Author: lattner Date: Thu Jan 24 01:18:21 2008 New Revision: 46305 URL: http://llvm.org/viewvc/llvm-project?rev=46305&view=rev Log: The dag combiner is missing revisiting nodes that it really should, and thus leaving dead stuff around. This gets fed into the isel pass and causes certain foldings from happening because nodes have extraneous uses floating around. For example, if we turned foo(bar(x)) -> baz(x), we sometimes left bar(x) around.
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=46305&r1=46304&r2=46305&view=diff ============================================================================== --- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original) +++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Jan 24 01:18:21 2008 @@ -606,6 +606,11 @@ // Push the new node and any users onto the worklist AddToWorkList(RV.Val); AddUsersToWorkList(RV.Val); + + // Add any uses of the old node to the worklist if they have a single + // use. They may be dead after this node is deleted. + for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) + AddToWorkList(N->getOperand(i).Val); // Nodes can be reintroduced into the worklist. Make sure we do not // process a node that has been replaced. _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits