Add a case we were missing that was causing us to fail CodeGen/PowerPC/rlwinm.ll:test3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23755 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 879dc5b..35c981d 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -803,6 +803,20 @@
WorkList.push_back(ANDNode.Val);
return DAG.getNode(N0.getOpcode(), VT, ANDNode, N0.getOperand(1));
}
+ // fold (and (sra)) -> (and (srl)) when possible.
+ if (N0.getOpcode() == ISD::SRA && N0.Val->hasOneUse())
+ if (ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
+ // If the RHS of the AND has zeros where the sign bits of the SRA will
+ // land, turn the SRA into an SRL.
+ if (MaskedValueIsZero(N1, (~0ULL << N01C->getValue()) &
+ (~0ULL>>(64-OpSizeInBits)), TLI)) {
+ WorkList.push_back(N);
+ CombineTo(N0.Val, DAG.getNode(ISD::SRL, VT, N0.getOperand(0),
+ N0.getOperand(1)));
+ return SDOperand();
+ }
+ }
+
// fold (zext_inreg (extload x)) -> (zextload x)
if (N0.getOpcode() == ISD::EXTLOAD) {
MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT();