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## src/share/vm/opto/subnode.cpp

 ``` `````` 42 // Optimization - Graph Style 43 44 #include "math.h" 45 46 //============================================================================= 47 //------------------------------Identity--------------------------------------- 48 // If right input is a constant 0, return the left input. 49 Node* SubNode::Identity(PhaseGVN* phase) { 50 assert(in(1) != this, "Must already have called Value"); 51 assert(in(2) != this, "Must already have called Value"); 52 53 // Remove double negation 54 const Type *zero = add_id(); 55 if( phase->type( in(1) )->higher_equal( zero ) && 56 in(2)->Opcode() == Opcode() && 57 phase->type( in(2)->in(1) )->higher_equal( zero ) ) { 58 return in(2)->in(2); 59 } 60 61 // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y 62 if( in(1)->Opcode() == Op_AddI ) { 63 if( phase->eqv(in(1)->in(2),in(2)) ) 64 return in(1)->in(1); 65 if (phase->eqv(in(1)->in(1),in(2))) 66 return in(1)->in(2); 67 68 // Also catch: "(X + Opaque2(Y)) - Y". In this case, 'Y' is a loop-varying 69 // trip counter and X is likely to be loop-invariant (that's how O2 Nodes 70 // are originally used, although the optimizer sometimes jiggers things). 71 // This folding through an O2 removes a loop-exit use of a loop-varying 72 // value and generally lowers register pressure in and around the loop. 73 if( in(1)->in(2)->Opcode() == Op_Opaque2 && 74 phase->eqv(in(1)->in(2)->in(1),in(2)) ) 75 return in(1)->in(1); 76 } 77 78 return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this; 79 } 80 81 //------------------------------Value------------------------------------------ 82 // A subtract node differences it's two inputs. 83 const Type* SubNode::Value_common(PhaseTransform *phase) const { 84 const Node* in1 = in(1); 85 const Node* in2 = in(2); 86 // Either input is TOP ==> the result is TOP 87 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 88 if( t1 == Type::TOP ) return Type::TOP; 89 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 90 if( t2 == Type::TOP ) return Type::TOP; 91 92 // Not correct for SubFnode and AddFNode (must check for infinity) 93 // Equal? Subtract is zero `````` 124 const PhiNode *phi; 125 if( ( !inc->in(1)->is_Phi() || 126 !(phi=inc->in(1)->as_Phi()) || 127 phi->is_copy() || 128 !phi->region()->is_CountedLoop() || 129 inc != phi->region()->as_CountedLoop()->incr() ) 130 && 131 // Do not collapse (x+c0)-iv if "iv" is a loop induction variable, 132 // because "x" maybe invariant. 133 ( !iv->is_loop_iv() ) 134 ) { 135 return true; 136 } else { 137 return false; 138 } 139 } 140 //------------------------------Ideal------------------------------------------ 141 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){ 142 Node *in1 = in(1); 143 Node *in2 = in(2); 144 uint op1 = in1->Opcode(); 145 uint op2 = in2->Opcode(); 146 147 #ifdef ASSERT 148 // Check for dead loop 149 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 150 ( op1 == Op_AddI || op1 == Op_SubI ) && 151 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 152 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 153 assert(false, "dead loop in SubINode::Ideal"); 154 #endif 155 156 const Type *t2 = phase->type( in2 ); 157 if( t2 == Type::TOP ) return NULL; 158 // Convert "x-c0" into "x+ -c0". 159 if( t2->base() == Type::Int ){ // Might be bottom or top... 160 const TypeInt *i = t2->is_int(); 161 if( i->is_con() ) 162 return new AddINode(in1, phase->intcon(-i->get_con())); 163 } 164 165 // Convert "(x+c0) - y" into (x-y) + c0" 166 // Do not collapse (x+c0)-y if "+" is a loop increment or 167 // if "y" is a loop induction variable. 168 if( op1 == Op_AddI && ok_to_convert(in1, in2) ) { 169 const Type *tadd = phase->type( in1->in(2) ); 170 if( tadd->singleton() && tadd != Type::TOP ) { 171 Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 )); 172 return new AddINode( sub2, in1->in(2) ); 173 } 174 } 175 176 177 // Convert "x - (y+c0)" into "(x-y) - c0" 178 // Need the same check as in above optimization but reversed. 179 if (op2 == Op_AddI && ok_to_convert(in2, in1)) { 180 Node* in21 = in2->in(1); 181 Node* in22 = in2->in(2); 182 const TypeInt* tcon = phase->type(in22)->isa_int(); 183 if (tcon != NULL && tcon->is_con()) { 184 Node* sub2 = phase->transform( new SubINode(in1, in21) ); 185 Node* neg_c0 = phase->intcon(- tcon->get_con()); 186 return new AddINode(sub2, neg_c0); 187 } 188 } 189 190 const Type *t1 = phase->type( in1 ); 191 if( t1 == Type::TOP ) return NULL; 192 193 #ifdef ASSERT 194 // Check for dead loop 195 if( ( op2 == Op_AddI || op2 == Op_SubI ) && 196 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 197 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 198 assert(false, "dead loop in SubINode::Ideal"); 199 #endif 200 201 // Convert "x - (x+y)" into "-y" 202 if( op2 == Op_AddI && 203 phase->eqv( in1, in2->in(1) ) ) 204 return new SubINode( phase->intcon(0),in2->in(2)); 205 // Convert "(x-y) - x" into "-y" 206 if( op1 == Op_SubI && 207 phase->eqv( in1->in(1), in2 ) ) 208 return new SubINode( phase->intcon(0),in1->in(2)); 209 // Convert "x - (y+x)" into "-y" 210 if( op2 == Op_AddI && 211 phase->eqv( in1, in2->in(2) ) ) 212 return new SubINode( phase->intcon(0),in2->in(1)); 213 214 // Convert "0 - (x-y)" into "y-x" 215 if( t1 == TypeInt::ZERO && op2 == Op_SubI ) 216 return new SubINode( in2->in(2), in2->in(1) ); 217 218 // Convert "0 - (x+con)" into "-con-x" 219 jint con; 220 if( t1 == TypeInt::ZERO && op2 == Op_AddI && 221 (con = in2->in(2)->find_int_con(0)) != 0 ) 222 return new SubINode( phase->intcon(-con), in2->in(1) ); 223 224 // Convert "(X+A) - (X+B)" into "A - B" 225 if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(1) ) 226 return new SubINode( in1->in(2), in2->in(2) ); 227 228 // Convert "(A+X) - (B+X)" into "A - B" 229 if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(2) ) 230 return new SubINode( in1->in(1), in2->in(1) ); 231 232 // Convert "(A+X) - (X+B)" into "A - B" 233 if( op1 == Op_AddI && op2 == Op_AddI && in1->in(2) == in2->in(1) ) 234 return new SubINode( in1->in(1), in2->in(2) ); 235 236 // Convert "(X+A) - (B+X)" into "A - B" 237 if( op1 == Op_AddI && op2 == Op_AddI && in1->in(1) == in2->in(2) ) 238 return new SubINode( in1->in(2), in2->in(1) ); 239 240 // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally 241 // nicer to optimize than subtract. 242 if( op2 == Op_SubI && in2->outcnt() == 1) { 243 Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) ); 244 return new SubINode( add1, in2->in(1) ); 245 } 246 247 return NULL; 248 } 249 250 //------------------------------sub-------------------------------------------- 251 // A subtract node differences it's two inputs. 252 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const { 253 const TypeInt *r0 = t1->is_int(); // Handy access 254 const TypeInt *r1 = t2->is_int(); 255 int32_t lo = java_subtract(r0->_lo, r1->_hi); 256 int32_t hi = java_subtract(r0->_hi, r1->_lo); 257 258 // We next check for 32-bit overflow. 259 // If that happens, we just assume all integers are possible. 260 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 261 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 262 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR 263 ((r0->_hi ^ hi) >= 0)) ) // hi results have same signs 264 return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen)); 265 else // Overflow; assume all integers 266 return TypeInt::INT; 267 } 268 269 //============================================================================= 270 //------------------------------Ideal------------------------------------------ 271 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 272 Node *in1 = in(1); 273 Node *in2 = in(2); 274 uint op1 = in1->Opcode(); 275 uint op2 = in2->Opcode(); 276 277 #ifdef ASSERT 278 // Check for dead loop 279 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 280 ( op1 == Op_AddL || op1 == Op_SubL ) && 281 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 282 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 283 assert(false, "dead loop in SubLNode::Ideal"); 284 #endif 285 286 if( phase->type( in2 ) == Type::TOP ) return NULL; 287 const TypeLong *i = phase->type( in2 )->isa_long(); 288 // Convert "x-c0" into "x+ -c0". 289 if( i && // Might be bottom or top... 290 i->is_con() ) 291 return new AddLNode(in1, phase->longcon(-i->get_con())); 292 293 // Convert "(x+c0) - y" into (x-y) + c0" 294 // Do not collapse (x+c0)-y if "+" is a loop increment or 295 // if "y" is a loop induction variable. 296 if( op1 == Op_AddL && ok_to_convert(in1, in2) ) { 297 Node *in11 = in1->in(1); 298 const Type *tadd = phase->type( in1->in(2) ); 299 if( tadd->singleton() && tadd != Type::TOP ) { 300 Node *sub2 = phase->transform( new SubLNode( in11, in2 )); 301 return new AddLNode( sub2, in1->in(2) ); 302 } 303 } 304 305 // Convert "x - (y+c0)" into "(x-y) - c0" 306 // Need the same check as in above optimization but reversed. 307 if (op2 == Op_AddL && ok_to_convert(in2, in1)) { 308 Node* in21 = in2->in(1); 309 Node* in22 = in2->in(2); 310 const TypeLong* tcon = phase->type(in22)->isa_long(); 311 if (tcon != NULL && tcon->is_con()) { 312 Node* sub2 = phase->transform( new SubLNode(in1, in21) ); 313 Node* neg_c0 = phase->longcon(- tcon->get_con()); 314 return new AddLNode(sub2, neg_c0); 315 } 316 } 317 318 const Type *t1 = phase->type( in1 ); 319 if( t1 == Type::TOP ) return NULL; 320 321 #ifdef ASSERT 322 // Check for dead loop 323 if( ( op2 == Op_AddL || op2 == Op_SubL ) && 324 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 325 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 326 assert(false, "dead loop in SubLNode::Ideal"); 327 #endif 328 329 // Convert "x - (x+y)" into "-y" 330 if( op2 == Op_AddL && 331 phase->eqv( in1, in2->in(1) ) ) 332 return new SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2)); 333 // Convert "x - (y+x)" into "-y" 334 if( op2 == Op_AddL && 335 phase->eqv( in1, in2->in(2) ) ) 336 return new SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1)); 337 338 // Convert "0 - (x-y)" into "y-x" 339 if( phase->type( in1 ) == TypeLong::ZERO && op2 == Op_SubL ) 340 return new SubLNode( in2->in(2), in2->in(1) ); 341 342 // Convert "(X+A) - (X+B)" into "A - B" 343 if( op1 == Op_AddL && op2 == Op_AddL && in1->in(1) == in2->in(1) ) 344 return new SubLNode( in1->in(2), in2->in(2) ); 345 346 // Convert "(A+X) - (B+X)" into "A - B" 347 if( op1 == Op_AddL && op2 == Op_AddL && in1->in(2) == in2->in(2) ) 348 return new SubLNode( in1->in(1), in2->in(1) ); 349 350 // Convert "A-(B-C)" into (A+C)-B" 351 if( op2 == Op_SubL && in2->outcnt() == 1) { 352 Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) ); 353 return new SubLNode( add1, in2->in(1) ); 354 } 355 356 return NULL; 357 } 358 359 //------------------------------sub-------------------------------------------- 360 // A subtract node differences it's two inputs. 361 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const { 362 const TypeLong *r0 = t1->is_long(); // Handy access 363 const TypeLong *r1 = t2->is_long(); 364 jlong lo = java_subtract(r0->_lo, r1->_hi); 365 jlong hi = java_subtract(r0->_hi, r1->_lo); 366 367 // We next check for 32-bit overflow. 368 // If that happens, we just assume all integers are possible. 369 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 370 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 371 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR `````` 611 // (This is a gross hack, since the sub method never 612 // looks at the structure of the node in any other case.) 613 if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check()) 614 return TypeInt::CC_LT; 615 return TypeInt::CC; // else use worst case results 616 } 617 618 const Type* CmpUNode::Value(PhaseGVN* phase) const { 619 const Type* t = SubNode::Value_common(phase); 620 if (t != NULL) { 621 return t; 622 } 623 const Node* in1 = in(1); 624 const Node* in2 = in(2); 625 const Type* t1 = phase->type(in1); 626 const Type* t2 = phase->type(in2); 627 assert(t1->isa_int(), "CmpU has only Int type inputs"); 628 if (t2 == TypeInt::INT) { // Compare to bottom? 629 return bottom_type(); 630 } 631 uint in1_op = in1->Opcode(); 632 if (in1_op == Op_AddI || in1_op == Op_SubI) { 633 // The problem rise when result of AddI(SubI) may overflow 634 // signed integer value. Let say the input type is 635 // [256, maxint] then +128 will create 2 ranges due to 636 // overflow: [minint, minint+127] and [384, maxint]. 637 // But C2 type system keep only 1 type range and as result 638 // it use general [minint, maxint] for this case which we 639 // can't optimize. 640 // 641 // Make 2 separate type ranges based on types of AddI(SubI) inputs 642 // and compare results of their compare. If results are the same 643 // CmpU node can be optimized. 644 const Node* in11 = in1->in(1); 645 const Node* in12 = in1->in(2); 646 const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11); 647 const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12); 648 // Skip cases when input types are top or bottom. 649 if ((t11 != Type::TOP) && (t11 != TypeInt::INT) && 650 (t12 != Type::TOP) && (t12 != TypeInt::INT)) { 651 const TypeInt *r0 = t11->is_int(); 652 const TypeInt *r1 = t12->is_int(); 653 jlong lo_r0 = r0->_lo; 654 jlong hi_r0 = r0->_hi; 655 jlong lo_r1 = r1->_lo; 656 jlong hi_r1 = r1->_hi; 657 if (in1_op == Op_SubI) { 658 jlong tmp = hi_r1; 659 hi_r1 = -lo_r1; 660 lo_r1 = -tmp; 661 // Note, for substructing [minint,x] type range 662 // long arithmetic provides correct overflow answer. 663 // The confusion come from the fact that in 32-bit 664 // -minint == minint but in 64-bit -minint == maxint+1. 665 } 666 jlong lo_long = lo_r0 + lo_r1; 667 jlong hi_long = hi_r0 + hi_r1; 668 int lo_tr1 = min_jint; 669 int hi_tr1 = (int)hi_long; 670 int lo_tr2 = (int)lo_long; 671 int hi_tr2 = max_jint; 672 bool underflow = lo_long != (jlong)lo_tr2; 673 bool overflow = hi_long != (jlong)hi_tr1; 674 // Use sub(t1, t2) when there is no overflow (one type range) 675 // or when both overflow and underflow (too complex). 676 if ((underflow != overflow) && (hi_tr1 < lo_tr2)) { 677 // Overflow only on one boundary, compare 2 separate type ranges. 678 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 679 const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w); 680 const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w); 681 const Type* cmp1 = sub(tr1, t2); 682 const Type* cmp2 = sub(tr2, t2); 683 if (cmp1 == cmp2) { 684 return cmp1; // Hit! 685 } 686 } 687 } 688 } 689 690 return sub(t1, t2); // Local flavor of type subtraction 691 } 692 693 bool CmpUNode::is_index_range_check() const { 694 // Check for the "(X ModI Y) CmpU Y" shape 695 return (in(1)->Opcode() == Op_ModI && 696 in(1)->in(2)->eqv_uncast(in(2))); 697 } 698 699 //------------------------------Idealize--------------------------------------- 700 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) { 701 if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) { 702 switch (in(1)->Opcode()) { 703 case Op_CmpL3: // Collapse a CmpL3/CmpI into a CmpL 704 return new CmpLNode(in(1)->in(1),in(1)->in(2)); 705 case Op_CmpF3: // Collapse a CmpF3/CmpI into a CmpF 706 return new CmpFNode(in(1)->in(1),in(1)->in(2)); 707 case Op_CmpD3: // Collapse a CmpD3/CmpI into a CmpD 708 return new CmpDNode(in(1)->in(1),in(1)->in(2)); 709 //case Op_SubI: 710 // If (x - y) cannot overflow, then ((x - y) 0) 711 // can be turned into (x y). 712 // This is handled (with more general cases) by Ideal_sub_algebra. 713 } 714 } 715 return NULL; // No change 716 } 717 718 719 //============================================================================= 720 // Simplify a CmpL (compare 2 longs ) node, based on local information. 721 // If both inputs are constants, compare them. 722 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const { 723 const TypeLong *r0 = t1->is_long(); // Handy access 724 const TypeLong *r1 = t2->is_long(); 725 726 if( r0->_hi < r1->_lo ) // Range is always low? 727 return TypeInt::CC_LT; `````` 809 810 // Known constants can be compared exactly 811 // Null can be distinguished from any NotNull pointers 812 // Unknown inputs makes an unknown result 813 if( r0->singleton() ) { 814 intptr_t bits0 = r0->get_con(); 815 if( r1->singleton() ) 816 return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT; 817 return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC; 818 } else if( r1->singleton() ) { 819 intptr_t bits1 = r1->get_con(); 820 return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC; 821 } else 822 return TypeInt::CC; 823 } 824 825 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) { 826 // Return the klass node for 827 // LoadP(AddP(foo:Klass, #java_mirror)) 828 // or NULL if not matching. 829 if (n->Opcode() != Op_LoadP) return NULL; 830 831 const TypeInstPtr* tp = phase->type(n)->isa_instptr(); 832 if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL; 833 834 Node* adr = n->in(MemNode::Address); 835 intptr_t off = 0; 836 Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off); 837 if (k == NULL) return NULL; 838 const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr(); 839 if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL; 840 841 // We've found the klass node of a Java mirror load. 842 return k; 843 } 844 845 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) { 846 // for ConP(Foo.class) return ConP(Foo.klass) 847 // otherwise return NULL 848 if (!n->is_Con()) return NULL; 849 `````` 894 if (k1 && (k2 || conk2)) { 895 Node* lhs = k1; 896 Node* rhs = (k2 != NULL) ? k2 : conk2; 897 this->set_req(1, lhs); 898 this->set_req(2, rhs); 899 return this; 900 } 901 } 902 903 // Constant pointer on right? 904 const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr(); 905 if (t2 == NULL || !t2->klass_is_exact()) 906 return NULL; 907 // Get the constant klass we are comparing to. 908 ciKlass* superklass = t2->klass(); 909 910 // Now check for LoadKlass on left. 911 Node* ldk1 = in(1); 912 if (ldk1->is_DecodeNKlass()) { 913 ldk1 = ldk1->in(1); 914 if (ldk1->Opcode() != Op_LoadNKlass ) 915 return NULL; 916 } else if (ldk1->Opcode() != Op_LoadKlass ) 917 return NULL; 918 // Take apart the address of the LoadKlass: 919 Node* adr1 = ldk1->in(MemNode::Address); 920 intptr_t con2 = 0; 921 Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2); 922 if (ldk2 == NULL) 923 return NULL; 924 if (con2 == oopDesc::klass_offset_in_bytes()) { 925 // We are inspecting an object's concrete class. 926 // Short-circuit the check if the query is abstract. 927 if (superklass->is_interface() || 928 superklass->is_abstract()) { 929 // Make it come out always false: 930 this->set_req(2, phase->makecon(TypePtr::NULL_PTR)); 931 return this; 932 } 933 } 934 935 // Check for a LoadKlass from primary supertype array. 936 // Any nested loadklass from loadklass+con must be from the p.s. array. 937 if (ldk2->is_DecodeNKlass()) { 938 // Keep ldk2 as DecodeN since it could be used in CmpP below. 939 if (ldk2->in(1)->Opcode() != Op_LoadNKlass ) 940 return NULL; 941 } else if (ldk2->Opcode() != Op_LoadKlass) 942 return NULL; 943 944 // Verify that we understand the situation 945 if (con2 != (intptr_t) superklass->super_check_offset()) 946 return NULL; // Might be element-klass loading from array klass 947 948 // If 'superklass' has no subklasses and is not an interface, then we are 949 // assured that the only input which will pass the type check is 950 // 'superklass' itself. 951 // 952 // We could be more liberal here, and allow the optimization on interfaces 953 // which have a single implementor. This would require us to increase the 954 // expressiveness of the add_dependency() mechanism. 955 // %%% Do this after we fix TypeOopPtr: Deps are expressive enough now. 956 957 // Object arrays must have their base element have no subtypes 958 while (superklass->is_obj_array_klass()) { 959 ciType* elem = superklass->as_obj_array_klass()->element_type(); 960 superklass = elem->as_klass(); 961 } ``````1106 if( td1->is_nan() || td2->is_nan() ) 1107 return TypeInt::CC_LT; 1108 1109 if( td1->_d < td2->_d ) return TypeInt::CC_LT; 1110 if( td1->_d > td2->_d ) return TypeInt::CC_GT; 1111 assert( td1->_d == td2->_d, "do not understand FP behavior" ); 1112 return TypeInt::CC_EQ; 1113 } 1114 1115 //------------------------------Ideal------------------------------------------ 1116 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){ 1117 // Check if we can change this to a CmpF and remove a ConvD2F operation. 1118 // Change (CMPD (F2D (float)) (ConD value)) 1119 // To (CMPF (float) (ConF value)) 1120 // Valid when 'value' does not lose precision as a float. 1121 // Benefits: eliminates conversion, does not require 24-bit mode 1122 1123 // NaNs prevent commuting operands. This transform works regardless of the 1124 // order of ConD and ConvF2D inputs by preserving the original order. 1125 int idx_f2d = 1; // ConvF2D on left side? 1126 if( in(idx_f2d)->Opcode() != Op_ConvF2D ) 1127 idx_f2d = 2; // No, swap to check for reversed args 1128 int idx_con = 3-idx_f2d; // Check for the constant on other input 1129 1130 if( ConvertCmpD2CmpF && 1131 in(idx_f2d)->Opcode() == Op_ConvF2D && 1132 in(idx_con)->Opcode() == Op_ConD ) { 1133 const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant(); 1134 double t2_value_as_double = t2->_d; 1135 float t2_value_as_float = (float)t2_value_as_double; 1136 if( t2_value_as_double == (double)t2_value_as_float ) { 1137 // Test value can be represented as a float 1138 // Eliminate the conversion to double and create new comparison 1139 Node *new_in1 = in(idx_f2d)->in(1); 1140 Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) ); 1141 if( idx_f2d != 1 ) { // Must flip args to match original order 1142 Node *tmp = new_in1; 1143 new_in1 = new_in2; 1144 new_in2 = tmp; 1145 } 1146 CmpFNode *new_cmp = (Opcode() == Op_CmpD3) 1147 ? new CmpF3Node( new_in1, new_in2 ) 1148 : new CmpFNode ( new_in1, new_in2 ) ; 1149 return new_cmp; // Changed to CmpFNode 1150 } 1151 // Testing value required the precision of a double 1152 } 1153 return NULL; // No change 1154 } 1155 1156 1157 //============================================================================= 1158 //------------------------------cc2logical------------------------------------- 1159 // Convert a condition code type to a logical type 1160 const Type *BoolTest::cc2logical( const Type *CC ) const { 1161 if( CC == Type::TOP ) return Type::TOP; 1162 if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse 1163 const TypeInt *ti = CC->is_int(); 1164 if( ti->is_con() ) { // Only 1 kind of condition codes set? 1165 // Match low order 2 bits 1166 int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0; ``````1220 return phase->transform(bol); 1221 } 1222 1223 //--------------------------------as_int_value--------------------------------- 1224 Node* BoolNode::as_int_value(PhaseGVN* phase) { 1225 // Inverse to make_predicate. The CMove probably boils down to a Conv2B. 1226 Node* cmov = CMoveNode::make(NULL, this, 1227 phase->intcon(0), phase->intcon(1), 1228 TypeInt::BOOL); 1229 return phase->transform(cmov); 1230 } 1231 1232 //----------------------------------negate------------------------------------- 1233 BoolNode* BoolNode::negate(PhaseGVN* phase) { 1234 return new BoolNode(in(1), _test.negate()); 1235 } 1236 1237 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub 1238 // overflows and we can prove that C is not in the two resulting ranges. 1239 // This optimization is similar to the one performed by CmpUNode::Value(). 1240 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, int cmp_op, 1241 int cmp1_op, const TypeInt* cmp2_type) { 1242 // Only optimize eq/ne integer comparison of add/sub 1243 if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1244 (cmp_op == Op_CmpI) && (cmp1_op == Op_AddI || cmp1_op == Op_SubI)) { 1245 // Skip cases were inputs of add/sub are not integers or of bottom type 1246 const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int(); 1247 const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int(); 1248 if ((r0 != NULL) && (r0 != TypeInt::INT) && 1249 (r1 != NULL) && (r1 != TypeInt::INT) && 1250 (cmp2_type != TypeInt::INT)) { 1251 // Compute exact (long) type range of add/sub result 1252 jlong lo_long = r0->_lo; 1253 jlong hi_long = r0->_hi; 1254 if (cmp1_op == Op_AddI) { 1255 lo_long += r1->_lo; 1256 hi_long += r1->_hi; 1257 } else { 1258 lo_long -= r1->_hi; 1259 hi_long -= r1->_lo; 1260 } 1261 // Check for over-/underflow by casting to integer 1262 int lo_int = (int)lo_long; 1263 int hi_int = (int)hi_long; 1264 bool underflow = lo_long != (jlong)lo_int; 1265 bool overflow = hi_long != (jlong)hi_int; 1266 if ((underflow != overflow) && (hi_int < lo_int)) { 1267 // Overflow on one boundary, compute resulting type ranges: 1268 // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT] 1269 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 1270 const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w); 1271 const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w); 1272 // Compare second input of cmp to both type ranges 1273 const Type* sub_tr1 = cmp->sub(tr1, cmp2_type); 1274 const Type* sub_tr2 = cmp->sub(tr2, cmp2_type); 1275 if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) { 1276 // The result of the add/sub will never equal cmp2. Replace BoolNode 1277 // by false (0) if it tests for equality and by true (1) otherwise. 1278 return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1); 1279 } 1280 } 1281 } 1282 } 1283 return NULL; 1284 } 1285 1286 //------------------------------Ideal------------------------------------------ 1287 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1288 // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)". 1289 // This moves the constant to the right. Helps value-numbering. 1290 Node *cmp = in(1); 1291 if( !cmp->is_Sub() ) return NULL; 1292 int cop = cmp->Opcode(); 1293 if( cop == Op_FastLock || cop == Op_FastUnlock) return NULL; 1294 Node *cmp1 = cmp->in(1); 1295 Node *cmp2 = cmp->in(2); 1296 if( !cmp1 ) return NULL; 1297 1298 if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) { 1299 return NULL; 1300 } 1301 1302 // Constant on left? 1303 Node *con = cmp1; 1304 uint op2 = cmp2->Opcode(); 1305 // Move constants to the right of compare's to canonicalize. 1306 // Do not muck with Opaque1 nodes, as this indicates a loop 1307 // guard that cannot change shape. 1308 if( con->is_Con() && !cmp2->is_Con() && op2 != Op_Opaque1 && 1309 // Because of NaN's, CmpD and CmpF are not commutative 1310 cop != Op_CmpD && cop != Op_CmpF && 1311 // Protect against swapping inputs to a compare when it is used by a 1312 // counted loop exit, which requires maintaining the loop-limit as in(2) 1313 !is_counted_loop_exit_test() ) { 1314 // Ok, commute the constant to the right of the cmp node. 1315 // Clone the Node, getting a new Node of the same class 1316 cmp = cmp->clone(); 1317 // Swap inputs to the clone 1318 cmp->swap_edges(1, 2); 1319 cmp = phase->transform( cmp ); 1320 return new BoolNode( cmp, _test.commute() ); 1321 } 1322 1323 // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)". 1324 // The XOR-1 is an idiom used to flip the sense of a bool. We flip the 1325 // test instead. 1326 int cmp1_op = cmp1->Opcode(); 1327 const TypeInt* cmp2_type = phase->type(cmp2)->isa_int(); 1328 if (cmp2_type == NULL) return NULL; 1329 Node* j_xor = cmp1; 1330 if( cmp2_type == TypeInt::ZERO && 1331 cmp1_op == Op_XorI && 1332 j_xor->in(1) != j_xor && // An xor of itself is dead 1333 phase->type( j_xor->in(1) ) == TypeInt::BOOL && 1334 phase->type( j_xor->in(2) ) == TypeInt::ONE && 1335 (_test._test == BoolTest::eq || 1336 _test._test == BoolTest::ne) ) { 1337 Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2)); 1338 return new BoolNode( ncmp, _test.negate() ); 1339 } 1340 1341 // Change ((x & m) u<= m) or ((m & x) u<= m) to always true 1342 // Same with ((x & m) u< m+1) and ((m & x) u< m+1) 1343 if (cop == Op_CmpU && 1344 cmp1->Opcode() == Op_AndI) { 1345 Node* bound = NULL; 1346 if (_test._test == BoolTest::le) { 1347 bound = cmp2; 1348 } else if (_test._test == BoolTest::lt && 1349 cmp2->Opcode() == Op_AddI && 1350 cmp2->in(2)->find_int_con(0) == 1) { 1351 bound = cmp2->in(1); 1352 } 1353 if (cmp1->in(2) == bound || cmp1->in(1) == bound) { 1354 return ConINode::make(1); 1355 } 1356 } 1357 1358 // Change ((x & (m - 1)) u< m) into (m > 0) 1359 // This is the off-by-one variant of the above 1360 if (cop == Op_CmpU && 1361 _test._test == BoolTest::lt && 1362 cmp1->Opcode() == Op_AndI) { 1363 Node* l = cmp1->in(1); 1364 Node* r = cmp1->in(2); 1365 for (int repeat = 0; repeat < 2; repeat++) { 1366 bool match = r->Opcode() == Op_AddI && r->in(2)->find_int_con(0) == -1 && 1367 r->in(1) == cmp2; 1368 if (match) { 1369 // arraylength known to be non-negative, so a (arraylength != 0) is sufficient, 1370 // but to be compatible with the array range check pattern, use (arraylength u> 0) 1371 Node* ncmp = cmp2->Opcode() == Op_LoadRange 1372 ? phase->transform(new CmpUNode(cmp2, phase->intcon(0))) 1373 : phase->transform(new CmpINode(cmp2, phase->intcon(0))); 1374 return new BoolNode(ncmp, BoolTest::gt); 1375 } else { 1376 // commute and try again 1377 l = cmp1->in(2); 1378 r = cmp1->in(1); 1379 } 1380 } 1381 } 1382 1383 // Change (arraylength <= 0) or (arraylength == 0) 1384 // into (arraylength u<= 0) 1385 // Also change (arraylength != 0) into (arraylength u> 0) 1386 // The latter version matches the code pattern generated for 1387 // array range checks, which will more likely be optimized later. 1388 if (cop == Op_CmpI && 1389 cmp1->Opcode() == Op_LoadRange && 1390 cmp2->find_int_con(-1) == 0) { 1391 if (_test._test == BoolTest::le || _test._test == BoolTest::eq) { 1392 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1393 return new BoolNode(ncmp, BoolTest::le); 1394 } else if (_test._test == BoolTest::ne) { 1395 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1396 return new BoolNode(ncmp, BoolTest::gt); 1397 } 1398 } 1399 1400 // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)". 1401 // This is a standard idiom for branching on a boolean value. 1402 Node *c2b = cmp1; 1403 if( cmp2_type == TypeInt::ZERO && 1404 cmp1_op == Op_Conv2B && 1405 (_test._test == BoolTest::eq || 1406 _test._test == BoolTest::ne) ) { 1407 Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int() 1408 ? (Node*)new CmpINode(c2b->in(1),cmp2) 1409 : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR)) 1410 ); 1411 return new BoolNode( ncmp, _test._test ); 1412 } 1413 1414 // Comparing a SubI against a zero is equal to comparing the SubI 1415 // arguments directly. This only works for eq and ne comparisons 1416 // due to possible integer overflow. 1417 if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1418 (cop == Op_CmpI) && 1419 (cmp1->Opcode() == Op_SubI) && 1420 ( cmp2_type == TypeInt::ZERO ) ) { 1421 Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2))); 1422 return new BoolNode( ncmp, _test._test ); 1423 } 1424 1425 // Change (-A vs 0) into (A vs 0) by commuting the test. Disallow in the 1426 // most general case because negating 0x80000000 does nothing. Needed for 1427 // the CmpF3/SubI/CmpI idiom. 1428 if( cop == Op_CmpI && 1429 cmp1->Opcode() == Op_SubI && 1430 cmp2_type == TypeInt::ZERO && 1431 phase->type( cmp1->in(1) ) == TypeInt::ZERO && 1432 phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) { 1433 Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2)); 1434 return new BoolNode( ncmp, _test.commute() ); 1435 } 1436 1437 // Try to optimize signed integer comparison 1438 return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type); 1439 1440 // The transformation below is not valid for either signed or unsigned 1441 // comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE. 1442 // This transformation can be resurrected when we are able to 1443 // make inferences about the range of values being subtracted from 1444 // (or added to) relative to the wraparound point. 1445 // 1446 // // Remove +/-1's if possible. 1447 // // "X <= Y-1" becomes "X < Y" 1448 // // "X+1 <= Y" becomes "X < Y" 1449 // // "X < Y+1" becomes "X <= Y" ``` ``` `````` 42 // Optimization - Graph Style 43 44 #include "math.h" 45 46 //============================================================================= 47 //------------------------------Identity--------------------------------------- 48 // If right input is a constant 0, return the left input. 49 Node* SubNode::Identity(PhaseGVN* phase) { 50 assert(in(1) != this, "Must already have called Value"); 51 assert(in(2) != this, "Must already have called Value"); 52 53 // Remove double negation 54 const Type *zero = add_id(); 55 if( phase->type( in(1) )->higher_equal( zero ) && 56 in(2)->Opcode() == Opcode() && 57 phase->type( in(2)->in(1) )->higher_equal( zero ) ) { 58 return in(2)->in(2); 59 } 60 61 // Convert "(X+Y) - Y" into X and "(X+Y) - X" into Y 62 if( in(1)->Opcode() == Opcodes::Op_AddI ) { 63 if( phase->eqv(in(1)->in(2),in(2)) ) 64 return in(1)->in(1); 65 if (phase->eqv(in(1)->in(1),in(2))) 66 return in(1)->in(2); 67 68 // Also catch: "(X + Opaque2(Y)) - Y". In this case, 'Y' is a loop-varying 69 // trip counter and X is likely to be loop-invariant (that's how O2 Nodes 70 // are originally used, although the optimizer sometimes jiggers things). 71 // This folding through an O2 removes a loop-exit use of a loop-varying 72 // value and generally lowers register pressure in and around the loop. 73 if( in(1)->in(2)->Opcode() == Opcodes::Op_Opaque2 && 74 phase->eqv(in(1)->in(2)->in(1),in(2)) ) 75 return in(1)->in(1); 76 } 77 78 return ( phase->type( in(2) )->higher_equal( zero ) ) ? in(1) : this; 79 } 80 81 //------------------------------Value------------------------------------------ 82 // A subtract node differences it's two inputs. 83 const Type* SubNode::Value_common(PhaseTransform *phase) const { 84 const Node* in1 = in(1); 85 const Node* in2 = in(2); 86 // Either input is TOP ==> the result is TOP 87 const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1); 88 if( t1 == Type::TOP ) return Type::TOP; 89 const Type* t2 = (in2 == this) ? Type::TOP : phase->type(in2); 90 if( t2 == Type::TOP ) return Type::TOP; 91 92 // Not correct for SubFnode and AddFNode (must check for infinity) 93 // Equal? Subtract is zero `````` 124 const PhiNode *phi; 125 if( ( !inc->in(1)->is_Phi() || 126 !(phi=inc->in(1)->as_Phi()) || 127 phi->is_copy() || 128 !phi->region()->is_CountedLoop() || 129 inc != phi->region()->as_CountedLoop()->incr() ) 130 && 131 // Do not collapse (x+c0)-iv if "iv" is a loop induction variable, 132 // because "x" maybe invariant. 133 ( !iv->is_loop_iv() ) 134 ) { 135 return true; 136 } else { 137 return false; 138 } 139 } 140 //------------------------------Ideal------------------------------------------ 141 Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){ 142 Node *in1 = in(1); 143 Node *in2 = in(2); 144 Opcodes op1 = in1->Opcode(); 145 Opcodes op2 = in2->Opcode(); 146 147 #ifdef ASSERT 148 // Check for dead loop 149 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 150 ( op1 == Opcodes::Op_AddI || op1 == Opcodes::Op_SubI ) && 151 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 152 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 153 assert(false, "dead loop in SubINode::Ideal"); 154 #endif 155 156 const Type *t2 = phase->type( in2 ); 157 if( t2 == Type::TOP ) return NULL; 158 // Convert "x-c0" into "x+ -c0". 159 if( t2->base() == Type::Int ){ // Might be bottom or top... 160 const TypeInt *i = t2->is_int(); 161 if( i->is_con() ) 162 return new AddINode(in1, phase->intcon(-i->get_con())); 163 } 164 165 // Convert "(x+c0) - y" into (x-y) + c0" 166 // Do not collapse (x+c0)-y if "+" is a loop increment or 167 // if "y" is a loop induction variable. 168 if( op1 == Opcodes::Op_AddI && ok_to_convert(in1, in2) ) { 169 const Type *tadd = phase->type( in1->in(2) ); 170 if( tadd->singleton() && tadd != Type::TOP ) { 171 Node *sub2 = phase->transform( new SubINode( in1->in(1), in2 )); 172 return new AddINode( sub2, in1->in(2) ); 173 } 174 } 175 176 177 // Convert "x - (y+c0)" into "(x-y) - c0" 178 // Need the same check as in above optimization but reversed. 179 if (op2 == Opcodes::Op_AddI && ok_to_convert(in2, in1)) { 180 Node* in21 = in2->in(1); 181 Node* in22 = in2->in(2); 182 const TypeInt* tcon = phase->type(in22)->isa_int(); 183 if (tcon != NULL && tcon->is_con()) { 184 Node* sub2 = phase->transform( new SubINode(in1, in21) ); 185 Node* neg_c0 = phase->intcon(- tcon->get_con()); 186 return new AddINode(sub2, neg_c0); 187 } 188 } 189 190 const Type *t1 = phase->type( in1 ); 191 if( t1 == Type::TOP ) return NULL; 192 193 #ifdef ASSERT 194 // Check for dead loop 195 if( ( op2 == Opcodes::Op_AddI || op2 == Opcodes::Op_SubI ) && 196 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 197 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 198 assert(false, "dead loop in SubINode::Ideal"); 199 #endif 200 201 // Convert "x - (x+y)" into "-y" 202 if( op2 == Opcodes::Op_AddI && 203 phase->eqv( in1, in2->in(1) ) ) 204 return new SubINode( phase->intcon(0),in2->in(2)); 205 // Convert "(x-y) - x" into "-y" 206 if( op1 == Opcodes::Op_SubI && 207 phase->eqv( in1->in(1), in2 ) ) 208 return new SubINode( phase->intcon(0),in1->in(2)); 209 // Convert "x - (y+x)" into "-y" 210 if( op2 == Opcodes::Op_AddI && 211 phase->eqv( in1, in2->in(2) ) ) 212 return new SubINode( phase->intcon(0),in2->in(1)); 213 214 // Convert "0 - (x-y)" into "y-x" 215 if( t1 == TypeInt::ZERO && op2 == Opcodes::Op_SubI ) 216 return new SubINode( in2->in(2), in2->in(1) ); 217 218 // Convert "0 - (x+con)" into "-con-x" 219 jint con; 220 if( t1 == TypeInt::ZERO && op2 == Opcodes::Op_AddI && 221 (con = in2->in(2)->find_int_con(0)) != 0 ) 222 return new SubINode( phase->intcon(-con), in2->in(1) ); 223 224 // Convert "(X+A) - (X+B)" into "A - B" 225 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(1) == in2->in(1) ) 226 return new SubINode( in1->in(2), in2->in(2) ); 227 228 // Convert "(A+X) - (B+X)" into "A - B" 229 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(2) ) 230 return new SubINode( in1->in(1), in2->in(1) ); 231 232 // Convert "(A+X) - (X+B)" into "A - B" 233 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(2) == in2->in(1) ) 234 return new SubINode( in1->in(1), in2->in(2) ); 235 236 // Convert "(X+A) - (B+X)" into "A - B" 237 if( op1 == Opcodes::Op_AddI && op2 == Opcodes::Op_AddI && in1->in(1) == in2->in(2) ) 238 return new SubINode( in1->in(2), in2->in(1) ); 239 240 // Convert "A-(B-C)" into (A+C)-B", since add is commutative and generally 241 // nicer to optimize than subtract. 242 if( op2 == Opcodes::Op_SubI && in2->outcnt() == 1) { 243 Node *add1 = phase->transform( new AddINode( in1, in2->in(2) ) ); 244 return new SubINode( add1, in2->in(1) ); 245 } 246 247 return NULL; 248 } 249 250 //------------------------------sub-------------------------------------------- 251 // A subtract node differences it's two inputs. 252 const Type *SubINode::sub( const Type *t1, const Type *t2 ) const { 253 const TypeInt *r0 = t1->is_int(); // Handy access 254 const TypeInt *r1 = t2->is_int(); 255 int32_t lo = java_subtract(r0->_lo, r1->_hi); 256 int32_t hi = java_subtract(r0->_hi, r1->_lo); 257 258 // We next check for 32-bit overflow. 259 // If that happens, we just assume all integers are possible. 260 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 261 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 262 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR 263 ((r0->_hi ^ hi) >= 0)) ) // hi results have same signs 264 return TypeInt::make(lo,hi,MAX2(r0->_widen,r1->_widen)); 265 else // Overflow; assume all integers 266 return TypeInt::INT; 267 } 268 269 //============================================================================= 270 //------------------------------Ideal------------------------------------------ 271 Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) { 272 Node *in1 = in(1); 273 Node *in2 = in(2); 274 Opcodes op1 = in1->Opcode(); 275 Opcodes op2 = in2->Opcode(); 276 277 #ifdef ASSERT 278 // Check for dead loop 279 if( phase->eqv( in1, this ) || phase->eqv( in2, this ) || 280 ( op1 == Opcodes::Op_AddL || op1 == Opcodes::Op_SubL ) && 281 ( phase->eqv( in1->in(1), this ) || phase->eqv( in1->in(2), this ) || 282 phase->eqv( in1->in(1), in1 ) || phase->eqv( in1->in(2), in1 ) ) ) 283 assert(false, "dead loop in SubLNode::Ideal"); 284 #endif 285 286 if( phase->type( in2 ) == Type::TOP ) return NULL; 287 const TypeLong *i = phase->type( in2 )->isa_long(); 288 // Convert "x-c0" into "x+ -c0". 289 if( i && // Might be bottom or top... 290 i->is_con() ) 291 return new AddLNode(in1, phase->longcon(-i->get_con())); 292 293 // Convert "(x+c0) - y" into (x-y) + c0" 294 // Do not collapse (x+c0)-y if "+" is a loop increment or 295 // if "y" is a loop induction variable. 296 if( op1 == Opcodes::Op_AddL && ok_to_convert(in1, in2) ) { 297 Node *in11 = in1->in(1); 298 const Type *tadd = phase->type( in1->in(2) ); 299 if( tadd->singleton() && tadd != Type::TOP ) { 300 Node *sub2 = phase->transform( new SubLNode( in11, in2 )); 301 return new AddLNode( sub2, in1->in(2) ); 302 } 303 } 304 305 // Convert "x - (y+c0)" into "(x-y) - c0" 306 // Need the same check as in above optimization but reversed. 307 if (op2 == Opcodes::Op_AddL && ok_to_convert(in2, in1)) { 308 Node* in21 = in2->in(1); 309 Node* in22 = in2->in(2); 310 const TypeLong* tcon = phase->type(in22)->isa_long(); 311 if (tcon != NULL && tcon->is_con()) { 312 Node* sub2 = phase->transform( new SubLNode(in1, in21) ); 313 Node* neg_c0 = phase->longcon(- tcon->get_con()); 314 return new AddLNode(sub2, neg_c0); 315 } 316 } 317 318 const Type *t1 = phase->type( in1 ); 319 if( t1 == Type::TOP ) return NULL; 320 321 #ifdef ASSERT 322 // Check for dead loop 323 if( ( op2 == Opcodes::Op_AddL || op2 == Opcodes::Op_SubL ) && 324 ( phase->eqv( in2->in(1), this ) || phase->eqv( in2->in(2), this ) || 325 phase->eqv( in2->in(1), in2 ) || phase->eqv( in2->in(2), in2 ) ) ) 326 assert(false, "dead loop in SubLNode::Ideal"); 327 #endif 328 329 // Convert "x - (x+y)" into "-y" 330 if( op2 == Opcodes::Op_AddL && 331 phase->eqv( in1, in2->in(1) ) ) 332 return new SubLNode( phase->makecon(TypeLong::ZERO), in2->in(2)); 333 // Convert "x - (y+x)" into "-y" 334 if( op2 == Opcodes::Op_AddL && 335 phase->eqv( in1, in2->in(2) ) ) 336 return new SubLNode( phase->makecon(TypeLong::ZERO),in2->in(1)); 337 338 // Convert "0 - (x-y)" into "y-x" 339 if( phase->type( in1 ) == TypeLong::ZERO && op2 == Opcodes::Op_SubL ) 340 return new SubLNode( in2->in(2), in2->in(1) ); 341 342 // Convert "(X+A) - (X+B)" into "A - B" 343 if( op1 == Opcodes::Op_AddL && op2 == Opcodes::Op_AddL && in1->in(1) == in2->in(1) ) 344 return new SubLNode( in1->in(2), in2->in(2) ); 345 346 // Convert "(A+X) - (B+X)" into "A - B" 347 if( op1 == Opcodes::Op_AddL && op2 == Opcodes::Op_AddL && in1->in(2) == in2->in(2) ) 348 return new SubLNode( in1->in(1), in2->in(1) ); 349 350 // Convert "A-(B-C)" into (A+C)-B" 351 if( op2 == Opcodes::Op_SubL && in2->outcnt() == 1) { 352 Node *add1 = phase->transform( new AddLNode( in1, in2->in(2) ) ); 353 return new SubLNode( add1, in2->in(1) ); 354 } 355 356 return NULL; 357 } 358 359 //------------------------------sub-------------------------------------------- 360 // A subtract node differences it's two inputs. 361 const Type *SubLNode::sub( const Type *t1, const Type *t2 ) const { 362 const TypeLong *r0 = t1->is_long(); // Handy access 363 const TypeLong *r1 = t2->is_long(); 364 jlong lo = java_subtract(r0->_lo, r1->_hi); 365 jlong hi = java_subtract(r0->_hi, r1->_lo); 366 367 // We next check for 32-bit overflow. 368 // If that happens, we just assume all integers are possible. 369 if( (((r0->_lo ^ r1->_hi) >= 0) || // lo ends have same signs OR 370 ((r0->_lo ^ lo) >= 0)) && // lo results have same signs AND 371 (((r0->_hi ^ r1->_lo) >= 0) || // hi ends have same signs OR `````` 611 // (This is a gross hack, since the sub method never 612 // looks at the structure of the node in any other case.) 613 if ((jint)lo0 >= 0 && (jint)lo1 >= 0 && is_index_range_check()) 614 return TypeInt::CC_LT; 615 return TypeInt::CC; // else use worst case results 616 } 617 618 const Type* CmpUNode::Value(PhaseGVN* phase) const { 619 const Type* t = SubNode::Value_common(phase); 620 if (t != NULL) { 621 return t; 622 } 623 const Node* in1 = in(1); 624 const Node* in2 = in(2); 625 const Type* t1 = phase->type(in1); 626 const Type* t2 = phase->type(in2); 627 assert(t1->isa_int(), "CmpU has only Int type inputs"); 628 if (t2 == TypeInt::INT) { // Compare to bottom? 629 return bottom_type(); 630 } 631 Opcodes in1_op = in1->Opcode(); 632 if (in1_op == Opcodes::Op_AddI || in1_op == Opcodes::Op_SubI) { 633 // The problem rise when result of AddI(SubI) may overflow 634 // signed integer value. Let say the input type is 635 // [256, maxint] then +128 will create 2 ranges due to 636 // overflow: [minint, minint+127] and [384, maxint]. 637 // But C2 type system keep only 1 type range and as result 638 // it use general [minint, maxint] for this case which we 639 // can't optimize. 640 // 641 // Make 2 separate type ranges based on types of AddI(SubI) inputs 642 // and compare results of their compare. If results are the same 643 // CmpU node can be optimized. 644 const Node* in11 = in1->in(1); 645 const Node* in12 = in1->in(2); 646 const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11); 647 const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12); 648 // Skip cases when input types are top or bottom. 649 if ((t11 != Type::TOP) && (t11 != TypeInt::INT) && 650 (t12 != Type::TOP) && (t12 != TypeInt::INT)) { 651 const TypeInt *r0 = t11->is_int(); 652 const TypeInt *r1 = t12->is_int(); 653 jlong lo_r0 = r0->_lo; 654 jlong hi_r0 = r0->_hi; 655 jlong lo_r1 = r1->_lo; 656 jlong hi_r1 = r1->_hi; 657 if (in1_op == Opcodes::Op_SubI) { 658 jlong tmp = hi_r1; 659 hi_r1 = -lo_r1; 660 lo_r1 = -tmp; 661 // Note, for substructing [minint,x] type range 662 // long arithmetic provides correct overflow answer. 663 // The confusion come from the fact that in 32-bit 664 // -minint == minint but in 64-bit -minint == maxint+1. 665 } 666 jlong lo_long = lo_r0 + lo_r1; 667 jlong hi_long = hi_r0 + hi_r1; 668 int lo_tr1 = min_jint; 669 int hi_tr1 = (int)hi_long; 670 int lo_tr2 = (int)lo_long; 671 int hi_tr2 = max_jint; 672 bool underflow = lo_long != (jlong)lo_tr2; 673 bool overflow = hi_long != (jlong)hi_tr1; 674 // Use sub(t1, t2) when there is no overflow (one type range) 675 // or when both overflow and underflow (too complex). 676 if ((underflow != overflow) && (hi_tr1 < lo_tr2)) { 677 // Overflow only on one boundary, compare 2 separate type ranges. 678 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 679 const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w); 680 const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w); 681 const Type* cmp1 = sub(tr1, t2); 682 const Type* cmp2 = sub(tr2, t2); 683 if (cmp1 == cmp2) { 684 return cmp1; // Hit! 685 } 686 } 687 } 688 } 689 690 return sub(t1, t2); // Local flavor of type subtraction 691 } 692 693 bool CmpUNode::is_index_range_check() const { 694 // Check for the "(X ModI Y) CmpU Y" shape 695 return (in(1)->Opcode() == Opcodes::Op_ModI && 696 in(1)->in(2)->eqv_uncast(in(2))); 697 } 698 699 //------------------------------Idealize--------------------------------------- 700 Node *CmpINode::Ideal( PhaseGVN *phase, bool can_reshape ) { 701 if (phase->type(in(2))->higher_equal(TypeInt::ZERO)) { 702 switch (in(1)->Opcode()) { 703 case Opcodes::Op_CmpL3: // Collapse a CmpL3/CmpI into a CmpL 704 return new CmpLNode(in(1)->in(1),in(1)->in(2)); 705 case Opcodes::Op_CmpF3: // Collapse a CmpF3/CmpI into a CmpF 706 return new CmpFNode(in(1)->in(1),in(1)->in(2)); 707 case Opcodes::Op_CmpD3: // Collapse a CmpD3/CmpI into a CmpD 708 return new CmpDNode(in(1)->in(1),in(1)->in(2)); 709 //case Op_SubI: 710 // If (x - y) cannot overflow, then ((x - y) 0) 711 // can be turned into (x y). 712 // This is handled (with more general cases) by Ideal_sub_algebra. 713 } 714 } 715 return NULL; // No change 716 } 717 718 719 //============================================================================= 720 // Simplify a CmpL (compare 2 longs ) node, based on local information. 721 // If both inputs are constants, compare them. 722 const Type *CmpLNode::sub( const Type *t1, const Type *t2 ) const { 723 const TypeLong *r0 = t1->is_long(); // Handy access 724 const TypeLong *r1 = t2->is_long(); 725 726 if( r0->_hi < r1->_lo ) // Range is always low? 727 return TypeInt::CC_LT; `````` 809 810 // Known constants can be compared exactly 811 // Null can be distinguished from any NotNull pointers 812 // Unknown inputs makes an unknown result 813 if( r0->singleton() ) { 814 intptr_t bits0 = r0->get_con(); 815 if( r1->singleton() ) 816 return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT; 817 return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC; 818 } else if( r1->singleton() ) { 819 intptr_t bits1 = r1->get_con(); 820 return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC; 821 } else 822 return TypeInt::CC; 823 } 824 825 static inline Node* isa_java_mirror_load(PhaseGVN* phase, Node* n) { 826 // Return the klass node for 827 // LoadP(AddP(foo:Klass, #java_mirror)) 828 // or NULL if not matching. 829 if (n->Opcode() != Opcodes::Op_LoadP) return NULL; 830 831 const TypeInstPtr* tp = phase->type(n)->isa_instptr(); 832 if (!tp || tp->klass() != phase->C->env()->Class_klass()) return NULL; 833 834 Node* adr = n->in(MemNode::Address); 835 intptr_t off = 0; 836 Node* k = AddPNode::Ideal_base_and_offset(adr, phase, off); 837 if (k == NULL) return NULL; 838 const TypeKlassPtr* tkp = phase->type(k)->isa_klassptr(); 839 if (!tkp || off != in_bytes(Klass::java_mirror_offset())) return NULL; 840 841 // We've found the klass node of a Java mirror load. 842 return k; 843 } 844 845 static inline Node* isa_const_java_mirror(PhaseGVN* phase, Node* n) { 846 // for ConP(Foo.class) return ConP(Foo.klass) 847 // otherwise return NULL 848 if (!n->is_Con()) return NULL; 849 `````` 894 if (k1 && (k2 || conk2)) { 895 Node* lhs = k1; 896 Node* rhs = (k2 != NULL) ? k2 : conk2; 897 this->set_req(1, lhs); 898 this->set_req(2, rhs); 899 return this; 900 } 901 } 902 903 // Constant pointer on right? 904 const TypeKlassPtr* t2 = phase->type(in(2))->isa_klassptr(); 905 if (t2 == NULL || !t2->klass_is_exact()) 906 return NULL; 907 // Get the constant klass we are comparing to. 908 ciKlass* superklass = t2->klass(); 909 910 // Now check for LoadKlass on left. 911 Node* ldk1 = in(1); 912 if (ldk1->is_DecodeNKlass()) { 913 ldk1 = ldk1->in(1); 914 if (ldk1->Opcode() != Opcodes::Op_LoadNKlass ) 915 return NULL; 916 } else if (ldk1->Opcode() != Opcodes::Op_LoadKlass ) 917 return NULL; 918 // Take apart the address of the LoadKlass: 919 Node* adr1 = ldk1->in(MemNode::Address); 920 intptr_t con2 = 0; 921 Node* ldk2 = AddPNode::Ideal_base_and_offset(adr1, phase, con2); 922 if (ldk2 == NULL) 923 return NULL; 924 if (con2 == oopDesc::klass_offset_in_bytes()) { 925 // We are inspecting an object's concrete class. 926 // Short-circuit the check if the query is abstract. 927 if (superklass->is_interface() || 928 superklass->is_abstract()) { 929 // Make it come out always false: 930 this->set_req(2, phase->makecon(TypePtr::NULL_PTR)); 931 return this; 932 } 933 } 934 935 // Check for a LoadKlass from primary supertype array. 936 // Any nested loadklass from loadklass+con must be from the p.s. array. 937 if (ldk2->is_DecodeNKlass()) { 938 // Keep ldk2 as DecodeN since it could be used in CmpP below. 939 if (ldk2->in(1)->Opcode() != Opcodes::Op_LoadNKlass ) 940 return NULL; 941 } else if (ldk2->Opcode() != Opcodes::Op_LoadKlass) 942 return NULL; 943 944 // Verify that we understand the situation 945 if (con2 != (intptr_t) superklass->super_check_offset()) 946 return NULL; // Might be element-klass loading from array klass 947 948 // If 'superklass' has no subklasses and is not an interface, then we are 949 // assured that the only input which will pass the type check is 950 // 'superklass' itself. 951 // 952 // We could be more liberal here, and allow the optimization on interfaces 953 // which have a single implementor. This would require us to increase the 954 // expressiveness of the add_dependency() mechanism. 955 // %%% Do this after we fix TypeOopPtr: Deps are expressive enough now. 956 957 // Object arrays must have their base element have no subtypes 958 while (superklass->is_obj_array_klass()) { 959 ciType* elem = superklass->as_obj_array_klass()->element_type(); 960 superklass = elem->as_klass(); 961 } ``````1106 if( td1->is_nan() || td2->is_nan() ) 1107 return TypeInt::CC_LT; 1108 1109 if( td1->_d < td2->_d ) return TypeInt::CC_LT; 1110 if( td1->_d > td2->_d ) return TypeInt::CC_GT; 1111 assert( td1->_d == td2->_d, "do not understand FP behavior" ); 1112 return TypeInt::CC_EQ; 1113 } 1114 1115 //------------------------------Ideal------------------------------------------ 1116 Node *CmpDNode::Ideal(PhaseGVN *phase, bool can_reshape){ 1117 // Check if we can change this to a CmpF and remove a ConvD2F operation. 1118 // Change (CMPD (F2D (float)) (ConD value)) 1119 // To (CMPF (float) (ConF value)) 1120 // Valid when 'value' does not lose precision as a float. 1121 // Benefits: eliminates conversion, does not require 24-bit mode 1122 1123 // NaNs prevent commuting operands. This transform works regardless of the 1124 // order of ConD and ConvF2D inputs by preserving the original order. 1125 int idx_f2d = 1; // ConvF2D on left side? 1126 if( in(idx_f2d)->Opcode() != Opcodes::Op_ConvF2D ) 1127 idx_f2d = 2; // No, swap to check for reversed args 1128 int idx_con = 3-idx_f2d; // Check for the constant on other input 1129 1130 if( ConvertCmpD2CmpF && 1131 in(idx_f2d)->Opcode() == Opcodes::Op_ConvF2D && 1132 in(idx_con)->Opcode() == Opcodes::Op_ConD ) { 1133 const TypeD *t2 = in(idx_con)->bottom_type()->is_double_constant(); 1134 double t2_value_as_double = t2->_d; 1135 float t2_value_as_float = (float)t2_value_as_double; 1136 if( t2_value_as_double == (double)t2_value_as_float ) { 1137 // Test value can be represented as a float 1138 // Eliminate the conversion to double and create new comparison 1139 Node *new_in1 = in(idx_f2d)->in(1); 1140 Node *new_in2 = phase->makecon( TypeF::make(t2_value_as_float) ); 1141 if( idx_f2d != 1 ) { // Must flip args to match original order 1142 Node *tmp = new_in1; 1143 new_in1 = new_in2; 1144 new_in2 = tmp; 1145 } 1146 CmpFNode *new_cmp = (Opcode() == Opcodes::Op_CmpD3) 1147 ? new CmpF3Node( new_in1, new_in2 ) 1148 : new CmpFNode ( new_in1, new_in2 ) ; 1149 return new_cmp; // Changed to CmpFNode 1150 } 1151 // Testing value required the precision of a double 1152 } 1153 return NULL; // No change 1154 } 1155 1156 1157 //============================================================================= 1158 //------------------------------cc2logical------------------------------------- 1159 // Convert a condition code type to a logical type 1160 const Type *BoolTest::cc2logical( const Type *CC ) const { 1161 if( CC == Type::TOP ) return Type::TOP; 1162 if( CC->base() != Type::Int ) return TypeInt::BOOL; // Bottom or worse 1163 const TypeInt *ti = CC->is_int(); 1164 if( ti->is_con() ) { // Only 1 kind of condition codes set? 1165 // Match low order 2 bits 1166 int tmp = ((ti->get_con()&3) == (_test&3)) ? 1 : 0; ``````1220 return phase->transform(bol); 1221 } 1222 1223 //--------------------------------as_int_value--------------------------------- 1224 Node* BoolNode::as_int_value(PhaseGVN* phase) { 1225 // Inverse to make_predicate. The CMove probably boils down to a Conv2B. 1226 Node* cmov = CMoveNode::make(NULL, this, 1227 phase->intcon(0), phase->intcon(1), 1228 TypeInt::BOOL); 1229 return phase->transform(cmov); 1230 } 1231 1232 //----------------------------------negate------------------------------------- 1233 BoolNode* BoolNode::negate(PhaseGVN* phase) { 1234 return new BoolNode(in(1), _test.negate()); 1235 } 1236 1237 // Change "bool eq/ne (cmp (add/sub A B) C)" into false/true if add/sub 1238 // overflows and we can prove that C is not in the two resulting ranges. 1239 // This optimization is similar to the one performed by CmpUNode::Value(). 1240 Node* BoolNode::fold_cmpI(PhaseGVN* phase, SubNode* cmp, Node* cmp1, Opcodes cmp_op, 1241 Opcodes cmp1_op, const TypeInt* cmp2_type) { 1242 // Only optimize eq/ne integer comparison of add/sub 1243 if((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1244 (cmp_op == Opcodes::Op_CmpI) && (cmp1_op == Opcodes::Op_AddI || cmp1_op == Opcodes::Op_SubI)) { 1245 // Skip cases were inputs of add/sub are not integers or of bottom type 1246 const TypeInt* r0 = phase->type(cmp1->in(1))->isa_int(); 1247 const TypeInt* r1 = phase->type(cmp1->in(2))->isa_int(); 1248 if ((r0 != NULL) && (r0 != TypeInt::INT) && 1249 (r1 != NULL) && (r1 != TypeInt::INT) && 1250 (cmp2_type != TypeInt::INT)) { 1251 // Compute exact (long) type range of add/sub result 1252 jlong lo_long = r0->_lo; 1253 jlong hi_long = r0->_hi; 1254 if (cmp1_op == Opcodes::Op_AddI) { 1255 lo_long += r1->_lo; 1256 hi_long += r1->_hi; 1257 } else { 1258 lo_long -= r1->_hi; 1259 hi_long -= r1->_lo; 1260 } 1261 // Check for over-/underflow by casting to integer 1262 int lo_int = (int)lo_long; 1263 int hi_int = (int)hi_long; 1264 bool underflow = lo_long != (jlong)lo_int; 1265 bool overflow = hi_long != (jlong)hi_int; 1266 if ((underflow != overflow) && (hi_int < lo_int)) { 1267 // Overflow on one boundary, compute resulting type ranges: 1268 // tr1 [MIN_INT, hi_int] and tr2 [lo_int, MAX_INT] 1269 int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here 1270 const TypeInt* tr1 = TypeInt::make(min_jint, hi_int, w); 1271 const TypeInt* tr2 = TypeInt::make(lo_int, max_jint, w); 1272 // Compare second input of cmp to both type ranges 1273 const Type* sub_tr1 = cmp->sub(tr1, cmp2_type); 1274 const Type* sub_tr2 = cmp->sub(tr2, cmp2_type); 1275 if (sub_tr1 == TypeInt::CC_LT && sub_tr2 == TypeInt::CC_GT) { 1276 // The result of the add/sub will never equal cmp2. Replace BoolNode 1277 // by false (0) if it tests for equality and by true (1) otherwise. 1278 return ConINode::make((_test._test == BoolTest::eq) ? 0 : 1); 1279 } 1280 } 1281 } 1282 } 1283 return NULL; 1284 } 1285 1286 //------------------------------Ideal------------------------------------------ 1287 Node *BoolNode::Ideal(PhaseGVN *phase, bool can_reshape) { 1288 // Change "bool tst (cmp con x)" into "bool ~tst (cmp x con)". 1289 // This moves the constant to the right. Helps value-numbering. 1290 Node *cmp = in(1); 1291 if( !cmp->is_Sub() ) return NULL; 1292 Opcodes cop = cmp->Opcode(); 1293 if( cop == Opcodes::Op_FastLock || cop == Opcodes::Op_FastUnlock) return NULL; 1294 Node *cmp1 = cmp->in(1); 1295 Node *cmp2 = cmp->in(2); 1296 if( !cmp1 ) return NULL; 1297 1298 if (_test._test == BoolTest::overflow || _test._test == BoolTest::no_overflow) { 1299 return NULL; 1300 } 1301 1302 // Constant on left? 1303 Node *con = cmp1; 1304 Opcodes op2 = cmp2->Opcode(); 1305 // Move constants to the right of compare's to canonicalize. 1306 // Do not muck with Opaque1 nodes, as this indicates a loop 1307 // guard that cannot change shape. 1308 if( con->is_Con() && !cmp2->is_Con() && op2 != Opcodes::Op_Opaque1 && 1309 // Because of NaN's, CmpD and CmpF are not commutative 1310 cop != Opcodes::Op_CmpD && cop != Opcodes::Op_CmpF && 1311 // Protect against swapping inputs to a compare when it is used by a 1312 // counted loop exit, which requires maintaining the loop-limit as in(2) 1313 !is_counted_loop_exit_test() ) { 1314 // Ok, commute the constant to the right of the cmp node. 1315 // Clone the Node, getting a new Node of the same class 1316 cmp = cmp->clone(); 1317 // Swap inputs to the clone 1318 cmp->swap_edges(1, 2); 1319 cmp = phase->transform( cmp ); 1320 return new BoolNode( cmp, _test.commute() ); 1321 } 1322 1323 // Change "bool eq/ne (cmp (xor X 1) 0)" into "bool ne/eq (cmp X 0)". 1324 // The XOR-1 is an idiom used to flip the sense of a bool. We flip the 1325 // test instead. 1326 Opcodes cmp1_op = cmp1->Opcode(); 1327 const TypeInt* cmp2_type = phase->type(cmp2)->isa_int(); 1328 if (cmp2_type == NULL) return NULL; 1329 Node* j_xor = cmp1; 1330 if( cmp2_type == TypeInt::ZERO && 1331 cmp1_op == Opcodes::Op_XorI && 1332 j_xor->in(1) != j_xor && // An xor of itself is dead 1333 phase->type( j_xor->in(1) ) == TypeInt::BOOL && 1334 phase->type( j_xor->in(2) ) == TypeInt::ONE && 1335 (_test._test == BoolTest::eq || 1336 _test._test == BoolTest::ne) ) { 1337 Node *ncmp = phase->transform(new CmpINode(j_xor->in(1),cmp2)); 1338 return new BoolNode( ncmp, _test.negate() ); 1339 } 1340 1341 // Change ((x & m) u<= m) or ((m & x) u<= m) to always true 1342 // Same with ((x & m) u< m+1) and ((m & x) u< m+1) 1343 if (cop == Opcodes::Op_CmpU && 1344 cmp1->Opcode() == Opcodes::Op_AndI) { 1345 Node* bound = NULL; 1346 if (_test._test == BoolTest::le) { 1347 bound = cmp2; 1348 } else if (_test._test == BoolTest::lt && 1349 cmp2->Opcode() == Opcodes::Op_AddI && 1350 cmp2->in(2)->find_int_con(0) == 1) { 1351 bound = cmp2->in(1); 1352 } 1353 if (cmp1->in(2) == bound || cmp1->in(1) == bound) { 1354 return ConINode::make(1); 1355 } 1356 } 1357 1358 // Change ((x & (m - 1)) u< m) into (m > 0) 1359 // This is the off-by-one variant of the above 1360 if (cop == Opcodes::Op_CmpU && 1361 _test._test == BoolTest::lt && 1362 cmp1->Opcode() == Opcodes::Op_AndI) { 1363 Node* l = cmp1->in(1); 1364 Node* r = cmp1->in(2); 1365 for (int repeat = 0; repeat < 2; repeat++) { 1366 bool match = r->Opcode() == Opcodes::Op_AddI && r->in(2)->find_int_con(0) == -1 && 1367 r->in(1) == cmp2; 1368 if (match) { 1369 // arraylength known to be non-negative, so a (arraylength != 0) is sufficient, 1370 // but to be compatible with the array range check pattern, use (arraylength u> 0) 1371 Node* ncmp = cmp2->Opcode() == Opcodes::Op_LoadRange 1372 ? phase->transform(new CmpUNode(cmp2, phase->intcon(0))) 1373 : phase->transform(new CmpINode(cmp2, phase->intcon(0))); 1374 return new BoolNode(ncmp, BoolTest::gt); 1375 } else { 1376 // commute and try again 1377 l = cmp1->in(2); 1378 r = cmp1->in(1); 1379 } 1380 } 1381 } 1382 1383 // Change (arraylength <= 0) or (arraylength == 0) 1384 // into (arraylength u<= 0) 1385 // Also change (arraylength != 0) into (arraylength u> 0) 1386 // The latter version matches the code pattern generated for 1387 // array range checks, which will more likely be optimized later. 1388 if (cop == Opcodes::Op_CmpI && 1389 cmp1->Opcode() == Opcodes::Op_LoadRange && 1390 cmp2->find_int_con(-1) == 0) { 1391 if (_test._test == BoolTest::le || _test._test == BoolTest::eq) { 1392 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1393 return new BoolNode(ncmp, BoolTest::le); 1394 } else if (_test._test == BoolTest::ne) { 1395 Node* ncmp = phase->transform(new CmpUNode(cmp1, cmp2)); 1396 return new BoolNode(ncmp, BoolTest::gt); 1397 } 1398 } 1399 1400 // Change "bool eq/ne (cmp (Conv2B X) 0)" into "bool eq/ne (cmp X 0)". 1401 // This is a standard idiom for branching on a boolean value. 1402 Node *c2b = cmp1; 1403 if( cmp2_type == TypeInt::ZERO && 1404 cmp1_op == Opcodes::Op_Conv2B && 1405 (_test._test == BoolTest::eq || 1406 _test._test == BoolTest::ne) ) { 1407 Node *ncmp = phase->transform(phase->type(c2b->in(1))->isa_int() 1408 ? (Node*)new CmpINode(c2b->in(1),cmp2) 1409 : (Node*)new CmpPNode(c2b->in(1),phase->makecon(TypePtr::NULL_PTR)) 1410 ); 1411 return new BoolNode( ncmp, _test._test ); 1412 } 1413 1414 // Comparing a SubI against a zero is equal to comparing the SubI 1415 // arguments directly. This only works for eq and ne comparisons 1416 // due to possible integer overflow. 1417 if ((_test._test == BoolTest::eq || _test._test == BoolTest::ne) && 1418 (cop == Opcodes::Op_CmpI) && 1419 (cmp1->Opcode() == Opcodes::Op_SubI) && 1420 ( cmp2_type == TypeInt::ZERO ) ) { 1421 Node *ncmp = phase->transform( new CmpINode(cmp1->in(1),cmp1->in(2))); 1422 return new BoolNode( ncmp, _test._test ); 1423 } 1424 1425 // Change (-A vs 0) into (A vs 0) by commuting the test. Disallow in the 1426 // most general case because negating 0x80000000 does nothing. Needed for 1427 // the CmpF3/SubI/CmpI idiom. 1428 if( cop == Opcodes::Op_CmpI && 1429 cmp1->Opcode() == Opcodes::Op_SubI && 1430 cmp2_type == TypeInt::ZERO && 1431 phase->type( cmp1->in(1) ) == TypeInt::ZERO && 1432 phase->type( cmp1->in(2) )->higher_equal(TypeInt::SYMINT) ) { 1433 Node *ncmp = phase->transform( new CmpINode(cmp1->in(2),cmp2)); 1434 return new BoolNode( ncmp, _test.commute() ); 1435 } 1436 1437 // Try to optimize signed integer comparison 1438 return fold_cmpI(phase, cmp->as_Sub(), cmp1, cop, cmp1_op, cmp2_type); 1439 1440 // The transformation below is not valid for either signed or unsigned 1441 // comparisons due to wraparound concerns at MAX_VALUE and MIN_VALUE. 1442 // This transformation can be resurrected when we are able to 1443 // make inferences about the range of values being subtracted from 1444 // (or added to) relative to the wraparound point. 1445 // 1446 // // Remove +/-1's if possible. 1447 // // "X <= Y-1" becomes "X < Y" 1448 // // "X+1 <= Y" becomes "X < Y" 1449 // // "X < Y+1" becomes "X <= Y" ```