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src/share/vm/opto/subnode.cpp

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rev 9644 : 8145096: Undefined behaviour in HotSpot
Summary: Fix some integer overflows
Reviewed-by: duke


 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 = r0->_lo - r1->_hi;
 256   int32_t hi = 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 


 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 = r0->_lo - r1->_hi;
 365   jlong hi = 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
 372        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 373     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 374   else                          // Overflow; assume all integers
 375     return TypeLong::LONG;
 376 }
 377 
 378 //=============================================================================
 379 //------------------------------Value------------------------------------------
 380 // A subtract node differences its two inputs.
 381 const Type *SubFPNode::Value( PhaseTransform *phase ) const {
 382   const Node* in1 = in(1);
 383   const Node* in2 = in(2);
 384   // Either input is TOP ==> the result is TOP
 385   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);




 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 


 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
 372        ((r0->_hi ^      hi) >= 0)) )    // hi results have same signs
 373     return TypeLong::make(lo,hi,MAX2(r0->_widen,r1->_widen));
 374   else                          // Overflow; assume all integers
 375     return TypeLong::LONG;
 376 }
 377 
 378 //=============================================================================
 379 //------------------------------Value------------------------------------------
 380 // A subtract node differences its two inputs.
 381 const Type *SubFPNode::Value( PhaseTransform *phase ) const {
 382   const Node* in1 = in(1);
 383   const Node* in2 = in(2);
 384   // Either input is TOP ==> the result is TOP
 385   const Type* t1 = (in1 == this) ? Type::TOP : phase->type(in1);


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