Make it simplier to dump DAGs while in DAGCombiner. Remove a nasty optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31009 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 474ae28..997820d 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -49,7 +49,7 @@
static cl::opt<bool>
CombinerAA("combiner-alias-analysis", cl::Hidden,
- cl::desc("Turn on alias analysis turning testing"));
+ cl::desc("Turn on alias analysis during testing"));
//------------------------------ DAGCombiner ---------------------------------//
@@ -388,6 +388,9 @@
// changes of the root.
HandleSDNode Dummy(DAG.getRoot());
+ // The root of the dag may dangle to deleted nodes until the dag combiner is
+ // done. Set it to null to avoid confusion.
+ DAG.setRoot(SDOperand());
/// DagCombineInfo - Expose the DAG combiner to the target combiner impls.
TargetLowering::DAGCombinerInfo
@@ -2759,13 +2762,6 @@
}
if (CombinerAA) {
- // If the store ptr is a frame index and the frame index has a use of one
- // and this is a return block, then the store is redundant.
- if (Ptr.hasOneUse() && isa<FrameIndexSDNode>(Ptr) &&
- DAG.getRoot().getOpcode() == ISD::RET) {
- return Chain;
- }
-
// Walk up chain skipping non-aliasing memory nodes.
SDOperand BetterChain = FindBetterChain(N, Chain);