Teach DAG combiner to constant fold fneg of a BUILD_VECTOR of constants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163483 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 11145c4..4caafa5 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -413,7 +413,7 @@
!TLI.isOperationLegalOrCustom(ISD::FSUB, Op.getValueType()))
return 0;
- // fold (fsub (fadd A, B)) -> (fsub (fneg A), B)
+ // fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, TLI,
Options, Depth + 1))
return V;
@@ -6409,6 +6409,30 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
+ if (VT.isVector() && !LegalOperations) {
+ // If operand is a BUILD_VECTOR node, see if we can constant fold it.
+ if (N0.getOpcode() == ISD::BUILD_VECTOR) {
+ SmallVector<SDValue, 8> Ops;
+ for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) {
+ SDValue Op = N0.getOperand(i);
+ if (Op.getOpcode() != ISD::UNDEF &&
+ Op.getOpcode() != ISD::ConstantFP)
+ break;
+ EVT EltVT = Op.getValueType();
+ SDValue FoldOp = DAG.getNode(ISD::FNEG, N0.getDebugLoc(), EltVT, Op);
+ if (FoldOp.getOpcode() != ISD::UNDEF &&
+ FoldOp.getOpcode() != ISD::ConstantFP)
+ break;
+ Ops.push_back(FoldOp);
+ AddToWorkList(FoldOp.getNode());
+ }
+
+ if (Ops.size() == N0.getNumOperands())
+ return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
+ VT, &Ops[0], Ops.size());
+ }
+ }
+
if (isNegatibleForFree(N0, LegalOperations, DAG.getTargetLoweringInfo(),
&DAG.getTarget().Options))
return GetNegatedExpression(N0, DAG, LegalOperations);