102 Node *CMoveNode::Ideal(PhaseGVN *phase, bool can_reshape) {
103 if( in(0) && remove_dead_region(phase, can_reshape) ) return this;
104 // Don't bother trying to transform a dead node
105 if( in(0) && in(0)->is_top() ) return NULL;
106 assert( !phase->eqv(in(Condition), this) &&
107 !phase->eqv(in(IfFalse), this) &&
108 !phase->eqv(in(IfTrue), this), "dead loop in CMoveNode::Ideal" );
109 if( phase->type(in(Condition)) == Type::TOP )
110 return NULL; // return NULL when Condition is dead
111
112 if( in(IfFalse)->is_Con() && !in(IfTrue)->is_Con() ) {
113 if( in(Condition)->is_Bool() ) {
114 BoolNode* b = in(Condition)->as_Bool();
115 BoolNode* b2 = b->negate(phase);
116 return make( phase->C, in(Control), phase->transform(b2), in(IfTrue), in(IfFalse), _type );
117 }
118 }
119 return NULL;
120 }
121
122 //------------------------------is_cmove_id------------------------------------
123 // Helper function to check for CMOVE identity. Shared with PhiNode::Identity
124 Node *CMoveNode::is_cmove_id( PhaseTransform *phase, Node *cmp, Node *t, Node *f, BoolNode *b ) {
125 // Check for Cmp'ing and CMove'ing same values
126 if( (phase->eqv(cmp->in(1),f) &&
127 phase->eqv(cmp->in(2),t)) ||
128 // Swapped Cmp is OK
129 (phase->eqv(cmp->in(2),f) &&
130 phase->eqv(cmp->in(1),t)) ) {
131 // Check for "(t==f)?t:f;" and replace with "f"
132 if( b->_test._test == BoolTest::eq )
133 return f;
134 // Allow the inverted case as well
135 // Check for "(t!=f)?t:f;" and replace with "t"
136 if( b->_test._test == BoolTest::ne )
137 return t;
138 }
139 return NULL;
140 }
141
142 //------------------------------Identity---------------------------------------
143 // Conditional-move is an identity if both inputs are the same, or the test
144 // true or false.
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102 Node *CMoveNode::Ideal(PhaseGVN *phase, bool can_reshape) {
103 if( in(0) && remove_dead_region(phase, can_reshape) ) return this;
104 // Don't bother trying to transform a dead node
105 if( in(0) && in(0)->is_top() ) return NULL;
106 assert( !phase->eqv(in(Condition), this) &&
107 !phase->eqv(in(IfFalse), this) &&
108 !phase->eqv(in(IfTrue), this), "dead loop in CMoveNode::Ideal" );
109 if( phase->type(in(Condition)) == Type::TOP )
110 return NULL; // return NULL when Condition is dead
111
112 if( in(IfFalse)->is_Con() && !in(IfTrue)->is_Con() ) {
113 if( in(Condition)->is_Bool() ) {
114 BoolNode* b = in(Condition)->as_Bool();
115 BoolNode* b2 = b->negate(phase);
116 return make( phase->C, in(Control), phase->transform(b2), in(IfTrue), in(IfFalse), _type );
117 }
118 }
119 return NULL;
120 }
121
122 //-----------------------------is_float_or_double_zero-----------------------
123 // Helper function for is_cmove_id to find float or double constant 0.0
124 bool CMoveNode::is_float_or_double_zero(PhaseTransform* phase, Node *val) {
125 const Type* t = phase->type(val);
126 if (t == Type::TOP) return false;
127 const TypeF *tf = t->isa_float_constant();
128 if( tf != NULL && tf->_f==0.0)
129 return true;
130 const TypeD *td = t->isa_double_constant();
131 if( td != NULL && td->_d==0.0)
132 return true;
133
134 return false;
135 }
136
137 //------------------------------is_cmove_id------------------------------------
138 // Helper function to check for CMOVE identity. Shared with PhiNode::Identity
139 Node *CMoveNode::is_cmove_id( PhaseTransform *phase, Node *cmp, Node *t, Node *f, BoolNode *b ) {
140 // Give up this identity check if either "t" or "f" is 0.0 (or -0.0)
141 // For example, for (f==0.0)?0.0:f, and if f = -0.0, the result should be 0.0 instead of -0.0(f)
142 // NOTE: non-constant double or float may still turn out to be 0.0 (-0.0). However, it may be
143 // too expensive to disable this optimization for general cases.
144 if( is_float_or_double_zero(phase, t) ||
145 is_float_or_double_zero(phase, f) )
146 return NULL;
147
148 // Check for Cmp'ing and CMove'ing same values
149 if( (phase->eqv(cmp->in(1),f) &&
150 phase->eqv(cmp->in(2),t)) ||
151 // Swapped Cmp is OK
152 (phase->eqv(cmp->in(2),f) &&
153 phase->eqv(cmp->in(1),t)) ) {
154 // Check for "(t==f)?t:f;" and replace with "f"
155 if( b->_test._test == BoolTest::eq )
156 return f;
157 // Allow the inverted case as well
158 // Check for "(t!=f)?t:f;" and replace with "t"
159 if( b->_test._test == BoolTest::ne )
160 return t;
161 }
162 return NULL;
163 }
164
165 //------------------------------Identity---------------------------------------
166 // Conditional-move is an identity if both inputs are the same, or the test
167 // true or false.
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