[X86] Use Align in reduceMaskedLoadToScalarLoad/reduceMaskedStoreToScalarStore. Correct pointer info.

[craig.topper]

Summary

If we offset the pointer, we also need to offset the pointer info

[RKSimon]

Any useful test cases?

[craig.topper]

Add mir test cases to show change to memory operand

[RKSimon]

LGTM

llvm/lib/Target/X86/X86ISelLowering.cpp

 }
 
 /// Given a masked memory load/store operation, return true if it has one mask
 /// bit set. If it has one mask bit set, then also return the memory address of
 /// the scalar element to load/store, the vector index to insert/extract that
 /// scalar element, and the alignment for the scalar memory access.
 static bool getParamsForOneTrueMaskedElt(MaskedLoadStoreSDNode *MaskedOp,
                                          SelectionDAG &DAG, SDValue &Addr,
-                                         SDValue &Index, unsigned &Alignment) {
+                                         SDValue &Index, Align &Alignment,
+                                         unsigned &Offset) {
   int TrueMaskElt = getOneTrueElt(MaskedOp->getMask());
   if (TrueMaskElt < 0)
     return false;
 
   // Get the address of the one scalar element that is specified by the mask
   // using the appropriate offset from the base pointer.
   EVT EltVT = MaskedOp->getMemoryVT().getVectorElementType();
+  Offset = 0;
   Addr = MaskedOp->getBasePtr();
   if (TrueMaskElt != 0) {
-    unsigned Offset = TrueMaskElt * EltVT.getStoreSize();
+    Offset = TrueMaskElt * EltVT.getStoreSize();
     Addr = DAG.getMemBasePlusOffset(Addr, TypeSize::Fixed(Offset),
                                     SDLoc(MaskedOp));
   }
 
   Index = DAG.getIntPtrConstant(TrueMaskElt, SDLoc(MaskedOp));
-  Alignment = MinAlign(MaskedOp->getAlignment(), EltVT.getStoreSize());
+  Alignment = commonAlignment(MaskedOp->getOriginalAlign(),
+                              EltVT.getStoreSize());
   return true;
 }
 
 /// If exactly one element of the mask is set for a non-extending masked load,
 /// it is a scalar load and vector insert.
 /// Note: It is expected that the degenerate cases of an all-zeros or all-ones
 /// mask have already been optimized in IR, so we don't bother with those here.
 static SDValue
 reduceMaskedLoadToScalarLoad(MaskedLoadSDNode *ML, SelectionDAG &DAG,
                              TargetLowering::DAGCombinerInfo &DCI) {
   assert(ML->isUnindexed() && "Unexpected indexed masked load!");
   // TODO: This is not x86-specific, so it could be lifted to DAGCombiner.
   // However, some target hooks may need to be added to know when the transform
   // is profitable. Endianness would also have to be considered.
 
   SDValue Addr, VecIndex;
-  unsigned Alignment;
-  if (!getParamsForOneTrueMaskedElt(ML, DAG, Addr, VecIndex, Alignment))
+  Align Alignment;
+  unsigned Offset;
+  if (!getParamsForOneTrueMaskedElt(ML, DAG, Addr, VecIndex, Alignment, Offset))
     return SDValue();
 
   // Load the one scalar element that is specified by the mask using the
   // appropriate offset from the base pointer.
   SDLoc DL(ML);
   EVT VT = ML->getValueType(0);
   EVT EltVT = VT.getVectorElementType();
   SDValue Load =
-      DAG.getLoad(EltVT, DL, ML->getChain(), Addr, ML->getPointerInfo(),
+      DAG.getLoad(EltVT, DL, ML->getChain(), Addr,
+                  ML->getPointerInfo().getWithOffset(Offset),
                   Alignment, ML->getMemOperand()->getFlags());
 
   // Insert the loaded element into the appropriate place in the vector.
   SDValue Insert = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, VT,
                                ML->getPassThru(), Load, VecIndex);
   return DCI.CombineTo(ML, Insert, Load.getValue(1), true);
 }
 

 /// mask have already been optimized in IR, so we don't bother with those here.
 static SDValue reduceMaskedStoreToScalarStore(MaskedStoreSDNode *MS,
                                               SelectionDAG &DAG) {
   // TODO: This is not x86-specific, so it could be lifted to DAGCombiner.
   // However, some target hooks may need to be added to know when the transform
   // is profitable. Endianness would also have to be considered.
 
   SDValue Addr, VecIndex;
-  unsigned Alignment;
-  if (!getParamsForOneTrueMaskedElt(MS, DAG, Addr, VecIndex, Alignment))
+  Align Alignment;
+  unsigned Offset;
+  if (!getParamsForOneTrueMaskedElt(MS, DAG, Addr, VecIndex, Alignment, Offset))
     return SDValue();
 
   // Extract the one scalar element that is actually being stored.
   SDLoc DL(MS);
   EVT VT = MS->getValue().getValueType();
   EVT EltVT = VT.getVectorElementType();
   SDValue Extract = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT,
                                 MS->getValue(), VecIndex);
 
   // Store that element at the appropriate offset from the base pointer.
-  return DAG.getStore(MS->getChain(), DL, Extract, Addr, MS->getPointerInfo(),
+  return DAG.getStore(MS->getChain(), DL, Extract, Addr,
+                      MS->getPointerInfo().getWithOffset(Offset),
                       Alignment, MS->getMemOperand()->getFlags());
 }
 
 static SDValue combineMaskedStore(SDNode *N, SelectionDAG &DAG,
                                   TargetLowering::DAGCombinerInfo &DCI,
                                   const X86Subtarget &Subtarget) {
   MaskedStoreSDNode *Mst = cast<MaskedStoreSDNode>(N);
   if (Mst->isCompressingStore())