = lss_sux; }
658 else { ShouldNotReachHere(); }
659 If* canon = new If(cmp->x(), cond, nan_sux == tsux, cmp->y(), tsux, fsux, cmp->state_before(), x->is_safepoint());
660 if (cmp->x() == cmp->y()) {
661 do_If(canon);
662 } else {
663 if (compilation()->profile_branches()) {
664 // TODO: If profiling, leave floating point comparisons unoptimized.
665 // We currently do not support profiling of the unordered case.
666 switch(cmp->op()) {
667 case Bytecodes::_fcmpl: case Bytecodes::_fcmpg:
668 case Bytecodes::_dcmpl: case Bytecodes::_dcmpg:
669 set_canonical(x);
670 return;
671 }
672 }
673 set_canonical(canon);
674 set_bci(cmp->state_before()->bci());
675 }
676 }
677 } else if (l->as_InstanceOf() != NULL) {
678 // NOTE: Code permanently disabled for now since it leaves the old InstanceOf
679 // instruction in the graph (it is pinned). Need to fix this at some point.
680 // It should also be left in the graph when generating a profiled method version or Goto
681 // has to know that it was an InstanceOf.
682 return;
683 // pattern: If ((obj instanceof klass) cond rc) => simplify to: IfInstanceOf or: Goto
684 InstanceOf* inst = l->as_InstanceOf();
685 BlockBegin* is_inst_sux = x->sux_for(is_true(1, x->cond(), rc)); // successor for instanceof == 1
686 BlockBegin* no_inst_sux = x->sux_for(is_true(0, x->cond(), rc)); // successor for instanceof == 0
687 if (is_inst_sux == no_inst_sux && inst->is_loaded()) {
688 // both successors identical and klass is loaded => simplify to: Goto
689 set_canonical(new Goto(is_inst_sux, x->state_before(), x->is_safepoint()));
690 } else {
691 // successors differ => simplify to: IfInstanceOf
692 set_canonical(new IfInstanceOf(inst->klass(), inst->obj(), true, inst->state_before()->bci(), is_inst_sux, no_inst_sux));
693 }
694 }
695 } else if (rt == objectNull && (l->as_NewInstance() || l->as_NewArray())) {
696 if (x->cond() == Instruction::eql) {
697 set_canonical(new Goto(x->fsux(), x->state_before(), x->is_safepoint()));
698 } else {
699 assert(x->cond() == Instruction::neq, "only other valid case");
700 set_canonical(new Goto(x->tsux(), x->state_before(), x->is_safepoint()));
701 }
702 }
703 }
704
705
706 void Canonicalizer::do_TableSwitch(TableSwitch* x) {
707 if (x->tag()->type()->is_constant()) {
708 int v = x->tag()->type()->as_IntConstant()->value();
709 BlockBegin* sux = x->default_sux();
710 if (v >= x->lo_key() && v <= x->hi_key()) {
711 sux = x->sux_at(v - x->lo_key());
712 }
713 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
714 } else if (x->number_of_sux() == 1) {
715 // NOTE: Code permanently disabled for now since the switch statement's
716 // tag expression may produce side-effects in which case it must
717 // be executed.
718 return;
719 // simplify to Goto
720 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
721 } else if (x->number_of_sux() == 2) {
722 // NOTE: Code permanently disabled for now since it produces two new nodes
723 // (Constant & If) and the Canonicalizer cannot return them correctly
724 // yet. For now we copied the corresponding code directly into the
725 // GraphBuilder (i.e., we should never reach here).
726 return;
727 // simplify to If
728 assert(x->lo_key() == x->hi_key(), "keys must be the same");
729 Constant* key = new Constant(new IntConstant(x->lo_key()));
730 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
731 }
732 }
733
734
735 void Canonicalizer::do_LookupSwitch(LookupSwitch* x) {
736 if (x->tag()->type()->is_constant()) {
737 int v = x->tag()->type()->as_IntConstant()->value();
738 BlockBegin* sux = x->default_sux();
739 for (int i = 0; i < x->length(); i++) {
740 if (v == x->key_at(i)) {
741 sux = x->sux_at(i);
742 }
743 }
744 set_canonical(new Goto(sux, x->state_before(), x->is_safepoint()));
745 } else if (x->number_of_sux() == 1) {
746 // NOTE: Code permanently disabled for now since the switch statement's
747 // tag expression may produce side-effects in which case it must
748 // be executed.
749 return;
750 // simplify to Goto
751 set_canonical(new Goto(x->default_sux(), x->state_before(), x->is_safepoint()));
752 } else if (x->number_of_sux() == 2) {
753 // NOTE: Code permanently disabled for now since it produces two new nodes
754 // (Constant & If) and the Canonicalizer cannot return them correctly
755 // yet. For now we copied the corresponding code directly into the
756 // GraphBuilder (i.e., we should never reach here).
757 return;
758 // simplify to If
759 assert(x->length() == 1, "length must be the same");
760 Constant* key = new Constant(new IntConstant(x->key_at(0)));
761 set_canonical(new If(x->tag(), If::eql, true, key, x->sux_at(0), x->default_sux(), x->state_before(), x->is_safepoint()));
762 }
763 }
764
765
766 void Canonicalizer::do_Return (Return* x) {}
767 void Canonicalizer::do_Throw (Throw* x) {}
768 void Canonicalizer::do_Base (Base* x) {}
769 void Canonicalizer::do_OsrEntry (OsrEntry* x) {}
770 void Canonicalizer::do_ExceptionObject(ExceptionObject* x) {}
771
772 static bool match_index_and_scale(Instruction* instr,
773 Instruction** index,
774 int* log2_scale,
775 Instruction** instr_to_unpin) {
776 *instr_to_unpin = NULL;
777
778 // Skip conversion ops
779 Convert* convert = instr->as_Convert();
780 if (convert != NULL) {
781 instr = convert->value();
782 }
783
784 ShiftOp* shift = instr->as_ShiftOp();
785 if (shift != NULL) {
786 if (shift->is_pinned()) {
787 *instr_to_unpin = shift;
788 }
789 // Constant shift value?
790 Constant* con = shift->y()->as_Constant();
791 if (con == NULL) return false;
792 // Well-known type and value?
793 IntConstant* val = con->type()->as_IntConstant();
794 if (val == NULL) return false;
795 if (shift->x()->type() != intType) return false;
796 *index = shift->x();
797 int tmp_scale = val->value();
798 if (tmp_scale >= 0 && tmp_scale < 4) {
799 *log2_scale = tmp_scale;
800 return true;
801 } else {
802 return false;
803 }
804 }
805
806 ArithmeticOp* arith = instr->as_ArithmeticOp();
807 if (arith != NULL) {
808 if (arith->is_pinned()) {
809 *instr_to_unpin = arith;
810 }
811 // Check for integer multiply
812 if (arith->op() == Bytecodes::_imul) {
813 // See if either arg is a known constant
814 Constant* con = arith->x()->as_Constant();
815 if (con != NULL) {
816 *index = arith->y();
817 } else {
818 con = arith->y()->as_Constant();
819 if (con == NULL) return false;
820 *index = arith->x();
821 }
822 if ((*index)->type() != intType) return false;
823 // Well-known type and value?
824 IntConstant* val = con->type()->as_IntConstant();
825 if (val == NULL) return false;
826 switch (val->value()) {
827 case 1: *log2_scale = 0; return true;
828 case 2: *log2_scale = 1; return true;
829 case 4: *log2_scale = 2; return true;
830 case 8: *log2_scale = 3; return true;
831 default: return false;
832 }
833 }
834 }
835
836 // Unknown instruction sequence; don't touch it
837 return false;
838 }
839
840
841 static bool match(UnsafeRawOp* x,
842 Instruction** base,
843 Instruction** index,
844 int* log2_scale) {
845 Instruction* instr_to_unpin = NULL;
846 ArithmeticOp* root = x->base()->as_ArithmeticOp();
847 if (root == NULL) return false;
848 // Limit ourselves to addition for now
849 if (root->op() != Bytecodes::_ladd) return false;
850 // Try to find shift or scale op
851 if (match_index_and_scale(root->y(), index, log2_scale, &instr_to_unpin)) {
852 *base = root->x();
853 } else if (match_index_and_scale(root->x(), index, log2_scale, &instr_to_unpin)) {
854 *base = root->y();
855 } else if (root->y()->as_Convert() != NULL) {
856 Convert* convert = root->y()->as_Convert();
857 if (convert->op() == Bytecodes::_i2l && convert->value()->type() == intType) {
858 // pick base and index, setting scale at 1
859 *base = root->x();
860 *index = convert->value();
861 *log2_scale = 0;
862 } else {
863 return false;
864 }
865 } else {
866 // doesn't match any expected sequences
867 return false;
868 }
869
870 // If the value is pinned then it will be always be computed so
871 // there's no profit to reshaping the expression.
872 return !root->is_pinned();
873 }
874
875
876 void Canonicalizer::do_UnsafeRawOp(UnsafeRawOp* x) {
877 Instruction* base = NULL;
878 Instruction* index = NULL;
879 int log2_scale;
880
881 if (match(x, &base, &index, &log2_scale)) {
882 x->set_base(base);
883 x->set_index(index);
884 x->set_log2_scale(log2_scale);
885 if (PrintUnsafeOptimization) {
886 tty->print_cr("Canonicalizer: UnsafeRawOp id %d: base = id %d, index = id %d, log2_scale = %d",
887 x->id(), x->base()->id(), x->index()->id(), x->log2_scale());
888 }
889 }
890 }
891
892 void Canonicalizer::do_RoundFP(RoundFP* x) {}
893 void Canonicalizer::do_UnsafeGetRaw(UnsafeGetRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
894 void Canonicalizer::do_UnsafePutRaw(UnsafePutRaw* x) { if (OptimizeUnsafes) do_UnsafeRawOp(x); }
895 void Canonicalizer::do_UnsafeGetObject(UnsafeGetObject* x) {}
896 void Canonicalizer::do_UnsafePutObject(UnsafePutObject* x) {}
897 void Canonicalizer::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {}
898 void Canonicalizer::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
899 void Canonicalizer::do_ProfileCall(ProfileCall* x) {}
900 void Canonicalizer::do_ProfileInvoke(ProfileInvoke* x) {}
901 void Canonicalizer::do_RuntimeCall(RuntimeCall* x) {}