1.1 --- a/src/share/vm/opto/subnode.cpp Fri Apr 11 09:56:35 2008 -0400
1.2 +++ b/src/share/vm/opto/subnode.cpp Sun Apr 13 17:43:42 2008 -0400
1.3 @@ -736,6 +736,75 @@
1.4 }
1.5
1.6 //=============================================================================
1.7 +//------------------------------sub--------------------------------------------
1.8 +// Simplify an CmpN (compare 2 pointers) node, based on local information.
1.9 +// If both inputs are constants, compare them.
1.10 +const Type *CmpNNode::sub( const Type *t1, const Type *t2 ) const {
1.11 + const TypePtr *r0 = t1->is_narrowoop()->make_oopptr(); // Handy access
1.12 + const TypePtr *r1 = t2->is_narrowoop()->make_oopptr();
1.13 +
1.14 + // Undefined inputs makes for an undefined result
1.15 + if( TypePtr::above_centerline(r0->_ptr) ||
1.16 + TypePtr::above_centerline(r1->_ptr) )
1.17 + return Type::TOP;
1.18 +
1.19 + if (r0 == r1 && r0->singleton()) {
1.20 + // Equal pointer constants (klasses, nulls, etc.)
1.21 + return TypeInt::CC_EQ;
1.22 + }
1.23 +
1.24 + // See if it is 2 unrelated classes.
1.25 + const TypeOopPtr* p0 = r0->isa_oopptr();
1.26 + const TypeOopPtr* p1 = r1->isa_oopptr();
1.27 + if (p0 && p1) {
1.28 + ciKlass* klass0 = p0->klass();
1.29 + bool xklass0 = p0->klass_is_exact();
1.30 + ciKlass* klass1 = p1->klass();
1.31 + bool xklass1 = p1->klass_is_exact();
1.32 + int kps = (p0->isa_klassptr()?1:0) + (p1->isa_klassptr()?1:0);
1.33 + if (klass0 && klass1 &&
1.34 + kps != 1 && // both or neither are klass pointers
1.35 + !klass0->is_interface() && // do not trust interfaces
1.36 + !klass1->is_interface()) {
1.37 + // See if neither subclasses the other, or if the class on top
1.38 + // is precise. In either of these cases, the compare must fail.
1.39 + if (klass0->equals(klass1) || // if types are unequal but klasses are
1.40 + !klass0->is_java_klass() || // types not part of Java language?
1.41 + !klass1->is_java_klass()) { // types not part of Java language?
1.42 + // Do nothing; we know nothing for imprecise types
1.43 + } else if (klass0->is_subtype_of(klass1)) {
1.44 + // If klass1's type is PRECISE, then we can fail.
1.45 + if (xklass1) return TypeInt::CC_GT;
1.46 + } else if (klass1->is_subtype_of(klass0)) {
1.47 + // If klass0's type is PRECISE, then we can fail.
1.48 + if (xklass0) return TypeInt::CC_GT;
1.49 + } else { // Neither subtypes the other
1.50 + return TypeInt::CC_GT; // ...so always fail
1.51 + }
1.52 + }
1.53 + }
1.54 +
1.55 + // Known constants can be compared exactly
1.56 + // Null can be distinguished from any NotNull pointers
1.57 + // Unknown inputs makes an unknown result
1.58 + if( r0->singleton() ) {
1.59 + intptr_t bits0 = r0->get_con();
1.60 + if( r1->singleton() )
1.61 + return bits0 == r1->get_con() ? TypeInt::CC_EQ : TypeInt::CC_GT;
1.62 + return ( r1->_ptr == TypePtr::NotNull && bits0==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1.63 + } else if( r1->singleton() ) {
1.64 + intptr_t bits1 = r1->get_con();
1.65 + return ( r0->_ptr == TypePtr::NotNull && bits1==0 ) ? TypeInt::CC_GT : TypeInt::CC;
1.66 + } else
1.67 + return TypeInt::CC;
1.68 +}
1.69 +
1.70 +//------------------------------Ideal------------------------------------------
1.71 +Node *CmpNNode::Ideal( PhaseGVN *phase, bool can_reshape ) {
1.72 + return NULL;
1.73 +}
1.74 +
1.75 +//=============================================================================
1.76 //------------------------------Value------------------------------------------
1.77 // Simplify an CmpF (compare 2 floats ) node, based on local information.
1.78 // If both inputs are constants, compare them.
