638   if( !phi ) return n;
 639 
 640   // Found a Phi to split thru!
 641   // Replace 'n' with the new phi
 642   _igvn.hash_delete(n);
 643   _igvn.subsume_node( n, phi );
 644   // Moved a load around the loop, 'en-registering' something.
 645   if( n_blk->Opcode() == Op_Loop && n->is_Load() &&
 646       !phi->in(LoopNode::LoopBackControl)->is_Load() )
 647     C->set_major_progress();
 648 
 649   return phi;
 650 }
 651 
 652 static bool merge_point_too_heavy(Compile* C, Node* region) {
 653   // Bail out if the region and its phis have too many users.
 654   int weight = 0;
 655   for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
 656     weight += region->fast_out(i)->outcnt();
 657   }
 658   int nodes_left = MaxNodeLimit - C->unique();
 659   if (weight * 8 > nodes_left) {
 660 #ifndef PRODUCT
 661     if (PrintOpto)
 662       tty->print_cr("*** Split-if bails out:  %d nodes, region weight %d", C->unique(), weight);
 663 #endif
 664     return true;
 665   } else {
 666     return false;
 667   }
 668 }
 669 
 670 static bool merge_point_safe(Node* region) {
 671   // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
 672   // having a PhiNode input. This sidesteps the dangerous case where the split
 673   // ConvI2LNode may become TOP if the input Value() does not
 674   // overlap the ConvI2L range, leaving a node which may not dominate its
 675   // uses.
 676   // A better fix for this problem can be found in the BugTraq entry, but
 677   // expediency for Mantis demands this hack.
 678   // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop

 638   if( !phi ) return n;
 639 
 640   // Found a Phi to split thru!
 641   // Replace 'n' with the new phi
 642   _igvn.hash_delete(n);
 643   _igvn.subsume_node( n, phi );
 644   // Moved a load around the loop, 'en-registering' something.
 645   if( n_blk->Opcode() == Op_Loop && n->is_Load() &&
 646       !phi->in(LoopNode::LoopBackControl)->is_Load() )
 647     C->set_major_progress();
 648 
 649   return phi;
 650 }
 651 
 652 static bool merge_point_too_heavy(Compile* C, Node* region) {
 653   // Bail out if the region and its phis have too many users.
 654   int weight = 0;
 655   for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
 656     weight += region->fast_out(i)->outcnt();
 657   }
 658   int nodes_left = C->nodes_limit() - C->unique();
 659   if (weight * 8 > nodes_left) {
 660 #ifndef PRODUCT
 661     if (PrintOpto)
 662       tty->print_cr("*** Split-if bails out:  %d nodes, region weight %d", C->unique(), weight);
 663 #endif
 664     return true;
 665   } else {
 666     return false;
 667   }
 668 }
 669 
 670 static bool merge_point_safe(Node* region) {
 671   // 4799512: Stop split_if_with_blocks from splitting a block with a ConvI2LNode
 672   // having a PhiNode input. This sidesteps the dangerous case where the split
 673   // ConvI2LNode may become TOP if the input Value() does not
 674   // overlap the ConvI2L range, leaving a node which may not dominate its
 675   // uses.
 676   // A better fix for this problem can be found in the BugTraq entry, but
 677   // expediency for Mantis demands this hack.
 678   // 6855164: If the merge point has a FastLockNode with a PhiNode input, we stop