Add another permutation where we should get rid of a-a.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61401 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index e3525df..fe29374 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1177,13 +1177,20 @@
return N0.getOperand(1);
// fold (A+B)-B -> A
if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
- return N0.getOperand(0);
- // fold ((A+(B-C))-B) -> A-C
+ return N0.getOperand(0);
+ // fold ((A+(B+-C))-B) -> A+-C
if (N0.getOpcode() == ISD::ADD &&
- N0.getOperand(1).getOpcode() == ISD::SUB &&
+ (N0.getOperand(1).getOpcode() == ISD::SUB ||
+ N0.getOperand(1).getOpcode() == ISD::ADD) &&
N0.getOperand(1).getOperand(0) == N1)
- return DAG.getNode(ISD::SUB, VT, N0.getOperand(0),
+ return DAG.getNode(N0.getOperand(1).getOpcode(), VT, N0.getOperand(0),
N0.getOperand(1).getOperand(1));
+ // fold ((A+(C+B))-B) -> A+C
+ if (N0.getOpcode() == ISD::ADD &&
+ N0.getOperand(1).getOpcode() == ISD::ADD &&
+ N0.getOperand(1).getOperand(1) == N1)
+ return DAG.getNode(ISD::ADD, VT, N0.getOperand(0),
+ N0.getOperand(1).getOperand(0));
// fold ((A-(B-C))-C) -> A-B
if (N0.getOpcode() == ISD::SUB &&
N0.getOperand(1).getOpcode() == ISD::SUB &&