Add comment.
llvm-svn: 31473
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 03abac2..eee7a8f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -174,7 +174,13 @@
return true;
}
- bool CombineToIndexedLoadStore(SDNode *N) {
+ /// CombineToPreIndexedLoadStore - Try turning a load / store into a
+ /// pre-indexed load store when the base pointer is a add or subtract
+ /// and it has other uses besides the load / store. When the
+ /// transformation is done, the new indexed load / store effectively
+ /// folded the add / subtract in and all of its other uses are redirected
+ /// to the new load / store.
+ bool CombineToPreIndexedLoadStore(SDNode *N) {
bool isLoad = true;
SDOperand Ptr;
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
@@ -811,7 +817,7 @@
return DAG.getNode(ISD::OR, VT, N0, N1);
}
}
-
+
return SDOperand();
}
@@ -2871,7 +2877,7 @@
}
// Try transforming N to an indexed load.
- if (CombineToIndexedLoadStore(N))
+ if (CombineToPreIndexedLoadStore(N))
return SDOperand(N, 0);
return SDOperand();
@@ -2917,7 +2923,7 @@
}
// Try transforming N to an indexed store.
- if (CombineToIndexedLoadStore(N))
+ if (CombineToPreIndexedLoadStore(N))
return SDOperand(N, 0);
return SDOperand();