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Fix chain dropping in load and drop unused stores in ret blocks. 

llvm-svn: 30600
This commit is contained in:
Jim Laskey 2006-09-25 19:32:58 +00:00
parent 437d9a3fb2
commit b5534e5c28
1 changed files with 14 additions and 7 deletions
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17
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -2650,13 +2650,13 @@ SDOperand DAGCombiner::visitLOAD(SDNode *N) {
SDOperand ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr,
SrcValue);
// Replace uses with token.
CombineTo(N, ReplLoad.getValue(0), ReplLoad.getValue(1));
// Create token factor to keep chain around.
SDOperand Token = DAG.getNode(ISD::TokenFactor, MVT::Other,
Chain, ReplLoad.getValue(1));
// Old chain needs to be cleaned up.
AddToWorkList(Chain.Val);
// Replace uses with load and token factor.
CombineTo(N, ReplLoad.getValue(0), Token);
// Don't recombine on token.
return SDOperand(N, 0);
}
}
@ -2712,6 +2712,13 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) {
}
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);