Remove this xform:
(shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2)
Replace it with:
(add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
This fixes test/CodeGen/ARM/smul.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33361 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 654f6c5..fa48d54 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -653,6 +653,22 @@
return Result;
}
+static
+SDOperand combineShlAddConstant(SDOperand N0, SDOperand N1, SelectionDAG &DAG) {
+ MVT::ValueType VT = N0.getValueType();
+ SDOperand N00 = N0.getOperand(0);
+ SDOperand N01 = N0.getOperand(1);
+ ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01);
+ if (N01C && N00.getOpcode() == ISD::ADD && N00.Val->hasOneUse() &&
+ isa<ConstantSDNode>(N00.getOperand(1))) {
+ N0 = DAG.getNode(ISD::ADD, VT,
+ DAG.getNode(ISD::SHL, VT, N00.getOperand(0), N01),
+ DAG.getNode(ISD::SHL, VT, N00.getOperand(1), N01));
+ return DAG.getNode(ISD::ADD, VT, N0, N1);
+ }
+ return SDOperand();
+}
+
SDOperand DAGCombiner::visitADD(SDNode *N) {
SDOperand N0 = N->getOperand(0);
SDOperand N1 = N->getOperand(1);
@@ -711,6 +727,16 @@
}
}
+ // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
+ if (N0.getOpcode() == ISD::SHL && N0.Val->hasOneUse()) {
+ SDOperand Result = combineShlAddConstant(N0, N1, DAG);
+ if (Result.Val) return Result;
+ }
+ if (N1.getOpcode() == ISD::SHL && N1.Val->hasOneUse()) {
+ SDOperand Result = combineShlAddConstant(N1, N0, DAG);
+ if (Result.Val) return Result;
+ }
+
return SDOperand();
}
@@ -1615,13 +1641,6 @@
if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1))
return DAG.getNode(ISD::AND, VT, N0.getOperand(0),
DAG.getConstant(~0ULL << N1C->getValue(), VT));
- // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2)
- if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() &&
- isa<ConstantSDNode>(N0.getOperand(1))) {
- return DAG.getNode(ISD::ADD, VT,
- DAG.getNode(ISD::SHL, VT, N0.getOperand(0), N1),
- DAG.getNode(ISD::SHL, VT, N0.getOperand(1), N1));
- }
return SDOperand();
}