Fix chain dropping in load and drop unused stores in ret blocks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30600 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index c7823ff..e4fdedf 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2650,13 +2650,13 @@
SDOperand ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr,
SrcValue);
- // Replace uses with token.
- CombineTo(N, ReplLoad.getValue(0), ReplLoad.getValue(1));
-
- // Old chain needs to be cleaned up.
- AddToWorkList(Chain.Val);
-
- // Don't recombine on token.
+ // Create token factor to keep chain around.
+ SDOperand Token = DAG.getNode(ISD::TokenFactor, MVT::Other,
+ Chain, ReplLoad.getValue(1));
+
+ // Replace uses with load and token factor.
+ CombineTo(N, ReplLoad.getValue(0), Token);
+
return SDOperand(N, 0);
}
}
@@ -2712,6 +2712,13 @@
}
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);