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| author | Chris Lattner <sabre@nondot.org> | 2005-04-10 04:04:49 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2005-04-10 04:04:49 +0000 |
| commit | edeecfcbd5ae3fe6d7e65107203a93ed196aaf1b (patch) | |
| tree | cc31ac38effbf8caccada8d7ec7113f96690f2f1 /lib/CodeGen/SelectionDAG/SelectionDAG.cpp | |
| parent | 340f2907839cc5ecb34c5045cb24ef31588f2a39 (diff) | |
add a simple xform
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21203 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAG.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index f33ecd7223..7cf89144c3 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -892,6 +892,12 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, return getNode(ISD::SUB, VT, N1, N2.getOperand(0)); if (N1.getOpcode() == ISD::FNEG) // ((-A)+B) -> B-A return getNode(ISD::SUB, VT, N2, N1.getOperand(0)); + if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && + cast<ConstantSDNode>(N1.getOperand(0))->getValue() == 0) + return getNode(ISD::SUB, VT, N2, N1.getOperand(1)); // (0-A)+B -> B-A + if (N2.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N2.getOperand(0)) && + cast<ConstantSDNode>(N2.getOperand(0))->getValue() == 0) + return getNode(ISD::SUB, VT, N1, N2.getOperand(1)); // A+(0-B) -> A-B break; case ISD::SUB: if (N1.getOpcode() == ISD::ADD) { |