--- old/src/share/vm/opto/subnode.cpp 2014-05-15 13:39:48.000000000 -0700 +++ new/src/share/vm/opto/subnode.cpp 2014-05-15 13:39:48.000000000 -0700 @@ -80,7 +80,7 @@ //------------------------------Value------------------------------------------ // A subtract node differences it's two inputs. -const Type *SubNode::Value( PhaseTransform *phase ) const { +const Type* SubNode::Value_common(PhaseTransform *phase) const { const Node* in1 = in(1); const Node* in2 = in(2); // Either input is TOP ==> the result is TOP @@ -97,6 +97,16 @@ if( t1 == Type::BOTTOM || t2 == Type::BOTTOM ) return bottom_type(); + return NULL; +} + +const Type* SubNode::Value(PhaseTransform *phase) const { + const Type* t = Value_common(phase); + if (t != NULL) { + return t; + } + const Type* t1 = phase->type(in(1)); + const Type* t2 = phase->type(in(2)); return sub(t1,t2); // Local flavor of type subtraction } @@ -570,6 +580,81 @@ return TypeInt::CC; // else use worst case results } +const Type* CmpUNode::Value(PhaseTransform *phase) const { + const Type* t = SubNode::Value_common(phase); + if (t != NULL) { + return t; + } + const Node* in1 = in(1); + const Node* in2 = in(2); + const Type* t1 = phase->type(in1); + const Type* t2 = phase->type(in2); + assert(t1->isa_int(), "CmpU has only Int type inputs"); + if (t2 == TypeInt::INT) { // Compare to bottom? + return bottom_type(); + } + uint in1_op = in1->Opcode(); + if (in1_op == Op_AddI || in1_op == Op_SubI) { + // The problem rise when result of AddI(SubI) may overflow + // signed integer value. Let say the input type is + // [256, maxint] then +128 will create 2 ranges due to + // overflow: [minint, minint+127] and [384, maxint]. + // But C2 type system keep only 1 type range and as result + // it use general [minint, maxint] for this case which we + // can't optimize. + // + // Make 2 separate type ranges based on types of AddI(SubI) inputs + // and compare results of their compare. If results are the same + // CmpU node can be optimized. + const Node* in11 = in1->in(1); + const Node* in12 = in1->in(2); + const Type* t11 = (in11 == in1) ? Type::TOP : phase->type(in11); + const Type* t12 = (in12 == in1) ? Type::TOP : phase->type(in12); + // Skip cases when input types are top or bottom. + if ((t11 != Type::TOP) && (t11 != TypeInt::INT) && + (t12 != Type::TOP) && (t12 != TypeInt::INT)) { + const TypeInt *r0 = t11->is_int(); + const TypeInt *r1 = t12->is_int(); + jlong lo_r0 = r0->_lo; + jlong hi_r0 = r0->_hi; + jlong lo_r1 = r1->_lo; + jlong hi_r1 = r1->_hi; + if (in1_op == Op_SubI) { + jlong tmp = hi_r1; + hi_r1 = -lo_r1; + lo_r1 = -tmp; + // Note, for substructing [minint,x] type range + // long arithmetic provides correct overflow answer. + // The confusion come from the fact that in 32-bit + // -minint == minint but in 64-bit -minint == maxint+1. + } + jlong lo_long = lo_r0 + lo_r1; + jlong hi_long = hi_r0 + hi_r1; + int lo_tr1 = min_jint; + int hi_tr1 = (int)hi_long; + int lo_tr2 = (int)lo_long; + int hi_tr2 = max_jint; + bool underflow = lo_long != (jlong)lo_tr2; + bool overflow = hi_long != (jlong)hi_tr1; + // Use sub(t1, t2) when there is no overflow (one type range) + // or when both overflow and underflow (too complex). + if ((underflow != overflow) && (hi_tr1 < lo_tr2)) { + // Overflow only on one boundary, compare 2 separate type ranges. + int w = MAX2(r0->_widen, r1->_widen); // _widen does not matter here + const TypeInt* tr1 = TypeInt::make(lo_tr1, hi_tr1, w); + const TypeInt* tr2 = TypeInt::make(lo_tr2, hi_tr2, w); + const Type* cmp1 = sub(tr1, t2); + const Type* cmp2 = sub(tr2, t2); + if (cmp1 == cmp2) { + return cmp1; // Hit! + } + } + } + } + + return sub(t1, t2); // Local flavor of type subtraction +} + bool CmpUNode::is_index_range_check() const { // Check for the "(X ModI Y) CmpU Y" shape return (in(1)->Opcode() == Op_ModI &&