[GlobalISel] LegalizerHelper: Implement fewerElementsVector for G_LOAD/G_STORE

Reviewers: aemerson, dsanders, bogner, paquette, aditya_nandakumar

Reviewed By: dsanders

Subscribers: rovka, kristof.beyls, javed.absar, tschuett, llvm-commits

Differential Revision: https://reviews.llvm.org/D53728

llvm-svn: 349200

1 files changed, 44 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 6926c9cfc31..890ef52dd3d 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1128,6 +1128,8 @@ LegalizerHelper::fewerElementsVector(MachineInstr &MI, unsigned TypeIdx,
   // FIXME: Don't know how to handle secondary types yet.
   if (TypeIdx != 0)
     return UnableToLegalize;
+
+  MIRBuilder.setInstr(MI);
   switch (MI.getOpcode()) {
   default:
     return UnableToLegalize;
@@ -1141,8 +1143,6 @@ LegalizerHelper::fewerElementsVector(MachineInstr &MI, unsigned TypeIdx,
     if (Size % NarrowSize != 0)
       return UnableToLegalize;
 
-    MIRBuilder.setInstr(MI);
-
     SmallVector<unsigned, 2> Src1Regs, Src2Regs, DstRegs;
     extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, Src1Regs);
     extractParts(MI.getOperand(2).getReg(), NarrowTy, NumParts, Src2Regs);
@@ -1157,6 +1157,48 @@ LegalizerHelper::fewerElementsVector(MachineInstr &MI, unsigned TypeIdx,
     MI.eraseFromParent();
     return Legalized;
   }
+  case TargetOpcode::G_LOAD:
+  case TargetOpcode::G_STORE: {
+    bool IsLoad = MI.getOpcode() == TargetOpcode::G_LOAD;
+    unsigned ValReg = MI.getOperand(0).getReg();
+    unsigned AddrReg = MI.getOperand(1).getReg();
+    unsigned NarrowSize = NarrowTy.getSizeInBits();
+    unsigned Size = MRI.getType(ValReg).getSizeInBits();
+    unsigned NumParts = Size / NarrowSize;
+
+    SmallVector<unsigned, 8> NarrowRegs;
+    if (!IsLoad)
+      extractParts(ValReg, NarrowTy, NumParts, NarrowRegs);
+
+    const LLT OffsetTy =
+        LLT::scalar(MRI.getType(AddrReg).getScalarSizeInBits());
+    MachineFunction &MF = *MI.getMF();
+    MachineMemOperand *MMO = *MI.memoperands_begin();
+    for (unsigned Idx = 0; Idx < NumParts; ++Idx) {
+      unsigned Adjustment = Idx * NarrowTy.getSizeInBits() / 8;
+      unsigned Alignment = MinAlign(MMO->getAlignment(), Adjustment);
+      unsigned NewAddrReg = 0;
+      MIRBuilder.materializeGEP(NewAddrReg, AddrReg, OffsetTy, Adjustment);
+      MachineMemOperand &NewMMO = *MF.getMachineMemOperand(
+          MMO->getPointerInfo().getWithOffset(Adjustment), MMO->getFlags(),
+          NarrowTy.getSizeInBits() / 8, Alignment);
+      if (IsLoad) {
+        unsigned Dst = MRI.createGenericVirtualRegister(NarrowTy);
+        NarrowRegs.push_back(Dst);
+        MIRBuilder.buildLoad(Dst, NewAddrReg, NewMMO);
+      } else {
+        MIRBuilder.buildStore(NarrowRegs[Idx], NewAddrReg, NewMMO);
+      }
+    }
+    if (IsLoad) {
+      if (NarrowTy.isVector())
+        MIRBuilder.buildConcatVectors(ValReg, NarrowRegs);
+      else
+        MIRBuilder.buildBuildVector(ValReg, NarrowRegs);
+    }
+    MI.eraseFromParent();
+    return Legalized;
+  }
   }
 }