[SelectionDAG][X86] Explicitly store the scale in the gather/scatter ISD nodes

Currently we infer the scale at isel time by analyzing whether the base is a constant 0 or not. If it is we assume scale is 1, else we take it from the element size of the pass thru or stored value. This seems a little weird and I think it makes more sense to make it explicit in the DAG rather than doing tricky things in the backend.

Most of this patch is just making sure we copy the scale around everywhere.

Differential Revision: https://reviews.llvm.org/D40055

llvm-svn: 322210

1 files changed, 8 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f229be15c5d..1820d5f944f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6726,6 +6726,7 @@ SDValue DAGCombiner::visitMSCATTER(SDNode *N) {
   SDValue DataLo, DataHi;
   std::tie(DataLo, DataHi) = DAG.SplitVector(Data, DL);
 
+  SDValue Scale = MSC->getScale();
   SDValue BasePtr = MSC->getBasePtr();
   SDValue IndexLo, IndexHi;
   std::tie(IndexLo, IndexHi) = DAG.SplitVector(MSC->getIndex(), DL);
@@ -6735,11 +6736,11 @@ SDValue DAGCombiner::visitMSCATTER(SDNode *N) {
                           MachineMemOperand::MOStore,  LoMemVT.getStoreSize(),
                           Alignment, MSC->getAAInfo(), MSC->getRanges());
 
-  SDValue OpsLo[] = { Chain, DataLo, MaskLo, BasePtr, IndexLo };
+  SDValue OpsLo[] = { Chain, DataLo, MaskLo, BasePtr, IndexLo, Scale };
   Lo = DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataLo.getValueType(),
                             DL, OpsLo, MMO);
 
-  SDValue OpsHi[] = {Chain, DataHi, MaskHi, BasePtr, IndexHi};
+  SDValue OpsHi[] = { Chain, DataHi, MaskHi, BasePtr, IndexHi, Scale };
   Hi = DAG.getMaskedScatter(DAG.getVTList(MVT::Other), DataHi.getValueType(),
                             DL, OpsHi, MMO);
 
@@ -6859,6 +6860,7 @@ SDValue DAGCombiner::visitMGATHER(SDNode *N) {
   EVT LoMemVT, HiMemVT;
   std::tie(LoMemVT, HiMemVT) = DAG.GetSplitDestVTs(MemoryVT);
 
+  SDValue Scale = MGT->getScale();
   SDValue BasePtr = MGT->getBasePtr();
   SDValue Index = MGT->getIndex();
   SDValue IndexLo, IndexHi;
@@ -6869,13 +6871,13 @@ SDValue DAGCombiner::visitMGATHER(SDNode *N) {
                           MachineMemOperand::MOLoad,  LoMemVT.getStoreSize(),
                           Alignment, MGT->getAAInfo(), MGT->getRanges());
 
-  SDValue OpsLo[] = { Chain, Src0Lo, MaskLo, BasePtr, IndexLo };
+  SDValue OpsLo[] = { Chain, Src0Lo, MaskLo, BasePtr, IndexLo, Scale };
   Lo = DAG.getMaskedGather(DAG.getVTList(LoVT, MVT::Other), LoVT, DL, OpsLo,
-                            MMO);
+                           MMO);
 
-  SDValue OpsHi[] = {Chain, Src0Hi, MaskHi, BasePtr, IndexHi};
+  SDValue OpsHi[] = { Chain, Src0Hi, MaskHi, BasePtr, IndexHi, Scale };
   Hi = DAG.getMaskedGather(DAG.getVTList(HiVT, MVT::Other), HiVT, DL, OpsHi,
-                            MMO);
+                           MMO);
 
   AddToWorklist(Lo.getNode());
   AddToWorklist(Hi.getNode());