graal-compiler: src/share/vm/opto/gcm.cpp comparison

6611837: block frequency is zero Summary: insert_goto_at should set frequency for newly created blocks Reviewed-by: never

comparison

equal deleted inserted replaced

-:892493c3d862
+:756b58154237
 //------------------------------succ_prob-------------------------------------
 // Determine the probability of reaching successor 'i' from the receiver block.
 float Block::succ_prob(uint i) {
 int eidx = end_idx();
 Node *n = _nodes[eidx];  // Get ending Node
-int op = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : n->Opcode();
+int op = n->Opcode();
+if (n->is_Mach()) {
+if (n->is_MachNullCheck()) {
+// Can only reach here if called after lcm. The original Op_If is gone,
+// so we attempt to infer the probability from one or both of the
+// successor blocks.
+assert(_num_succs == 2, "expecting 2 successors of a null check");
+// If either successor has only one predecessor, then the
+// probabiltity estimate can be derived using the
+// relative frequency of the successor and this block.
+if (_succs[i]->num_preds() == 2) {
+return _succs[i]->_freq / _freq;
+} else if (_succs[1-i]->num_preds() == 2) {
+return 1 - (_succs[1-i]->_freq / _freq);
+} else {
+// Estimate using both successor frequencies
+float freq = _succs[i]->_freq;
+return freq / (freq + _succs[1-i]->_freq);
+}
+}
+op = n->as_Mach()->ideal_Opcode();
+}
 // Switch on branch type
 switch( op ) {
 case Op_CountedLoopEnd:
 case Op_If: {

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