Fix DSE to not nuke dead stores unless they redundant store is the same
VT as the killing one. Fix fixes PR491
llvm-svn: 24034
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 30c8d98..412b47e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1976,7 +1976,10 @@
// If this is a store that kills a previous store, remove the previous store.
if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr &&
- Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */) {
+ Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */ &&
+ // Make sure that these stores are the same value type:
+ // FIXME: we really care that the second store is >= size of the first.
+ Value.getValueType() == Chain.getOperand(1).getValueType()) {
// Create a new store of Value that replaces both stores.
SDNode *PrevStore = Chain.Val;
if (PrevStore->getOperand(1) == Value) // Same value multiply stored.