diff options
| author | Dale Johannesen <dalej@apple.com> | 2008-12-23 23:01:27 +0000 |
|---|---|---|
| committer | Dale Johannesen <dalej@apple.com> | 2008-12-23 23:01:27 +0000 |
| commit | f9cbc1f9ac087937641c16b218d10986f5b406ad (patch) | |
| tree | 10dc90e88dd1824ae49c40a865d8a177b6e1ea37 /lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | c7a37d4ff2ee8ffb93ba97e9393ff582f0e79a9a (diff) | |
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
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index e3525df181..fe29374256 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1177,13 +1177,20 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { 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 && |