Index: lib/CodeGen/GlobalISel/LegalizerHelper.cpp
===================================================================
--- lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -489,20 +489,18 @@
     LLT OffsetTy = LLT::scalar(
         MRI.getType(MI.getOperand(1).getReg()).getScalarSizeInBits());
 
+    MachineFunction &MF = MIRBuilder.getMF();
     SmallVector<unsigned, 2> DstRegs;
     for (int i = 0; i < NumParts; ++i) {
       unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
       unsigned SrcReg = 0;
-      unsigned Adjustment = i * NarrowSize / 8;
-      unsigned Alignment = MinAlign(MMO.getAlignment(), Adjustment);
+      unsigned Offset = i * NarrowSize / 8;
 
-      MachineMemOperand *SplitMMO = MIRBuilder.getMF().getMachineMemOperand(
-          MMO.getPointerInfo().getWithOffset(Adjustment), MMO.getFlags(),
-          NarrowSize / 8, Alignment, MMO.getAAInfo(), MMO.getRanges(),
-          MMO.getSyncScopeID(), MMO.getOrdering(), MMO.getFailureOrdering());
+      MachineMemOperand *SplitMMO =
+          MF.getMachineMemOperand(&MMO, Offset, NarrowSize / 8);
 
       MIRBuilder.materializeGEP(SrcReg, MI.getOperand(1).getReg(), OffsetTy,
-                                Adjustment);
+                                Offset);
 
       MIRBuilder.buildLoad(DstReg, SrcReg, *SplitMMO);
 
@@ -563,18 +561,16 @@
     SmallVector<unsigned, 2> SrcRegs;
     extractParts(MI.getOperand(0).getReg(), NarrowTy, NumParts, SrcRegs);
 
+    MachineFunction &MF = MIRBuilder.getMF();
     for (int i = 0; i < NumParts; ++i) {
       unsigned DstReg = 0;
-      unsigned Adjustment = i * NarrowSize / 8;
-      unsigned Alignment = MinAlign(MMO.getAlignment(), Adjustment);
+      unsigned Offset = i * NarrowSize / 8;
 
-      MachineMemOperand *SplitMMO = MIRBuilder.getMF().getMachineMemOperand(
-          MMO.getPointerInfo().getWithOffset(Adjustment), MMO.getFlags(),
-          NarrowSize / 8, Alignment, MMO.getAAInfo(), MMO.getRanges(),
-          MMO.getSyncScopeID(), MMO.getOrdering(), MMO.getFailureOrdering());
+      MachineMemOperand *SplitMMO =
+          MF.getMachineMemOperand(&MMO, Offset, NarrowSize / 8);
 
       MIRBuilder.materializeGEP(DstReg, MI.getOperand(1).getReg(), OffsetTy,
-                                Adjustment);
+                                Offset);
 
       MIRBuilder.buildStore(SrcRegs[i], DstReg, *SplitMMO);
     }
Index: lib/CodeGen/MachineFunction.cpp
===================================================================
--- lib/CodeGen/MachineFunction.cpp
+++ lib/CodeGen/MachineFunction.cpp
@@ -395,19 +395,18 @@
 MachineMemOperand *
 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
                                       int64_t Offset, uint64_t Size) {
-  if (MMO->getValue())
-    return new (Allocator)
-               MachineMemOperand(MachinePointerInfo(MMO->getValue(),
-                                                    MMO->getOffset()+Offset),
-                                 MMO->getFlags(), Size, MMO->getBaseAlignment(),
-                                 AAMDNodes(), nullptr, MMO->getSyncScopeID(),
-                                 MMO->getOrdering(), MMO->getFailureOrdering());
+  const MachinePointerInfo &PtrInfo = MMO->getPointerInfo();
+
+  // If there is no pointer value, the offset isn't tracked so we need to adjust
+  // the base alignment.
+  unsigned Align = PtrInfo.V.isNull()
+                       ? MinAlign(MMO->getBaseAlignment(), Offset)
+                       : MMO->getBaseAlignment();
+
   return new (Allocator)
-             MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
-                                                  MMO->getOffset()+Offset),
-                               MMO->getFlags(), Size, MMO->getBaseAlignment(),
-                               AAMDNodes(), nullptr, MMO->getSyncScopeID(),
-                               MMO->getOrdering(), MMO->getFailureOrdering());
+      MachineMemOperand(PtrInfo.getWithOffset(Offset), MMO->getFlags(), Size,
+                        Align, AAMDNodes(), nullptr, MMO->getSyncScopeID(),
+                        MMO->getOrdering(), MMO->getFailureOrdering());
 }
 
 MachineMemOperand *