GlobalISel: Use helper function for MMO splitting

Also fix an alignment bug getMachineMemOperand. If the
tracked value is null, the offset isn't tracked so the
base alignment needs to be reduced.

llvm-svn: 352716

Author: arsenm

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -568,20 +568,18 @@ LegalizerHelper::LegalizeResult LegalizerHelper::narrowScalar(MachineInstr &MI,
     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 PartDstReg = 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(PartDstReg, SrcReg, *SplitMMO);
 
@@ -684,18 +682,16 @@ LegalizerHelper::LegalizeResult LegalizerHelper::narrowScalar(MachineInstr &MI,
     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);
     }

llvm/lib/CodeGen/MachineFunction.cpp

@@ -395,19 +395,18 @@ MachineMemOperand *MachineFunction::getMachineMemOperand(
 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 *