30 #include "opto/connode.hpp"
31 #include "opto/machnode.hpp"
32 #include "opto/mulnode.hpp"
33 #include "opto/phaseX.hpp"
34 #include "opto/subnode.hpp"
35
36 // Portions of code courtesy of Clifford Click
37
38 // Classic Add functionality. This covers all the usual 'add' behaviors for
39 // an algebraic ring. Add-integer, add-float, add-double, and binary-or are
40 // all inherited from this class. The various identity values are supplied
41 // by virtual functions.
42
43
44 //=============================================================================
45 //------------------------------hash-------------------------------------------
46 // Hash function over AddNodes. Needs to be commutative; i.e., I swap
47 // (commute) inputs to AddNodes willy-nilly so the hash function must return
48 // the same value in the presence of edge swapping.
49 uint AddNode::hash() const {
50 return (uintptr_t)in(1) + (uintptr_t)in(2) + Opcode();
51 }
52
53 //------------------------------Identity---------------------------------------
54 // If either input is a constant 0, return the other input.
55 Node* AddNode::Identity(PhaseGVN* phase) {
56 const Type *zero = add_id(); // The additive identity
57 if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
58 if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
59 return this;
60 }
61
62 //------------------------------commute----------------------------------------
63 // Commute operands to move loads and constants to the right.
64 static bool commute(Node *add, bool con_left, bool con_right) {
65 Node *in1 = add->in(1);
66 Node *in2 = add->in(2);
67
68 // Convert "1+x" into "x+1".
69 // Right is a constant; leave it
70 if( con_right ) return false;
106 }
107
108 //------------------------------Idealize---------------------------------------
109 // If we get here, we assume we are associative!
110 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
111 const Type *t1 = phase->type( in(1) );
112 const Type *t2 = phase->type( in(2) );
113 bool con_left = t1->singleton();
114 bool con_right = t2->singleton();
115
116 // Check for commutative operation desired
117 if( commute(this,con_left,con_right) ) return this;
118
119 AddNode *progress = NULL; // Progress flag
120
121 // Convert "(x+1)+2" into "x+(1+2)". If the right input is a
122 // constant, and the left input is an add of a constant, flatten the
123 // expression tree.
124 Node *add1 = in(1);
125 Node *add2 = in(2);
126 int add1_op = add1->Opcode();
127 int this_op = Opcode();
128 if( con_right && t2 != Type::TOP && // Right input is a constant?
129 add1_op == this_op ) { // Left input is an Add?
130
131 // Type of left _in right input
132 const Type *t12 = phase->type( add1->in(2) );
133 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
134 // Check for rare case of closed data cycle which can happen inside
135 // unreachable loops. In these cases the computation is undefined.
136 #ifdef ASSERT
137 Node *add11 = add1->in(1);
138 int add11_op = add11->Opcode();
139 if( (add1 == add1->in(1))
140 || (add11_op == this_op && add11->in(1) == add1) ) {
141 assert(false, "dead loop in AddNode::Ideal");
142 }
143 #endif
144 // The Add of the flattened expression
145 Node *x1 = add1->in(1);
146 Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));
147 PhaseIterGVN *igvn = phase->is_IterGVN();
148 if( igvn ) {
149 set_req_X(2,x2,igvn);
150 set_req_X(1,x1,igvn);
151 } else {
152 set_req(2,x2);
153 set_req(1,x1);
154 }
155 progress = this; // Made progress
156 add1 = in(1);
157 add1_op = add1->Opcode();
158 }
159 }
160
161 // Convert "(x+1)+y" into "(x+y)+1". Push constants down the expression tree.
162 if( add1_op == this_op && !con_right ) {
163 Node *a12 = add1->in(2);
164 const Type *t12 = phase->type( a12 );
165 if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
166 !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {
167 assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
168 add2 = add1->clone();
169 add2->set_req(2, in(2));
170 add2 = phase->transform(add2);
171 set_req(1, add2);
172 set_req(2, a12);
173 progress = this;
174 add2 = a12;
175 }
176 }
177
178 // Convert "x+(y+1)" into "(x+y)+1". Push constants down the expression tree.
179 int add2_op = add2->Opcode();
180 if( add2_op == this_op && !con_left ) {
181 Node *a22 = add2->in(2);
182 const Type *t22 = phase->type( a22 );
183 if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
184 !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {
185 assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
186 Node *addx = add2->clone();
187 addx->set_req(1, in(1));
188 addx->set_req(2, add2->in(1));
189 addx = phase->transform(addx);
190 set_req(1, addx);
191 set_req(2, a22);
192 progress = this;
193 PhaseIterGVN *igvn = phase->is_IterGVN();
194 if (add2->outcnt() == 0 && igvn) {
195 // add disconnected.
196 igvn->_worklist.push(add2);
197 }
198 }
199 }
223
224 return add_ring(t1,t2); // Local flavor of type addition
225 }
226
227 //------------------------------add_identity-----------------------------------
228 // Check for addition of the identity
229 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
230 const Type *zero = add_id(); // The additive identity
231 if( t1->higher_equal( zero ) ) return t2;
232 if( t2->higher_equal( zero ) ) return t1;
233
234 return NULL;
235 }
236
237
238 //=============================================================================
239 //------------------------------Idealize---------------------------------------
240 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {
241 Node* in1 = in(1);
242 Node* in2 = in(2);
243 int op1 = in1->Opcode();
244 int op2 = in2->Opcode();
245 // Fold (con1-x)+con2 into (con1+con2)-x
246 if ( op1 == Op_AddI && op2 == Op_SubI ) {
247 // Swap edges to try optimizations below
248 in1 = in2;
249 in2 = in(1);
250 op1 = op2;
251 op2 = in2->Opcode();
252 }
253 if( op1 == Op_SubI ) {
254 const Type *t_sub1 = phase->type( in1->in(1) );
255 const Type *t_2 = phase->type( in2 );
256 if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
257 return new SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ), in1->in(2) );
258 // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
259 if( op2 == Op_SubI ) {
260 // Check for dead cycle: d = (a-b)+(c-d)
261 assert( in1->in(2) != this && in2->in(2) != this,
262 "dead loop in AddINode::Ideal" );
263 Node *sub = new SubINode(NULL, NULL);
264 sub->init_req(1, phase->transform(new AddINode(in1->in(1), in2->in(1) ) ));
265 sub->init_req(2, phase->transform(new AddINode(in1->in(2), in2->in(2) ) ));
266 return sub;
267 }
268 // Convert "(a-b)+(b+c)" into "(a+c)"
269 if( op2 == Op_AddI && in1->in(2) == in2->in(1) ) {
270 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
271 return new AddINode(in1->in(1), in2->in(2));
272 }
273 // Convert "(a-b)+(c+b)" into "(a+c)"
274 if( op2 == Op_AddI && in1->in(2) == in2->in(2) ) {
275 assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
276 return new AddINode(in1->in(1), in2->in(1));
277 }
278 // Convert "(a-b)+(b-c)" into "(a-c)"
279 if( op2 == Op_SubI && in1->in(2) == in2->in(1) ) {
280 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
281 return new SubINode(in1->in(1), in2->in(2));
282 }
283 // Convert "(a-b)+(c-a)" into "(c-b)"
284 if( op2 == Op_SubI && in1->in(1) == in2->in(2) ) {
285 assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
286 return new SubINode(in2->in(1), in1->in(2));
287 }
288 }
289
290 // Convert "x+(0-y)" into "(x-y)"
291 if( op2 == Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )
292 return new SubINode(in1, in2->in(2) );
293
294 // Convert "(0-y)+x" into "(x-y)"
295 if( op1 == Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )
296 return new SubINode( in2, in1->in(2) );
297
298 // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
299 // Helps with array allocation math constant folding
300 // See 4790063:
301 // Unrestricted transformation is unsafe for some runtime values of 'x'
302 // ( x == 0, z == 1, y == -1 ) fails
303 // ( x == -5, z == 1, y == 1 ) fails
304 // Transform works for small z and small negative y when the addition
305 // (x + (y << z)) does not cross zero.
306 // Implement support for negative y and (x >= -(y << z))
307 // Have not observed cases where type information exists to support
308 // positive y and (x <= -(y << z))
309 if( op1 == Op_URShiftI && op2 == Op_ConI &&
310 in1->in(2)->Opcode() == Op_ConI ) {
311 jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
312 jint y = phase->type( in2 )->is_int()->get_con();
313
314 if( z < 5 && -5 < y && y < 0 ) {
315 const Type *t_in11 = phase->type(in1->in(1));
316 if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {
317 Node *a = phase->transform( new AddINode( in1->in(1), phase->intcon(y<<z) ) );
318 return new URShiftINode( a, in1->in(2) );
319 }
320 }
321 }
322
323 return AddNode::Ideal(phase, can_reshape);
324 }
325
326
327 //------------------------------Identity---------------------------------------
328 // Fold (x-y)+y OR y+(x-y) into x
329 Node* AddINode::Identity(PhaseGVN* phase) {
330 if( in(1)->Opcode() == Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {
331 return in(1)->in(1);
332 }
333 else if( in(2)->Opcode() == Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {
334 return in(2)->in(1);
335 }
336 return AddNode::Identity(phase);
337 }
338
339
340 //------------------------------add_ring---------------------------------------
341 // Supplied function returns the sum of the inputs. Guaranteed never
342 // to be passed a TOP or BOTTOM type, these are filtered out by
343 // pre-check.
344 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
345 const TypeInt *r0 = t0->is_int(); // Handy access
346 const TypeInt *r1 = t1->is_int();
347 int lo = java_add(r0->_lo, r1->_lo);
348 int hi = java_add(r0->_hi, r1->_hi);
349 if( !(r0->is_con() && r1->is_con()) ) {
350 // Not both constants, compute approximate result
351 if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
352 lo = min_jint; hi = max_jint; // Underflow on the low side
353 }
354 if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
355 lo = min_jint; hi = max_jint; // Overflow on the high side
356 }
357 if( lo > hi ) { // Handle overflow
358 lo = min_jint; hi = max_jint;
359 }
360 } else {
361 // both constants, compute precise result using 'lo' and 'hi'
362 // Semantics define overflow and underflow for integer addition
363 // as expected. In particular: 0x80000000 + 0x80000000 --> 0x0
364 }
365 return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
366 }
367
368
369 //=============================================================================
370 //------------------------------Idealize---------------------------------------
371 Node *AddLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
372 Node* in1 = in(1);
373 Node* in2 = in(2);
374 int op1 = in1->Opcode();
375 int op2 = in2->Opcode();
376 // Fold (con1-x)+con2 into (con1+con2)-x
377 if ( op1 == Op_AddL && op2 == Op_SubL ) {
378 // Swap edges to try optimizations below
379 in1 = in2;
380 in2 = in(1);
381 op1 = op2;
382 op2 = in2->Opcode();
383 }
384 // Fold (con1-x)+con2 into (con1+con2)-x
385 if( op1 == Op_SubL ) {
386 const Type *t_sub1 = phase->type( in1->in(1) );
387 const Type *t_2 = phase->type( in2 );
388 if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
389 return new SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ), in1->in(2) );
390 // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
391 if( op2 == Op_SubL ) {
392 // Check for dead cycle: d = (a-b)+(c-d)
393 assert( in1->in(2) != this && in2->in(2) != this,
394 "dead loop in AddLNode::Ideal" );
395 Node *sub = new SubLNode(NULL, NULL);
396 sub->init_req(1, phase->transform(new AddLNode(in1->in(1), in2->in(1) ) ));
397 sub->init_req(2, phase->transform(new AddLNode(in1->in(2), in2->in(2) ) ));
398 return sub;
399 }
400 // Convert "(a-b)+(b+c)" into "(a+c)"
401 if( op2 == Op_AddL && in1->in(2) == in2->in(1) ) {
402 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
403 return new AddLNode(in1->in(1), in2->in(2));
404 }
405 // Convert "(a-b)+(c+b)" into "(a+c)"
406 if( op2 == Op_AddL && in1->in(2) == in2->in(2) ) {
407 assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
408 return new AddLNode(in1->in(1), in2->in(1));
409 }
410 // Convert "(a-b)+(b-c)" into "(a-c)"
411 if( op2 == Op_SubL && in1->in(2) == in2->in(1) ) {
412 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
413 return new SubLNode(in1->in(1), in2->in(2));
414 }
415 // Convert "(a-b)+(c-a)" into "(c-b)"
416 if( op2 == Op_SubL && in1->in(1) == in1->in(2) ) {
417 assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
418 return new SubLNode(in2->in(1), in1->in(2));
419 }
420 }
421
422 // Convert "x+(0-y)" into "(x-y)"
423 if( op2 == Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )
424 return new SubLNode( in1, in2->in(2) );
425
426 // Convert "(0-y)+x" into "(x-y)"
427 if( op1 == Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )
428 return new SubLNode( in2, in1->in(2) );
429
430 // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"
431 // into "(X<<1)+Y" and let shift-folding happen.
432 if( op2 == Op_AddL &&
433 in2->in(1) == in1 &&
434 op1 != Op_ConL &&
435 0 ) {
436 Node *shift = phase->transform(new LShiftLNode(in1,phase->intcon(1)));
437 return new AddLNode(shift,in2->in(2));
438 }
439
440 return AddNode::Ideal(phase, can_reshape);
441 }
442
443
444 //------------------------------Identity---------------------------------------
445 // Fold (x-y)+y OR y+(x-y) into x
446 Node* AddLNode::Identity(PhaseGVN* phase) {
447 if( in(1)->Opcode() == Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {
448 return in(1)->in(1);
449 }
450 else if( in(2)->Opcode() == Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {
451 return in(2)->in(1);
452 }
453 return AddNode::Identity(phase);
454 }
455
456
457 //------------------------------add_ring---------------------------------------
458 // Supplied function returns the sum of the inputs. Guaranteed never
459 // to be passed a TOP or BOTTOM type, these are filtered out by
460 // pre-check.
461 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
462 const TypeLong *r0 = t0->is_long(); // Handy access
463 const TypeLong *r1 = t1->is_long();
464 jlong lo = java_add(r0->_lo, r1->_lo);
465 jlong hi = java_add(r0->_hi, r1->_hi);
466 if( !(r0->is_con() && r1->is_con()) ) {
467 // Not both constants, compute approximate result
468 if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
469 lo =min_jlong; hi = max_jlong; // Underflow on the low side
470 }
606 set_req(Offset,offset);
607 }
608 return this;
609 }
610 }
611
612 // Raw pointers?
613 if( in(Base)->bottom_type() == Type::TOP ) {
614 // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.
615 if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
616 Node* offset = in(Offset);
617 return new CastX2PNode(offset);
618 }
619 }
620
621 // If the right is an add of a constant, push the offset down.
622 // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
623 // The idea is to merge array_base+scaled_index groups together,
624 // and only have different constant offsets from the same base.
625 const Node *add = in(Offset);
626 if( add->Opcode() == Op_AddX && add->in(1) != add ) {
627 const Type *t22 = phase->type( add->in(2) );
628 if( t22->singleton() && (t22 != Type::TOP) ) { // Right input is an add of a constant?
629 set_req(Address, phase->transform(new AddPNode(in(Base),in(Address),add->in(1))));
630 set_req(Offset, add->in(2));
631 PhaseIterGVN *igvn = phase->is_IterGVN();
632 if (add->outcnt() == 0 && igvn) {
633 // add disconnected.
634 igvn->_worklist.push((Node*)add);
635 }
636 return this; // Made progress
637 }
638 }
639
640 return NULL; // No progress
641 }
642
643 //------------------------------bottom_type------------------------------------
644 // Bottom-type is the pointer-type with unknown offset.
645 const Type *AddPNode::bottom_type() const {
646 if (in(Address) == NULL) return TypePtr::BOTTOM;
647 const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
648 if( !tp ) return Type::TOP; // TOP input means TOP output
649 assert( in(Offset)->Opcode() != Op_ConP, "" );
650 const Type *t = in(Offset)->bottom_type();
651 if( t == Type::TOP )
652 return tp->add_offset(Type::OffsetTop);
653 const TypeX *tx = t->is_intptr_t();
654 intptr_t txoffset = Type::OffsetBot;
655 if (tx->is_con()) { // Left input is an add of a constant?
656 txoffset = tx->get_con();
657 }
658 return tp->add_offset(txoffset);
659 }
660
661 //------------------------------Value------------------------------------------
662 const Type* AddPNode::Value(PhaseGVN* phase) const {
663 // Either input is TOP ==> the result is TOP
664 const Type *t1 = phase->type( in(Address) );
665 const Type *t2 = phase->type( in(Offset) );
666 if( t1 == Type::TOP ) return Type::TOP;
667 if( t2 == Type::TOP ) return Type::TOP;
668
669 // Left input is a pointer
837 // Supplied function returns the sum of the inputs.
838 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
839 const TypeInt *r0 = t0->is_int(); // Handy access
840 const TypeInt *r1 = t1->is_int();
841
842 // Otherwise just MAX them bits.
843 return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
844 }
845
846 //=============================================================================
847 //------------------------------Idealize---------------------------------------
848 // MINs show up in range-check loop limit calculations. Look for
849 // "MIN2(x+c0,MIN2(y,x+c1))". Pick the smaller constant: "MIN2(x+c0,y)"
850 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
851 Node *progress = NULL;
852 // Force a right-spline graph
853 Node *l = in(1);
854 Node *r = in(2);
855 // Transform MinI1( MinI2(a,b), c) into MinI1( a, MinI2(b,c) )
856 // to force a right-spline graph for the rest of MinINode::Ideal().
857 if( l->Opcode() == Op_MinI ) {
858 assert( l != l->in(1), "dead loop in MinINode::Ideal" );
859 r = phase->transform(new MinINode(l->in(2),r));
860 l = l->in(1);
861 set_req(1, l);
862 set_req(2, r);
863 return this;
864 }
865
866 // Get left input & constant
867 Node *x = l;
868 int x_off = 0;
869 if( x->Opcode() == Op_AddI && // Check for "x+c0" and collect constant
870 x->in(2)->is_Con() ) {
871 const Type *t = x->in(2)->bottom_type();
872 if( t == Type::TOP ) return NULL; // No progress
873 x_off = t->is_int()->get_con();
874 x = x->in(1);
875 }
876
877 // Scan a right-spline-tree for MINs
878 Node *y = r;
879 int y_off = 0;
880 // Check final part of MIN tree
881 if( y->Opcode() == Op_AddI && // Check for "y+c1" and collect constant
882 y->in(2)->is_Con() ) {
883 const Type *t = y->in(2)->bottom_type();
884 if( t == Type::TOP ) return NULL; // No progress
885 y_off = t->is_int()->get_con();
886 y = y->in(1);
887 }
888 if( x->_idx > y->_idx && r->Opcode() != Op_MinI ) {
889 swap_edges(1, 2);
890 return this;
891 }
892
893
894 if( r->Opcode() == Op_MinI ) {
895 assert( r != r->in(2), "dead loop in MinINode::Ideal" );
896 y = r->in(1);
897 // Check final part of MIN tree
898 if( y->Opcode() == Op_AddI &&// Check for "y+c1" and collect constant
899 y->in(2)->is_Con() ) {
900 const Type *t = y->in(2)->bottom_type();
901 if( t == Type::TOP ) return NULL; // No progress
902 y_off = t->is_int()->get_con();
903 y = y->in(1);
904 }
905
906 if( x->_idx > y->_idx )
907 return new MinINode(r->in(1),phase->transform(new MinINode(l,r->in(2))));
908
909 // See if covers: MIN2(x+c0,MIN2(y+c1,z))
910 if( !phase->eqv(x,y) ) return NULL;
911 // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into
912 // MIN2(x+c0 or x+c1 which less, z).
913 return new MinINode(phase->transform(new AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));
914 } else {
915 // See if covers: MIN2(x+c0,y+c1)
916 if( !phase->eqv(x,y) ) return NULL;
917 // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.
918 return new AddINode(x,phase->intcon(MIN2(x_off,y_off)));
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30 #include "opto/connode.hpp"
31 #include "opto/machnode.hpp"
32 #include "opto/mulnode.hpp"
33 #include "opto/phaseX.hpp"
34 #include "opto/subnode.hpp"
35
36 // Portions of code courtesy of Clifford Click
37
38 // Classic Add functionality. This covers all the usual 'add' behaviors for
39 // an algebraic ring. Add-integer, add-float, add-double, and binary-or are
40 // all inherited from this class. The various identity values are supplied
41 // by virtual functions.
42
43
44 //=============================================================================
45 //------------------------------hash-------------------------------------------
46 // Hash function over AddNodes. Needs to be commutative; i.e., I swap
47 // (commute) inputs to AddNodes willy-nilly so the hash function must return
48 // the same value in the presence of edge swapping.
49 uint AddNode::hash() const {
50 return (uintptr_t)in(1) + (uintptr_t)in(2) + static_cast<uint>(Opcode());
51 }
52
53 //------------------------------Identity---------------------------------------
54 // If either input is a constant 0, return the other input.
55 Node* AddNode::Identity(PhaseGVN* phase) {
56 const Type *zero = add_id(); // The additive identity
57 if( phase->type( in(1) )->higher_equal( zero ) ) return in(2);
58 if( phase->type( in(2) )->higher_equal( zero ) ) return in(1);
59 return this;
60 }
61
62 //------------------------------commute----------------------------------------
63 // Commute operands to move loads and constants to the right.
64 static bool commute(Node *add, bool con_left, bool con_right) {
65 Node *in1 = add->in(1);
66 Node *in2 = add->in(2);
67
68 // Convert "1+x" into "x+1".
69 // Right is a constant; leave it
70 if( con_right ) return false;
106 }
107
108 //------------------------------Idealize---------------------------------------
109 // If we get here, we assume we are associative!
110 Node *AddNode::Ideal(PhaseGVN *phase, bool can_reshape) {
111 const Type *t1 = phase->type( in(1) );
112 const Type *t2 = phase->type( in(2) );
113 bool con_left = t1->singleton();
114 bool con_right = t2->singleton();
115
116 // Check for commutative operation desired
117 if( commute(this,con_left,con_right) ) return this;
118
119 AddNode *progress = NULL; // Progress flag
120
121 // Convert "(x+1)+2" into "x+(1+2)". If the right input is a
122 // constant, and the left input is an add of a constant, flatten the
123 // expression tree.
124 Node *add1 = in(1);
125 Node *add2 = in(2);
126 Opcodes add1_op = add1->Opcode();
127 Opcodes this_op = Opcode();
128 if( con_right && t2 != Type::TOP && // Right input is a constant?
129 add1_op == this_op ) { // Left input is an Add?
130
131 // Type of left _in right input
132 const Type *t12 = phase->type( add1->in(2) );
133 if( t12->singleton() && t12 != Type::TOP ) { // Left input is an add of a constant?
134 // Check for rare case of closed data cycle which can happen inside
135 // unreachable loops. In these cases the computation is undefined.
136 #ifdef ASSERT
137 Node *add11 = add1->in(1);
138 Opcodes add11_op = add11->Opcode();
139 if( (add1 == add1->in(1))
140 || (add11_op == this_op && add11->in(1) == add1) ) {
141 assert(false, "dead loop in AddNode::Ideal");
142 }
143 #endif
144 // The Add of the flattened expression
145 Node *x1 = add1->in(1);
146 Node *x2 = phase->makecon( add1->as_Add()->add_ring( t2, t12 ));
147 PhaseIterGVN *igvn = phase->is_IterGVN();
148 if( igvn ) {
149 set_req_X(2,x2,igvn);
150 set_req_X(1,x1,igvn);
151 } else {
152 set_req(2,x2);
153 set_req(1,x1);
154 }
155 progress = this; // Made progress
156 add1 = in(1);
157 add1_op = add1->Opcode();
158 }
159 }
160
161 // Convert "(x+1)+y" into "(x+y)+1". Push constants down the expression tree.
162 if( add1_op == this_op && !con_right ) {
163 Node *a12 = add1->in(2);
164 const Type *t12 = phase->type( a12 );
165 if( t12->singleton() && t12 != Type::TOP && (add1 != add1->in(1)) &&
166 !(add1->in(1)->is_Phi() && add1->in(1)->as_Phi()->is_tripcount()) ) {
167 assert(add1->in(1) != this, "dead loop in AddNode::Ideal");
168 add2 = add1->clone();
169 add2->set_req(2, in(2));
170 add2 = phase->transform(add2);
171 set_req(1, add2);
172 set_req(2, a12);
173 progress = this;
174 add2 = a12;
175 }
176 }
177
178 // Convert "x+(y+1)" into "(x+y)+1". Push constants down the expression tree.
179 Opcodes add2_op = add2->Opcode();
180 if( add2_op == this_op && !con_left ) {
181 Node *a22 = add2->in(2);
182 const Type *t22 = phase->type( a22 );
183 if( t22->singleton() && t22 != Type::TOP && (add2 != add2->in(1)) &&
184 !(add2->in(1)->is_Phi() && add2->in(1)->as_Phi()->is_tripcount()) ) {
185 assert(add2->in(1) != this, "dead loop in AddNode::Ideal");
186 Node *addx = add2->clone();
187 addx->set_req(1, in(1));
188 addx->set_req(2, add2->in(1));
189 addx = phase->transform(addx);
190 set_req(1, addx);
191 set_req(2, a22);
192 progress = this;
193 PhaseIterGVN *igvn = phase->is_IterGVN();
194 if (add2->outcnt() == 0 && igvn) {
195 // add disconnected.
196 igvn->_worklist.push(add2);
197 }
198 }
199 }
223
224 return add_ring(t1,t2); // Local flavor of type addition
225 }
226
227 //------------------------------add_identity-----------------------------------
228 // Check for addition of the identity
229 const Type *AddNode::add_of_identity( const Type *t1, const Type *t2 ) const {
230 const Type *zero = add_id(); // The additive identity
231 if( t1->higher_equal( zero ) ) return t2;
232 if( t2->higher_equal( zero ) ) return t1;
233
234 return NULL;
235 }
236
237
238 //=============================================================================
239 //------------------------------Idealize---------------------------------------
240 Node *AddINode::Ideal(PhaseGVN *phase, bool can_reshape) {
241 Node* in1 = in(1);
242 Node* in2 = in(2);
243 Opcodes op1 = in1->Opcode();
244 Opcodes op2 = in2->Opcode();
245 // Fold (con1-x)+con2 into (con1+con2)-x
246 if ( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_SubI ) {
247 // Swap edges to try optimizations below
248 in1 = in2;
249 in2 = in(1);
250 op1 = op2;
251 op2 = in2->Opcode();
252 }
253 if( op1 == Opcodes::Op_SubI ) {
254 const Type *t_sub1 = phase->type( in1->in(1) );
255 const Type *t_2 = phase->type( in2 );
256 if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
257 return new SubINode(phase->makecon( add_ring( t_sub1, t_2 ) ), in1->in(2) );
258 // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
259 if( op2 == Opcodes::Op_SubI ) {
260 // Check for dead cycle: d = (a-b)+(c-d)
261 assert( in1->in(2) != this && in2->in(2) != this,
262 "dead loop in AddINode::Ideal" );
263 Node *sub = new SubINode(NULL, NULL);
264 sub->init_req(1, phase->transform(new AddINode(in1->in(1), in2->in(1) ) ));
265 sub->init_req(2, phase->transform(new AddINode(in1->in(2), in2->in(2) ) ));
266 return sub;
267 }
268 // Convert "(a-b)+(b+c)" into "(a+c)"
269 if( op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(1) ) {
270 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
271 return new AddINode(in1->in(1), in2->in(2));
272 }
273 // Convert "(a-b)+(c+b)" into "(a+c)"
274 if( op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(2) ) {
275 assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
276 return new AddINode(in1->in(1), in2->in(1));
277 }
278 // Convert "(a-b)+(b-c)" into "(a-c)"
279 if( op2 == Opcodes::Op_SubI && in1->in(2) == in2->in(1) ) {
280 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddINode::Ideal");
281 return new SubINode(in1->in(1), in2->in(2));
282 }
283 // Convert "(a-b)+(c-a)" into "(c-b)"
284 if( op2 == Opcodes::Op_SubI && in1->in(1) == in2->in(2) ) {
285 assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddINode::Ideal");
286 return new SubINode(in2->in(1), in1->in(2));
287 }
288 }
289
290 // Convert "x+(0-y)" into "(x-y)"
291 if( op2 == Opcodes::Op_SubI && phase->type(in2->in(1)) == TypeInt::ZERO )
292 return new SubINode(in1, in2->in(2) );
293
294 // Convert "(0-y)+x" into "(x-y)"
295 if( op1 == Opcodes::Op_SubI && phase->type(in1->in(1)) == TypeInt::ZERO )
296 return new SubINode( in2, in1->in(2) );
297
298 // Convert (x>>>z)+y into (x+(y<<z))>>>z for small constant z and y.
299 // Helps with array allocation math constant folding
300 // See 4790063:
301 // Unrestricted transformation is unsafe for some runtime values of 'x'
302 // ( x == 0, z == 1, y == -1 ) fails
303 // ( x == -5, z == 1, y == 1 ) fails
304 // Transform works for small z and small negative y when the addition
305 // (x + (y << z)) does not cross zero.
306 // Implement support for negative y and (x >= -(y << z))
307 // Have not observed cases where type information exists to support
308 // positive y and (x <= -(y << z))
309 if( op1 == Opcodes::Op_URShiftI && op2 == Opcodes::Op_ConI &&
310 in1->in(2)->Opcode() == Opcodes::Op_ConI ) {
311 jint z = phase->type( in1->in(2) )->is_int()->get_con() & 0x1f; // only least significant 5 bits matter
312 jint y = phase->type( in2 )->is_int()->get_con();
313
314 if( z < 5 && -5 < y && y < 0 ) {
315 const Type *t_in11 = phase->type(in1->in(1));
316 if( t_in11 != Type::TOP && (t_in11->is_int()->_lo >= -(y << z)) ) {
317 Node *a = phase->transform( new AddINode( in1->in(1), phase->intcon(y<<z) ) );
318 return new URShiftINode( a, in1->in(2) );
319 }
320 }
321 }
322
323 return AddNode::Ideal(phase, can_reshape);
324 }
325
326
327 //------------------------------Identity---------------------------------------
328 // Fold (x-y)+y OR y+(x-y) into x
329 Node* AddINode::Identity(PhaseGVN* phase) {
330 if( in(1)->Opcode() == Opcodes::Op_SubI && phase->eqv(in(1)->in(2),in(2)) ) {
331 return in(1)->in(1);
332 }
333 else if( in(2)->Opcode() == Opcodes::Op_SubI && phase->eqv(in(2)->in(2),in(1)) ) {
334 return in(2)->in(1);
335 }
336 return AddNode::Identity(phase);
337 }
338
339
340 //------------------------------add_ring---------------------------------------
341 // Supplied function returns the sum of the inputs. Guaranteed never
342 // to be passed a TOP or BOTTOM type, these are filtered out by
343 // pre-check.
344 const Type *AddINode::add_ring( const Type *t0, const Type *t1 ) const {
345 const TypeInt *r0 = t0->is_int(); // Handy access
346 const TypeInt *r1 = t1->is_int();
347 int lo = java_add(r0->_lo, r1->_lo);
348 int hi = java_add(r0->_hi, r1->_hi);
349 if( !(r0->is_con() && r1->is_con()) ) {
350 // Not both constants, compute approximate result
351 if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
352 lo = min_jint; hi = max_jint; // Underflow on the low side
353 }
354 if( (~(r0->_hi | r1->_hi)) < 0 && hi < 0 ) {
355 lo = min_jint; hi = max_jint; // Overflow on the high side
356 }
357 if( lo > hi ) { // Handle overflow
358 lo = min_jint; hi = max_jint;
359 }
360 } else {
361 // both constants, compute precise result using 'lo' and 'hi'
362 // Semantics define overflow and underflow for integer addition
363 // as expected. In particular: 0x80000000 + 0x80000000 --> 0x0
364 }
365 return TypeInt::make( lo, hi, MAX2(r0->_widen,r1->_widen) );
366 }
367
368
369 //=============================================================================
370 //------------------------------Idealize---------------------------------------
371 Node *AddLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
372 Node* in1 = in(1);
373 Node* in2 = in(2);
374 Opcodes op1 = in1->Opcode();
375 Opcodes op2 = in2->Opcode();
376 // Fold (con1-x)+con2 into (con1+con2)-x
377 if ( op1 == Opcodes::Op_AddL && op2 == Opcodes::Op_SubL ) {
378 // Swap edges to try optimizations below
379 in1 = in2;
380 in2 = in(1);
381 op1 = op2;
382 op2 = in2->Opcode();
383 }
384 // Fold (con1-x)+con2 into (con1+con2)-x
385 if( op1 == Opcodes::Op_SubL ) {
386 const Type *t_sub1 = phase->type( in1->in(1) );
387 const Type *t_2 = phase->type( in2 );
388 if( t_sub1->singleton() && t_2->singleton() && t_sub1 != Type::TOP && t_2 != Type::TOP )
389 return new SubLNode(phase->makecon( add_ring( t_sub1, t_2 ) ), in1->in(2) );
390 // Convert "(a-b)+(c-d)" into "(a+c)-(b+d)"
391 if( op2 == Opcodes::Op_SubL ) {
392 // Check for dead cycle: d = (a-b)+(c-d)
393 assert( in1->in(2) != this && in2->in(2) != this,
394 "dead loop in AddLNode::Ideal" );
395 Node *sub = new SubLNode(NULL, NULL);
396 sub->init_req(1, phase->transform(new AddLNode(in1->in(1), in2->in(1) ) ));
397 sub->init_req(2, phase->transform(new AddLNode(in1->in(2), in2->in(2) ) ));
398 return sub;
399 }
400 // Convert "(a-b)+(b+c)" into "(a+c)"
401 if( op2 == Opcodes::Op_AddL && in1->in(2) == in2->in(1) ) {
402 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
403 return new AddLNode(in1->in(1), in2->in(2));
404 }
405 // Convert "(a-b)+(c+b)" into "(a+c)"
406 if( op2 == Opcodes::Op_AddL && in1->in(2) == in2->in(2) ) {
407 assert(in1->in(1) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
408 return new AddLNode(in1->in(1), in2->in(1));
409 }
410 // Convert "(a-b)+(b-c)" into "(a-c)"
411 if( op2 == Opcodes::Op_SubL && in1->in(2) == in2->in(1) ) {
412 assert(in1->in(1) != this && in2->in(2) != this,"dead loop in AddLNode::Ideal");
413 return new SubLNode(in1->in(1), in2->in(2));
414 }
415 // Convert "(a-b)+(c-a)" into "(c-b)"
416 if( op2 == Opcodes::Op_SubL && in1->in(1) == in1->in(2) ) {
417 assert(in1->in(2) != this && in2->in(1) != this,"dead loop in AddLNode::Ideal");
418 return new SubLNode(in2->in(1), in1->in(2));
419 }
420 }
421
422 // Convert "x+(0-y)" into "(x-y)"
423 if( op2 == Opcodes::Op_SubL && phase->type(in2->in(1)) == TypeLong::ZERO )
424 return new SubLNode( in1, in2->in(2) );
425
426 // Convert "(0-y)+x" into "(x-y)"
427 if( op1 == Opcodes::Op_SubL && phase->type(in1->in(1)) == TypeInt::ZERO )
428 return new SubLNode( in2, in1->in(2) );
429
430 // Convert "X+X+X+X+X...+X+Y" into "k*X+Y" or really convert "X+(X+Y)"
431 // into "(X<<1)+Y" and let shift-folding happen.
432 if( op2 == Opcodes::Op_AddL &&
433 in2->in(1) == in1 &&
434 op1 != Opcodes::Op_ConL &&
435 0 ) {
436 Node *shift = phase->transform(new LShiftLNode(in1,phase->intcon(1)));
437 return new AddLNode(shift,in2->in(2));
438 }
439
440 return AddNode::Ideal(phase, can_reshape);
441 }
442
443
444 //------------------------------Identity---------------------------------------
445 // Fold (x-y)+y OR y+(x-y) into x
446 Node* AddLNode::Identity(PhaseGVN* phase) {
447 if( in(1)->Opcode() == Opcodes::Op_SubL && phase->eqv(in(1)->in(2),in(2)) ) {
448 return in(1)->in(1);
449 }
450 else if( in(2)->Opcode() == Opcodes::Op_SubL && phase->eqv(in(2)->in(2),in(1)) ) {
451 return in(2)->in(1);
452 }
453 return AddNode::Identity(phase);
454 }
455
456
457 //------------------------------add_ring---------------------------------------
458 // Supplied function returns the sum of the inputs. Guaranteed never
459 // to be passed a TOP or BOTTOM type, these are filtered out by
460 // pre-check.
461 const Type *AddLNode::add_ring( const Type *t0, const Type *t1 ) const {
462 const TypeLong *r0 = t0->is_long(); // Handy access
463 const TypeLong *r1 = t1->is_long();
464 jlong lo = java_add(r0->_lo, r1->_lo);
465 jlong hi = java_add(r0->_hi, r1->_hi);
466 if( !(r0->is_con() && r1->is_con()) ) {
467 // Not both constants, compute approximate result
468 if( (r0->_lo & r1->_lo) < 0 && lo >= 0 ) {
469 lo =min_jlong; hi = max_jlong; // Underflow on the low side
470 }
606 set_req(Offset,offset);
607 }
608 return this;
609 }
610 }
611
612 // Raw pointers?
613 if( in(Base)->bottom_type() == Type::TOP ) {
614 // If this is a NULL+long form (from unsafe accesses), switch to a rawptr.
615 if (phase->type(in(Address)) == TypePtr::NULL_PTR) {
616 Node* offset = in(Offset);
617 return new CastX2PNode(offset);
618 }
619 }
620
621 // If the right is an add of a constant, push the offset down.
622 // Convert: (ptr + (offset+con)) into (ptr+offset)+con.
623 // The idea is to merge array_base+scaled_index groups together,
624 // and only have different constant offsets from the same base.
625 const Node *add = in(Offset);
626 if( add->Opcode() == Opcodes::Op_AddX && add->in(1) != add ) {
627 const Type *t22 = phase->type( add->in(2) );
628 if( t22->singleton() && (t22 != Type::TOP) ) { // Right input is an add of a constant?
629 set_req(Address, phase->transform(new AddPNode(in(Base),in(Address),add->in(1))));
630 set_req(Offset, add->in(2));
631 PhaseIterGVN *igvn = phase->is_IterGVN();
632 if (add->outcnt() == 0 && igvn) {
633 // add disconnected.
634 igvn->_worklist.push((Node*)add);
635 }
636 return this; // Made progress
637 }
638 }
639
640 return NULL; // No progress
641 }
642
643 //------------------------------bottom_type------------------------------------
644 // Bottom-type is the pointer-type with unknown offset.
645 const Type *AddPNode::bottom_type() const {
646 if (in(Address) == NULL) return TypePtr::BOTTOM;
647 const TypePtr *tp = in(Address)->bottom_type()->isa_ptr();
648 if( !tp ) return Type::TOP; // TOP input means TOP output
649 assert( in(Offset)->Opcode() != Opcodes::Op_ConP, "" );
650 const Type *t = in(Offset)->bottom_type();
651 if( t == Type::TOP )
652 return tp->add_offset(Type::OffsetTop);
653 const TypeX *tx = t->is_intptr_t();
654 intptr_t txoffset = Type::OffsetBot;
655 if (tx->is_con()) { // Left input is an add of a constant?
656 txoffset = tx->get_con();
657 }
658 return tp->add_offset(txoffset);
659 }
660
661 //------------------------------Value------------------------------------------
662 const Type* AddPNode::Value(PhaseGVN* phase) const {
663 // Either input is TOP ==> the result is TOP
664 const Type *t1 = phase->type( in(Address) );
665 const Type *t2 = phase->type( in(Offset) );
666 if( t1 == Type::TOP ) return Type::TOP;
667 if( t2 == Type::TOP ) return Type::TOP;
668
669 // Left input is a pointer
837 // Supplied function returns the sum of the inputs.
838 const Type *MaxINode::add_ring( const Type *t0, const Type *t1 ) const {
839 const TypeInt *r0 = t0->is_int(); // Handy access
840 const TypeInt *r1 = t1->is_int();
841
842 // Otherwise just MAX them bits.
843 return TypeInt::make( MAX2(r0->_lo,r1->_lo), MAX2(r0->_hi,r1->_hi), MAX2(r0->_widen,r1->_widen) );
844 }
845
846 //=============================================================================
847 //------------------------------Idealize---------------------------------------
848 // MINs show up in range-check loop limit calculations. Look for
849 // "MIN2(x+c0,MIN2(y,x+c1))". Pick the smaller constant: "MIN2(x+c0,y)"
850 Node *MinINode::Ideal(PhaseGVN *phase, bool can_reshape) {
851 Node *progress = NULL;
852 // Force a right-spline graph
853 Node *l = in(1);
854 Node *r = in(2);
855 // Transform MinI1( MinI2(a,b), c) into MinI1( a, MinI2(b,c) )
856 // to force a right-spline graph for the rest of MinINode::Ideal().
857 if( l->Opcode() == Opcodes::Op_MinI ) {
858 assert( l != l->in(1), "dead loop in MinINode::Ideal" );
859 r = phase->transform(new MinINode(l->in(2),r));
860 l = l->in(1);
861 set_req(1, l);
862 set_req(2, r);
863 return this;
864 }
865
866 // Get left input & constant
867 Node *x = l;
868 int x_off = 0;
869 if( x->Opcode() == Opcodes::Op_AddI && // Check for "x+c0" and collect constant
870 x->in(2)->is_Con() ) {
871 const Type *t = x->in(2)->bottom_type();
872 if( t == Type::TOP ) return NULL; // No progress
873 x_off = t->is_int()->get_con();
874 x = x->in(1);
875 }
876
877 // Scan a right-spline-tree for MINs
878 Node *y = r;
879 int y_off = 0;
880 // Check final part of MIN tree
881 if( y->Opcode() == Opcodes::Op_AddI && // Check for "y+c1" and collect constant
882 y->in(2)->is_Con() ) {
883 const Type *t = y->in(2)->bottom_type();
884 if( t == Type::TOP ) return NULL; // No progress
885 y_off = t->is_int()->get_con();
886 y = y->in(1);
887 }
888 if( x->_idx > y->_idx && r->Opcode() != Opcodes::Op_MinI ) {
889 swap_edges(1, 2);
890 return this;
891 }
892
893
894 if( r->Opcode() == Opcodes::Op_MinI ) {
895 assert( r != r->in(2), "dead loop in MinINode::Ideal" );
896 y = r->in(1);
897 // Check final part of MIN tree
898 if( y->Opcode() == Opcodes::Op_AddI &&// Check for "y+c1" and collect constant
899 y->in(2)->is_Con() ) {
900 const Type *t = y->in(2)->bottom_type();
901 if( t == Type::TOP ) return NULL; // No progress
902 y_off = t->is_int()->get_con();
903 y = y->in(1);
904 }
905
906 if( x->_idx > y->_idx )
907 return new MinINode(r->in(1),phase->transform(new MinINode(l,r->in(2))));
908
909 // See if covers: MIN2(x+c0,MIN2(y+c1,z))
910 if( !phase->eqv(x,y) ) return NULL;
911 // If (y == x) transform MIN2(x+c0, MIN2(x+c1,z)) into
912 // MIN2(x+c0 or x+c1 which less, z).
913 return new MinINode(phase->transform(new AddINode(x,phase->intcon(MIN2(x_off,y_off)))),r->in(2));
914 } else {
915 // See if covers: MIN2(x+c0,y+c1)
916 if( !phase->eqv(x,y) ) return NULL;
917 // If (y == x) transform MIN2(x+c0,x+c1) into x+c0 or x+c1 which less.
918 return new AddINode(x,phase->intcon(MIN2(x_off,y_off)));
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