Add generic expansion of SUB when ADD and XOR
are legal. Based on a patch by Micah Villmow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index bdcad0a..ca5f962 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3268,8 +3268,7 @@
OpToUse = ISD::UMUL_LOHI;
}
if (OpToUse) {
- Result = SDValue(DAG.getNode(OpToUse, dl, VTs, Tmp1, Tmp2).getNode(),
- 0);
+ Result = DAG.getNode(OpToUse, dl, VTs, Tmp1, Tmp2);
break;
}
}
@@ -3289,16 +3288,21 @@
}
if (Node->getOpcode() == ISD::SDIV &&
TLI.isOperationLegalOrCustom(ISD::SDIVREM, VT)) {
- Result = SDValue(DAG.getNode(ISD::SDIVREM, dl,
- VTs, Tmp1, Tmp2).getNode(),
- 0);
+ Result = DAG.getNode(ISD::SDIVREM, dl, VTs, Tmp1, Tmp2);
break;
}
if (Node->getOpcode() == ISD::UDIV &&
TLI.isOperationLegalOrCustom(ISD::UDIVREM, VT)) {
- Result = SDValue(DAG.getNode(ISD::UDIVREM, dl,
- VTs, Tmp1, Tmp2).getNode(),
- 0);
+ Result = DAG.getNode(ISD::UDIVREM, dl, VTs, Tmp1, Tmp2);
+ break;
+ }
+ if (Node->getOpcode() == ISD::SUB &&
+ TLI.isOperationLegalOrCustom(ISD::ADD, VT) &&
+ TLI.isOperationLegalOrCustom(ISD::XOR, VT)) {
+ Tmp2 = DAG.getNode(ISD::XOR, dl, VT, Tmp2,
+ DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), VT));
+ Tmp2 = DAG.getNode(ISD::ADD, dl, VT, Tmp2, DAG.getConstant(1, VT));
+ Result = DAG.getNode(ISD::ADD, dl, VT, Tmp1, Tmp2);
break;
}