Fixed a bug in splitting Scatter operation in the Type Legalizer.

After the split of the Scatter operation, the order of the new instructions is well defined - Lo goes before Hi. Otherwise the semantic of Scatter (from LSB to MSB) is broken.
I'm chaining 2 nodes to prevent reordering.

Differential Revision https://reviews.llvm.org/D37670

llvm-svn: 312894

1 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index b65f47eff1c..b2839414173 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -1970,13 +1970,12 @@ SDValue DAGTypeLegalizer::SplitVecOp_MSCATTER(MaskedScatterSDNode *N,
                          MachineMemOperand::MOStore,  HiMemVT.getStoreSize(),
                          Alignment, N->getAAInfo(), N->getRanges());
 
-  SDValue OpsHi[] = {Ch, DataHi, MaskHi, Ptr, IndexHi};
-  Hi = DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataHi.getValueType(),
-                            DL, OpsHi, MMO);
-
-  // Build a factor node to remember that this store is independent of the
-  // other one.
-  return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Lo, Hi);
+  // The order of the Scatter operation after split is well defined. The "Hi"
+  // part comes after the "Lo". So these two operations should be chained one
+  // after another.
+  SDValue OpsHi[] = {Lo, DataHi, MaskHi, Ptr, IndexHi};
+  return DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataHi.getValueType(),
+                              DL, OpsHi, MMO);
 }
 
 SDValue DAGTypeLegalizer::SplitVecOp_STORE(StoreSDNode *N, unsigned OpNo) {