[AMDGPU] Combine DS operations with offsets bigger than byte

[rampitec]

Summary

In many cases ds operations can be combined even if offsets do not
fit into 8 bit encoding. What it takes is to adjust base address.

[vpykhtin]

Looks good.

lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

78 ↗

(On Diff #95040)

Why 3 offsets?

[rampitec]

lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

78 ↗

(On Diff #95040)

Two offsets as it will be encoded into an LDS instruction, and then base offset which needs to be added with v_add_i32 to the pointer if non zero.

[vpykhtin]

lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

78 ↗

(On Diff #95040)

But one of it would become zero in the instruction?

[rampitec]

lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

78 ↗

(On Diff #95040)

For now yes, either Offset0 or BaseOff are zero.

In a longer term that is not necessarily so. Imagine you could add less to the base pointer, use both offsets in the encoding, and then reuse new base register for another couple of registers, where this code will generate a separate v_add_i32 otherwise.

[vpykhtin]

lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

78 ↗

(On Diff #95040)

Right.

[arsenm]

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

387–389

This should use the e64 version with an unused carry. We should add a helper to TII to emit this since it will change with GFX9

392

BuildMI on next line and shift the .adds to the left

397–398

.setMemRefs

459–460

Same as with the other add

llvm/trunk/test/CodeGen/AMDGPU/ds-combine-large-stride.ll

1

-march is redundant with the triple. Should also use GCN check prefix since the check lines will need to change with GFX9 (should also add a run line for it so it breaks when the add change is made)

370

These all need to be marked amdgpu_kernel

[alekseyshl]

http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/2283 is broken by this change.

[rampitec]

In D31993#726539, @alekseyshl wrote:

http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/2283 is broken by this change.

Sure, will fix shortly.

[rampitec]

In D31993#726563, @rampitec wrote:

In D31993#726539, @alekseyshl wrote:

http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/2283 is broken by this change.

Sure, will fix shortly.

Oh, it is already fixed. Thanks!

[rampitec]

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

387–389

Matt, I doubt we should use e64 version here. It does not accept immediate, which effectively would require one more SGPR and one more mov. A vcc thrashing seems to be less issue.

[rampitec]

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

387–389

Even new no-carry variant is VOP3, so same issue.

[arsenm]

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

387–389

You can materialize the constant in a register. It will be folded and shrunk later

[rampitec]

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

387–389

It is not folded though:

s_movk_i32 s0, 0x960
v_add_i32_e32 v0, vcc, s0, v4
ds_read2_b32 v[0:1], v0 offset1:100

Also note, that values in this case will be mostly unique, because they are added to the base pointer, not to a previously incremented pointer. In latter case the would be high probability that many adds would have the same literal.

I would lean towards using e64 version and an SGPR when the pass is redesigned to first collect all pairs, build a chain of adds, and only then combine. In this case we will use single SGPR.

llvm/trunk/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp

 
 using namespace llvm;
 
 #define DEBUG_TYPE "si-load-store-opt"
 
 namespace {
 
 class SILoadStoreOptimizer : public MachineFunctionPass {
+
+  typedef struct {
+    MachineBasicBlock::iterator I;
+    MachineBasicBlock::iterator Paired;
+    unsigned EltSize;
+    unsigned Offset0;
+    unsigned Offset1;
+    unsigned BaseOff;
+    bool UseST64;
+    SmallVector<MachineInstr*, 8> InstsToMove;
+   } CombineInfo;
+
 private:
   const SIInstrInfo *TII = nullptr;
   const SIRegisterInfo *TRI = nullptr;
   MachineRegisterInfo *MRI = nullptr;
   AliasAnalysis *AA = nullptr;
 
-  static bool offsetsCanBeCombined(unsigned Offset0,
-                                   unsigned Offset1,
-                                   unsigned EltSize);
-
-  MachineBasicBlock::iterator findMatchingDSInst(
-    MachineBasicBlock::iterator I,
-    unsigned EltSize,
-    SmallVectorImpl<MachineInstr*> &InstsToMove);
-
-  MachineBasicBlock::iterator mergeRead2Pair(
-    MachineBasicBlock::iterator I,
-    MachineBasicBlock::iterator Paired,
-    unsigned EltSize,
-    ArrayRef<MachineInstr*> InstsToMove);
-
-  MachineBasicBlock::iterator mergeWrite2Pair(
-    MachineBasicBlock::iterator I,
-    MachineBasicBlock::iterator Paired,
-    unsigned EltSize,
-    ArrayRef<MachineInstr*> InstsToMove);
+  static bool offsetsCanBeCombined(CombineInfo &CI);
+
+  bool findMatchingDSInst(CombineInfo &CI);
+
+  MachineBasicBlock::iterator mergeRead2Pair(CombineInfo &CI);
+
+  MachineBasicBlock::iterator mergeWrite2Pair(CombineInfo &CI);
 
 public:
   static char ID;
 
   SILoadStoreOptimizer() : MachineFunctionPass(ID) {}
 
   SILoadStoreOptimizer(const TargetMachine &TM_) : MachineFunctionPass(ID) {
     initializeSILoadStoreOptimizerPass(*PassRegistry::getPassRegistry());
for (MachineInstr *InstToMove : InstsToMove) {
     if (!InstToMove->mayLoadOrStore())
       continue;
     if (!memAccessesCanBeReordered(MemOp, *InstToMove, TII, AA))
         return false;
   }
   return true;
 }
 
-bool SILoadStoreOptimizer::offsetsCanBeCombined(unsigned Offset0,
-                                                unsigned Offset1,
-                                                unsigned Size) {
+bool SILoadStoreOptimizer::offsetsCanBeCombined(CombineInfo &CI) {
   // XXX - Would the same offset be OK? Is there any reason this would happen or
   // be useful?
-  if (Offset0 == Offset1)
+  if (CI.Offset0 == CI.Offset1)
     return false;
 
   // This won't be valid if the offset isn't aligned.
-  if ((Offset0 % Size != 0) || (Offset1 % Size != 0))
+  if ((CI.Offset0 % CI.EltSize != 0) || (CI.Offset1 % CI.EltSize != 0))
     return false;
 
-  unsigned EltOffset0 = Offset0 / Size;
-  unsigned EltOffset1 = Offset1 / Size;
+  unsigned EltOffset0 = CI.Offset0 / CI.EltSize;
+  unsigned EltOffset1 = CI.Offset1 / CI.EltSize;
+  CI.UseST64 = false;
+  CI.BaseOff = 0;
+
+  // If the offset in elements doesn't fit in 8-bits, we might be able to use
+  // the stride 64 versions.
+  if ((EltOffset0 % 64 == 0) && (EltOffset1 % 64) == 0 &&
+      isUInt<8>(EltOffset0 / 64) && isUInt<8>(EltOffset1 / 64)) {
+    CI.Offset0 = EltOffset0 / 64;
+    CI.Offset1 = EltOffset1 / 64;
+    CI.UseST64 = true;
+    return true;
+  }
 
   // Check if the new offsets fit in the reduced 8-bit range.
-  if (isUInt<8>(EltOffset0) && isUInt<8>(EltOffset1))
+  if (isUInt<8>(EltOffset0) && isUInt<8>(EltOffset1)) {
+    CI.Offset0 = EltOffset0;
+    CI.Offset1 = EltOffset1;
     return true;
+  }
 
-  // If the offset in elements doesn't fit in 8-bits, we might be able to use
-  // the stride 64 versions.
-  if ((EltOffset0 % 64 != 0) || (EltOffset1 % 64) != 0)
-    return false;
+  // Try to shift base address to decrease offsets.
+  unsigned OffsetDiff = std::abs((int)EltOffset1 - (int)EltOffset0);
+  CI.BaseOff = std::min(CI.Offset0, CI.Offset1);
+
+  if ((OffsetDiff % 64 == 0) && isUInt<8>(OffsetDiff / 64)) {
+    CI.Offset0 = (EltOffset0 - CI.BaseOff / CI.EltSize) / 64;
+    CI.Offset1 = (EltOffset1 - CI.BaseOff / CI.EltSize) / 64;
+    CI.UseST64 = true;
+    return true;
+  }
+
+  if (isUInt<8>(OffsetDiff)) {
+    CI.Offset0 = EltOffset0 - CI.BaseOff / CI.EltSize;
+    CI.Offset1 = EltOffset1 - CI.BaseOff / CI.EltSize;
+    return true;
+  }
 
-  return isUInt<8>(EltOffset0 / 64) && isUInt<8>(EltOffset1 / 64);
+  return false;
 }
 
-MachineBasicBlock::iterator
-SILoadStoreOptimizer::findMatchingDSInst(MachineBasicBlock::iterator I,
-                                  unsigned EltSize,
-                                  SmallVectorImpl<MachineInstr*> &InstsToMove) {
-  MachineBasicBlock::iterator E = I->getParent()->end();
-  MachineBasicBlock::iterator MBBI = I;
+bool SILoadStoreOptimizer::findMatchingDSInst(CombineInfo &CI) {
+  MachineBasicBlock::iterator E = CI.I->getParent()->end();
+  MachineBasicBlock::iterator MBBI = CI.I;
   ++MBBI;
 
   SmallVector<const MachineOperand *, 8> DefsToMove;
-  addDefsToList(*I, DefsToMove);
+  addDefsToList(*CI.I, DefsToMove);
 
   for ( ; MBBI != E; ++MBBI) {
-    if (MBBI->getOpcode() != I->getOpcode()) {
+    if (MBBI->getOpcode() != CI.I->getOpcode()) {
 
       // This is not a matching DS instruction, but we can keep looking as
       // long as one of these conditions are met:
       // 1. It is safe to move I down past MBBI.
       // 2. It is safe to move MBBI down past the instruction that I will
       //    be merged into.
 
       if (MBBI->hasUnmodeledSideEffects())
         // We can't re-order this instruction with respect to other memory
         // opeations, so we fail both conditions mentioned above.
-        return E;
+        return false;
 
       if (MBBI->mayLoadOrStore() &&
-        !memAccessesCanBeReordered(*I, *MBBI, TII, AA)) {
+        !memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA)) {
         // We fail condition #1, but we may still be able to satisfy condition
         // #2.  Add this instruction to the move list and then we will check
         // if condition #2 holds once we have selected the matching instruction.
-        InstsToMove.push_back(&*MBBI);
+        CI.InstsToMove.push_back(&*MBBI);
         addDefsToList(*MBBI, DefsToMove);
         continue;
       }
 
       // When we match I with another DS instruction we will be moving I down
       // to the location of the matched instruction any uses of I will need to
       // be moved down as well.
-      addToListsIfDependent(*MBBI, DefsToMove, InstsToMove);
+      addToListsIfDependent(*MBBI, DefsToMove, CI.InstsToMove);
       continue;
     }
 
     // Don't merge volatiles.
     if (MBBI->hasOrderedMemoryRef())
-      return E;
+      return false;
 
     // Handle a case like
     //   DS_WRITE_B32 addr, v, idx0
     //   w = DS_READ_B32 addr, idx0
     //   DS_WRITE_B32 addr, f(w), idx1
     // where the DS_READ_B32 ends up in InstsToMove and therefore prevents
     // merging of the two writes.
-    if (addToListsIfDependent(*MBBI, DefsToMove, InstsToMove))
+    if (addToListsIfDependent(*MBBI, DefsToMove, CI.InstsToMove))
       continue;
 
-    int AddrIdx = AMDGPU::getNamedOperandIdx(I->getOpcode(), AMDGPU::OpName::addr);
-    const MachineOperand &AddrReg0 = I->getOperand(AddrIdx);
+    int AddrIdx = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(),
+                                             AMDGPU::OpName::addr);
+    const MachineOperand &AddrReg0 = CI.I->getOperand(AddrIdx);
     const MachineOperand &AddrReg1 = MBBI->getOperand(AddrIdx);
 
     // Check same base pointer. Be careful of subregisters, which can occur with
     // vectors of pointers.
     if (AddrReg0.getReg() == AddrReg1.getReg() &&
         AddrReg0.getSubReg() == AddrReg1.getSubReg()) {
-      int OffsetIdx = AMDGPU::getNamedOperandIdx(I->getOpcode(),
+      int OffsetIdx = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(),
                                                  AMDGPU::OpName::offset);
-      unsigned Offset0 = I->getOperand(OffsetIdx).getImm() & 0xffff;
-      unsigned Offset1 = MBBI->getOperand(OffsetIdx).getImm() & 0xffff;
+      CI.Offset0 = CI.I->getOperand(OffsetIdx).getImm() & 0xffff;
+      CI.Offset1 = MBBI->getOperand(OffsetIdx).getImm() & 0xffff;
+      CI.Paired = MBBI;
 
       // Check both offsets fit in the reduced range.
       // We also need to go through the list of instructions that we plan to
       // move and make sure they are all safe to move down past the merged
       // instruction.
-      if (offsetsCanBeCombined(Offset0, Offset1, EltSize) &&
-          canMoveInstsAcrossMemOp(*MBBI, InstsToMove, TII, AA))
-        return MBBI;
+      if (offsetsCanBeCombined(CI))
+        if (canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
+          return true;
     }
 
     // We've found a load/store that we couldn't merge for some reason.
     // We could potentially keep looking, but we'd need to make sure that
     // it was safe to move I and also all the instruction in InstsToMove
     // down past this instruction.
-    if (!memAccessesCanBeReordered(*I, *MBBI, TII, AA) ||   // check if we can move I across MBBI
-      !canMoveInstsAcrossMemOp(*MBBI, InstsToMove, TII, AA) // check if we can move all I's users
-     )
+    // check if we can move I across MBBI and if we can move all I's users
+    if (!memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA) ||
+      !canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
       break;
   }
-  return E;
+  return false;
 }
 
 MachineBasicBlock::iterator  SILoadStoreOptimizer::mergeRead2Pair(
-  MachineBasicBlock::iterator I,
-  MachineBasicBlock::iterator Paired,
-  unsigned EltSize,
-  ArrayRef<MachineInstr*> InstsToMove) {
-  MachineBasicBlock *MBB = I->getParent();
+  CombineInfo &CI) {
+  MachineBasicBlock *MBB = CI.I->getParent();
 
   // Be careful, since the addresses could be subregisters themselves in weird
   // cases, like vectors of pointers.
-  const MachineOperand *AddrReg = TII->getNamedOperand(*I, AMDGPU::OpName::addr);
+  const auto *AddrReg = TII->getNamedOperand(*CI.I, AMDGPU::OpName::addr);
 
-  const MachineOperand *Dest0 = TII->getNamedOperand(*I, AMDGPU::OpName::vdst);
-  const MachineOperand *Dest1 = TII->getNamedOperand(*Paired, AMDGPU::OpName::vdst);
+  const auto *Dest0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::vdst);
+  const auto *Dest1 = TII->getNamedOperand(*CI.Paired, AMDGPU::OpName::vdst);
 
-  unsigned Offset0
-    = TII->getNamedOperand(*I, AMDGPU::OpName::offset)->getImm() & 0xffff;
-  unsigned Offset1
-    = TII->getNamedOperand(*Paired, AMDGPU::OpName::offset)->getImm() & 0xffff;
-
-  unsigned NewOffset0 = Offset0 / EltSize;
-  unsigned NewOffset1 = Offset1 / EltSize;
-  unsigned Opc = (EltSize == 4) ? AMDGPU::DS_READ2_B32 : AMDGPU::DS_READ2_B64;
-
-  // Prefer the st64 form if we can use it, even if we can fit the offset in the
-  // non st64 version. I'm not sure if there's any real reason to do this.
-  bool UseST64 = (NewOffset0 % 64 == 0) && (NewOffset1 % 64 == 0);
-  if (UseST64) {
-    NewOffset0 /= 64;
-    NewOffset1 /= 64;
-    Opc = (EltSize == 4) ? AMDGPU::DS_READ2ST64_B32 : AMDGPU::DS_READ2ST64_B64;
-  }
+  unsigned NewOffset0 = CI.Offset0;
+  unsigned NewOffset1 = CI.Offset1;
+  unsigned Opc = (CI.EltSize == 4) ? AMDGPU::DS_READ2_B32
+                                   : AMDGPU::DS_READ2_B64;
+
+  if (CI.UseST64)
+    Opc = (CI.EltSize == 4) ? AMDGPU::DS_READ2ST64_B32
+                            : AMDGPU::DS_READ2ST64_B64;
 
-  unsigned SubRegIdx0 = (EltSize == 4) ? AMDGPU::sub0 : AMDGPU::sub0_sub1;
-  unsigned SubRegIdx1 = (EltSize == 4) ? AMDGPU::sub1 : AMDGPU::sub2_sub3;
+  unsigned SubRegIdx0 = (CI.EltSize == 4) ? AMDGPU::sub0 : AMDGPU::sub0_sub1;
+  unsigned SubRegIdx1 = (CI.EltSize == 4) ? AMDGPU::sub1 : AMDGPU::sub2_sub3;
 
   if (NewOffset0 > NewOffset1) {
     // Canonicalize the merged instruction so the smaller offset comes first.
     std::swap(NewOffset0, NewOffset1);
     std::swap(SubRegIdx0, SubRegIdx1);
   }
 
   assert((isUInt<8>(NewOffset0) && isUInt<8>(NewOffset1)) &&
          (NewOffset0 != NewOffset1) &&
          "Computed offset doesn't fit");
 
   const MCInstrDesc &Read2Desc = TII->get(Opc);
 
   const TargetRegisterClass *SuperRC
-    = (EltSize == 4) ? &AMDGPU::VReg_64RegClass : &AMDGPU::VReg_128RegClass;
+    = (CI.EltSize == 4) ? &AMDGPU::VReg_64RegClass : &AMDGPU::VReg_128RegClass;
   unsigned DestReg = MRI->createVirtualRegister(SuperRC);
 
-  DebugLoc DL = I->getDebugLoc();
-  MachineInstrBuilder Read2 = BuildMI(*MBB, Paired, DL, Read2Desc, DestReg)
-                                  .add(*AddrReg)      // addr
-                                  .addImm(NewOffset0) // offset0
-                                  .addImm(NewOffset1) // offset1
-                                  .addImm(0)          // gds
-                                  .addMemOperand(*I->memoperands_begin())
-                                  .addMemOperand(*Paired->memoperands_begin());
+  DebugLoc DL = CI.I->getDebugLoc();
+
+  unsigned BaseReg = AddrReg->getReg();
+  unsigned BaseRegFlags = 0;
+  if (CI.BaseOff) {
+    BaseReg = MRI->createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+    BaseRegFlags = RegState::Kill;
+    *BuildMI(*MBB, CI.Paired, DL, TII->get(AMDGPU::V_ADD_I32_e32), BaseReg)
+                        .addImm(CI.BaseOff)
+                        .addReg(AddrReg->getReg());
+  }
+
+  MachineInstrBuilder Read2 = BuildMI(*MBB, CI.Paired, DL, Read2Desc, DestReg)
+                                .addReg(BaseReg, BaseRegFlags) // addr
+                                .addImm(NewOffset0)            // offset0
+                                .addImm(NewOffset1)            // offset1
+                                .addImm(0)                     // gds
+                                .addMemOperand(*CI.I->memoperands_begin())
+                                .addMemOperand(*CI.Paired->memoperands_begin());
   (void)Read2;
 
   const MCInstrDesc &CopyDesc = TII->get(TargetOpcode::COPY);
 
   // Copy to the old destination registers.
-  BuildMI(*MBB, Paired, DL, CopyDesc)
+  BuildMI(*MBB, CI.Paired, DL, CopyDesc)
       .add(*Dest0) // Copy to same destination including flags and sub reg.
       .addReg(DestReg, 0, SubRegIdx0);
-  MachineInstr *Copy1 = BuildMI(*MBB, Paired, DL, CopyDesc)
+  MachineInstr *Copy1 = BuildMI(*MBB, CI.Paired, DL, CopyDesc)
                             .add(*Dest1)
                             .addReg(DestReg, RegState::Kill, SubRegIdx1);
 
-  moveInstsAfter(Copy1, InstsToMove);
+  moveInstsAfter(Copy1, CI.InstsToMove);
 
-  MachineBasicBlock::iterator Next = std::next(I);
-  I->eraseFromParent();
-  Paired->eraseFromParent();
+  MachineBasicBlock::iterator Next = std::next(CI.I);
+  CI.I->eraseFromParent();
+  CI.Paired->eraseFromParent();
 
   DEBUG(dbgs() << "Inserted read2: " << *Read2 << '\n');
   return Next;
 }
 
 MachineBasicBlock::iterator SILoadStoreOptimizer::mergeWrite2Pair(
-  MachineBasicBlock::iterator I,
-  MachineBasicBlock::iterator Paired,
-  unsigned EltSize,
-  ArrayRef<MachineInstr*> InstsToMove) {
-  MachineBasicBlock *MBB = I->getParent();
+  CombineInfo &CI) {
+  MachineBasicBlock *MBB = CI.I->getParent();
 
   // Be sure to use .addOperand(), and not .addReg() with these. We want to be
   // sure we preserve the subregister index and any register flags set on them.
-  const MachineOperand *Addr = TII->getNamedOperand(*I, AMDGPU::OpName::addr);
-  const MachineOperand *Data0 = TII->getNamedOperand(*I, AMDGPU::OpName::data0);
+  const MachineOperand *Addr = TII->getNamedOperand(*CI.I, AMDGPU::OpName::addr);
+  const MachineOperand *Data0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::data0);
   const MachineOperand *Data1
-    = TII->getNamedOperand(*Paired, AMDGPU::OpName::data0);
+    = TII->getNamedOperand(*CI.Paired, AMDGPU::OpName::data0);
 
-
-  unsigned Offset0
-    = TII->getNamedOperand(*I, AMDGPU::OpName::offset)->getImm() & 0xffff;
-  unsigned Offset1
-    = TII->getNamedOperand(*Paired, AMDGPU::OpName::offset)->getImm() & 0xffff;
-
-  unsigned NewOffset0 = Offset0 / EltSize;
-  unsigned NewOffset1 = Offset1 / EltSize;
-  unsigned Opc = (EltSize == 4) ? AMDGPU::DS_WRITE2_B32 : AMDGPU::DS_WRITE2_B64;
-
-  // Prefer the st64 form if we can use it, even if we can fit the offset in the
-  // non st64 version. I'm not sure if there's any real reason to do this.
-  bool UseST64 = (NewOffset0 % 64 == 0) && (NewOffset1 % 64 == 0);
-  if (UseST64) {
-    NewOffset0 /= 64;
-    NewOffset1 /= 64;
-    Opc = (EltSize == 4) ? AMDGPU::DS_WRITE2ST64_B32 : AMDGPU::DS_WRITE2ST64_B64;
-  }
+  unsigned NewOffset0 = CI.Offset0;
+  unsigned NewOffset1 = CI.Offset1;
+  unsigned Opc = (CI.EltSize == 4) ? AMDGPU::DS_WRITE2_B32
+                                   : AMDGPU::DS_WRITE2_B64;
+
+  if (CI.UseST64)
+    Opc = (CI.EltSize == 4) ? AMDGPU::DS_WRITE2ST64_B32
+                            : AMDGPU::DS_WRITE2ST64_B64;
 
   if (NewOffset0 > NewOffset1) {
     // Canonicalize the merged instruction so the smaller offset comes first.
     std::swap(NewOffset0, NewOffset1);
     std::swap(Data0, Data1);
   }
 
   assert((isUInt<8>(NewOffset0) && isUInt<8>(NewOffset1)) &&
          (NewOffset0 != NewOffset1) &&
          "Computed offset doesn't fit");
 
   const MCInstrDesc &Write2Desc = TII->get(Opc);
-  DebugLoc DL = I->getDebugLoc();
+  DebugLoc DL = CI.I->getDebugLoc();
+
+  unsigned BaseReg = Addr->getReg();
+  unsigned BaseRegFlags = 0;
+  if (CI.BaseOff) {
+    BaseReg = MRI->createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+    BaseRegFlags = RegState::Kill;
+    *BuildMI(*MBB, CI.Paired, DL, TII->get(AMDGPU::V_ADD_I32_e32), BaseReg)
+                        .addImm(CI.BaseOff)
+                        .addReg(Addr->getReg());
+  }
 
-  MachineInstrBuilder Write2 = BuildMI(*MBB, Paired, DL, Write2Desc)
-                                   .add(*Addr)         // addr
-                                   .add(*Data0)        // data0
-                                   .add(*Data1)        // data1
-                                   .addImm(NewOffset0) // offset0
-                                   .addImm(NewOffset1) // offset1
-                                   .addImm(0)          // gds
-                                   .addMemOperand(*I->memoperands_begin())
-                                   .addMemOperand(*Paired->memoperands_begin());
+  MachineInstrBuilder Write2 = BuildMI(*MBB, CI.Paired, DL, Write2Desc)
+                                .addReg(BaseReg, BaseRegFlags) // addr
+                                .add(*Data0)                   // data0
+                                .add(*Data1)                   // data1
+                                .addImm(NewOffset0)            // offset0
+                                .addImm(NewOffset1)            // offset1
+                                .addImm(0)                     // gds
+                                .addMemOperand(*CI.I->memoperands_begin())
+                                .addMemOperand(*CI.Paired->memoperands_begin());
 
-  moveInstsAfter(Write2, InstsToMove);
+  moveInstsAfter(Write2, CI.InstsToMove);
 
-  MachineBasicBlock::iterator Next = std::next(I);
-  I->eraseFromParent();
-  Paired->eraseFromParent();
+  MachineBasicBlock::iterator Next = std::next(CI.I);
+  CI.I->eraseFromParent();
+  CI.Paired->eraseFromParent();
 
   DEBUG(dbgs() << "Inserted write2 inst: " << *Write2 << '\n');
   return Next;
 }
 
 // Scan through looking for adjacent LDS operations with constant offsets from
 // the same base register. We rely on the scheduler to do the hard work of
 // clustering nearby loads, and assume these are all adjacent.
 bool SILoadStoreOptimizer::optimizeBlock(MachineBasicBlock &MBB) {
   bool Modified = false;
 
   for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E;) {
     MachineInstr &MI = *I;
 
     // Don't combine if volatile.
     if (MI.hasOrderedMemoryRef()) {
       ++I;
       continue;
     }
 
-    SmallVector<MachineInstr*, 8> InstsToMove;
+    CombineInfo CI;
+    CI.I = I;
     unsigned Opc = MI.getOpcode();
     if (Opc == AMDGPU::DS_READ_B32 || Opc == AMDGPU::DS_READ_B64) {
-      unsigned Size = (Opc == AMDGPU::DS_READ_B64) ? 8 : 4;
-      MachineBasicBlock::iterator Match = findMatchingDSInst(I, Size,
-                                                             InstsToMove);
-      if (Match != E) {
+      CI.EltSize = (Opc == AMDGPU::DS_READ_B64) ? 8 : 4;
+      if (findMatchingDSInst(CI)) {
         Modified = true;
-        I = mergeRead2Pair(I, Match, Size, InstsToMove);
+        I = mergeRead2Pair(CI);
       } else {
         ++I;
       }
 
       continue;
     } else if (Opc == AMDGPU::DS_WRITE_B32 || Opc == AMDGPU::DS_WRITE_B64) {
-      unsigned Size = (Opc == AMDGPU::DS_WRITE_B64) ? 8 : 4;
-      MachineBasicBlock::iterator Match = findMatchingDSInst(I, Size,
-                                                             InstsToMove);
-      if (Match != E) {
+      CI.EltSize = (Opc == AMDGPU::DS_WRITE_B64) ? 8 : 4;
+      if (findMatchingDSInst(CI)) {
         Modified = true;
-        I = mergeWrite2Pair(I, Match, Size, InstsToMove);
+        I = mergeWrite2Pair(CI);
       } else {
         ++I;
       }
 
       continue;
     }
 
     ++I;

llvm/trunk/test/CodeGen/AMDGPU/ds-combine-large-stride.ll

+; RUN: llc -march=amdgcn -mtriple=amdgcn--amdhsa -verify-machineinstrs < %s | FileCheck %s
+
+; CHECK-LABEL: ds_read32_combine_stride_400:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x320, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x640, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[BASE]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B1]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B2]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B3]] offset1:100
+define void @ds_read32_combine_stride_400(float addrspace(3)* nocapture readonly %arg, float *nocapture %arg1) {
+bb:
+  %tmp = load float, float addrspace(3)* %arg, align 4
+  %tmp2 = fadd float %tmp, 0.000000e+00
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 100
+  %tmp4 = load float, float addrspace(3)* %tmp3, align 4
+  %tmp5 = fadd float %tmp2, %tmp4
+  %tmp6 = getelementptr inbounds float, float addrspace(3)* %arg, i32 200
+  %tmp7 = load float, float addrspace(3)* %tmp6, align 4
+  %tmp8 = fadd float %tmp5, %tmp7
+  %tmp9 = getelementptr inbounds float, float addrspace(3)* %arg, i32 300
+  %tmp10 = load float, float addrspace(3)* %tmp9, align 4
+  %tmp11 = fadd float %tmp8, %tmp10
+  %tmp12 = getelementptr inbounds float, float addrspace(3)* %arg, i32 400
+  %tmp13 = load float, float addrspace(3)* %tmp12, align 4
+  %tmp14 = fadd float %tmp11, %tmp13
+  %tmp15 = getelementptr inbounds float, float addrspace(3)* %arg, i32 500
+  %tmp16 = load float, float addrspace(3)* %tmp15, align 4
+  %tmp17 = fadd float %tmp14, %tmp16
+  %tmp18 = getelementptr inbounds float, float addrspace(3)* %arg, i32 600
+  %tmp19 = load float, float addrspace(3)* %tmp18, align 4
+  %tmp20 = fadd float %tmp17, %tmp19
+  %tmp21 = getelementptr inbounds float, float addrspace(3)* %arg, i32 700
+  %tmp22 = load float, float addrspace(3)* %tmp21, align 4
+  %tmp23 = fadd float %tmp20, %tmp22
+  store float %tmp23, float *%arg1, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_read32_combine_stride_400_back:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x320, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x640, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[BASE]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B1]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B2]] offset1:100
+; CHECK-DAG: ds_read2_b32  v[{{[0-9]+:[0-9]+}}], [[B3]] offset1:100
+define void @ds_read32_combine_stride_400_back(float addrspace(3)* nocapture readonly %arg, float *nocapture %arg1) {
+bb:
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 700
+  %tmp2 = load float, float addrspace(3)* %tmp, align 4
+  %tmp3 = fadd float %tmp2, 0.000000e+00
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 600
+  %tmp5 = load float, float addrspace(3)* %tmp4, align 4
+  %tmp6 = fadd float %tmp3, %tmp5
+  %tmp7 = getelementptr inbounds float, float addrspace(3)* %arg, i32 500
+  %tmp8 = load float, float addrspace(3)* %tmp7, align 4
+  %tmp9 = fadd float %tmp6, %tmp8
+  %tmp10 = getelementptr inbounds float, float addrspace(3)* %arg, i32 400
+  %tmp11 = load float, float addrspace(3)* %tmp10, align 4
+  %tmp12 = fadd float %tmp9, %tmp11
+  %tmp13 = getelementptr inbounds float, float addrspace(3)* %arg, i32 300
+  %tmp14 = load float, float addrspace(3)* %tmp13, align 4
+  %tmp15 = fadd float %tmp12, %tmp14
+  %tmp16 = getelementptr inbounds float, float addrspace(3)* %arg, i32 200
+  %tmp17 = load float, float addrspace(3)* %tmp16, align 4
+  %tmp18 = fadd float %tmp15, %tmp17
+  %tmp19 = getelementptr inbounds float, float addrspace(3)* %arg, i32 100
+  %tmp20 = load float, float addrspace(3)* %tmp19, align 4
+  %tmp21 = fadd float %tmp18, %tmp20
+  %tmp22 = load float, float addrspace(3)* %arg, align 4
+  %tmp23 = fadd float %tmp21, %tmp22
+  store float %tmp23, float *%arg1, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_read32_combine_stride_8192:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[BASE]] offset1:32
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[BASE]] offset0:64 offset1:96
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[BASE]] offset0:128 offset1:160
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[BASE]] offset0:192 offset1:224
+define void @ds_read32_combine_stride_8192(float addrspace(3)* nocapture readonly %arg, float *nocapture %arg1) {
+bb:
+  %tmp = load float, float addrspace(3)* %arg, align 4
+  %tmp2 = fadd float %tmp, 0.000000e+00
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 2048
+  %tmp4 = load float, float addrspace(3)* %tmp3, align 4
+  %tmp5 = fadd float %tmp2, %tmp4
+  %tmp6 = getelementptr inbounds float, float addrspace(3)* %arg, i32 4096
+  %tmp7 = load float, float addrspace(3)* %tmp6, align 4
+  %tmp8 = fadd float %tmp5, %tmp7
+  %tmp9 = getelementptr inbounds float, float addrspace(3)* %arg, i32 6144
+  %tmp10 = load float, float addrspace(3)* %tmp9, align 4
+  %tmp11 = fadd float %tmp8, %tmp10
+  %tmp12 = getelementptr inbounds float, float addrspace(3)* %arg, i32 8192
+  %tmp13 = load float, float addrspace(3)* %tmp12, align 4
+  %tmp14 = fadd float %tmp11, %tmp13
+  %tmp15 = getelementptr inbounds float, float addrspace(3)* %arg, i32 10240
+  %tmp16 = load float, float addrspace(3)* %tmp15, align 4
+  %tmp17 = fadd float %tmp14, %tmp16
+  %tmp18 = getelementptr inbounds float, float addrspace(3)* %arg, i32 12288
+  %tmp19 = load float, float addrspace(3)* %tmp18, align 4
+  %tmp20 = fadd float %tmp17, %tmp19
+  %tmp21 = getelementptr inbounds float, float addrspace(3)* %arg, i32 14336
+  %tmp22 = load float, float addrspace(3)* %tmp21, align 4
+  %tmp23 = fadd float %tmp20, %tmp22
+  store float %tmp23, float *%arg1, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_read32_combine_stride_8192_shifted:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 8, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x4008, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x8008, [[BASE]]
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[B1]] offset1:32
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[B2]] offset1:32
+; CHECK-DAG: ds_read2st64_b32 v[{{[0-9]+:[0-9]+}}], [[B3]] offset1:32
+define void @ds_read32_combine_stride_8192_shifted(float addrspace(3)* nocapture readonly %arg, float *nocapture %arg1) {
+bb:
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 2
+  %tmp2 = load float, float addrspace(3)* %tmp, align 4
+  %tmp3 = fadd float %tmp2, 0.000000e+00
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 2050
+  %tmp5 = load float, float addrspace(3)* %tmp4, align 4
+  %tmp6 = fadd float %tmp3, %tmp5
+  %tmp7 = getelementptr inbounds float, float addrspace(3)* %arg, i32 4098
+  %tmp8 = load float, float addrspace(3)* %tmp7, align 4
+  %tmp9 = fadd float %tmp6, %tmp8
+  %tmp10 = getelementptr inbounds float, float addrspace(3)* %arg, i32 6146
+  %tmp11 = load float, float addrspace(3)* %tmp10, align 4
+  %tmp12 = fadd float %tmp9, %tmp11
+  %tmp13 = getelementptr inbounds float, float addrspace(3)* %arg, i32 8194
+  %tmp14 = load float, float addrspace(3)* %tmp13, align 4
+  %tmp15 = fadd float %tmp12, %tmp14
+  %tmp16 = getelementptr inbounds float, float addrspace(3)* %arg, i32 10242
+  %tmp17 = load float, float addrspace(3)* %tmp16, align 4
+  %tmp18 = fadd float %tmp15, %tmp17
+  store float %tmp18, float *%arg1, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_read64_combine_stride_400:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_read2_b64  v[{{[0-9]+:[0-9]+}}], [[BASE]] offset1:50
+; CHECK-DAG: ds_read2_b64  v[{{[0-9]+:[0-9]+}}], [[BASE]] offset0:100 offset1:150
+; CHECK-DAG: ds_read2_b64  v[{{[0-9]+:[0-9]+}}], [[BASE]] offset0:200 offset1:250
+; CHECK-DAG: ds_read2_b64  v[{{[0-9]+:[0-9]+}}], [[B1]] offset1:50
+define void @ds_read64_combine_stride_400(double addrspace(3)* nocapture readonly %arg, double *nocapture %arg1) {
+bb:
+  %tmp = load double, double addrspace(3)* %arg, align 8
+  %tmp2 = fadd double %tmp, 0.000000e+00
+  %tmp3 = getelementptr inbounds double, double addrspace(3)* %arg, i32 50
+  %tmp4 = load double, double addrspace(3)* %tmp3, align 8
+  %tmp5 = fadd double %tmp2, %tmp4
+  %tmp6 = getelementptr inbounds double, double addrspace(3)* %arg, i32 100
+  %tmp7 = load double, double addrspace(3)* %tmp6, align 8
+  %tmp8 = fadd double %tmp5, %tmp7
+  %tmp9 = getelementptr inbounds double, double addrspace(3)* %arg, i32 150
+  %tmp10 = load double, double addrspace(3)* %tmp9, align 8
+  %tmp11 = fadd double %tmp8, %tmp10
+  %tmp12 = getelementptr inbounds double, double addrspace(3)* %arg, i32 200
+  %tmp13 = load double, double addrspace(3)* %tmp12, align 8
+  %tmp14 = fadd double %tmp11, %tmp13
+  %tmp15 = getelementptr inbounds double, double addrspace(3)* %arg, i32 250
+  %tmp16 = load double, double addrspace(3)* %tmp15, align 8
+  %tmp17 = fadd double %tmp14, %tmp16
+  %tmp18 = getelementptr inbounds double, double addrspace(3)* %arg, i32 300
+  %tmp19 = load double, double addrspace(3)* %tmp18, align 8
+  %tmp20 = fadd double %tmp17, %tmp19
+  %tmp21 = getelementptr inbounds double, double addrspace(3)* %arg, i32 350
+  %tmp22 = load double, double addrspace(3)* %tmp21, align 8
+  %tmp23 = fadd double %tmp20, %tmp22
+  store double %tmp23, double *%arg1, align 8
+  ret void
+}
+
+; CHECK-LABEL: ds_read64_combine_stride_8192_shifted:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 8, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x4008, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x8008, [[BASE]]
+; CHECK-DAG: ds_read2st64_b64 v[{{[0-9]+:[0-9]+}}], [[B1]] offset1:16
+; CHECK-DAG: ds_read2st64_b64 v[{{[0-9]+:[0-9]+}}], [[B2]] offset1:16
+; CHECK-DAG: ds_read2st64_b64 v[{{[0-9]+:[0-9]+}}], [[B3]] offset1:16
+define void @ds_read64_combine_stride_8192_shifted(double addrspace(3)* nocapture readonly %arg, double *nocapture %arg1) {
+bb:
+  %tmp = getelementptr inbounds double, double addrspace(3)* %arg, i32 1
+  %tmp2 = load double, double addrspace(3)* %tmp, align 8
+  %tmp3 = fadd double %tmp2, 0.000000e+00
+  %tmp4 = getelementptr inbounds double, double addrspace(3)* %arg, i32 1025
+  %tmp5 = load double, double addrspace(3)* %tmp4, align 8
+  %tmp6 = fadd double %tmp3, %tmp5
+  %tmp7 = getelementptr inbounds double, double addrspace(3)* %arg, i32 2049
+  %tmp8 = load double, double addrspace(3)* %tmp7, align 8
+  %tmp9 = fadd double %tmp6, %tmp8
+  %tmp10 = getelementptr inbounds double, double addrspace(3)* %arg, i32 3073
+  %tmp11 = load double, double addrspace(3)* %tmp10, align 8
+  %tmp12 = fadd double %tmp9, %tmp11
+  %tmp13 = getelementptr inbounds double, double addrspace(3)* %arg, i32 4097
+  %tmp14 = load double, double addrspace(3)* %tmp13, align 8
+  %tmp15 = fadd double %tmp12, %tmp14
+  %tmp16 = getelementptr inbounds double, double addrspace(3)* %arg, i32 5121
+  %tmp17 = load double, double addrspace(3)* %tmp16, align 8
+  %tmp18 = fadd double %tmp15, %tmp17
+  store double %tmp18, double *%arg1, align 8
+  ret void
+}
+
+; CHECK-LABEL: ds_write32_combine_stride_400:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x320, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x640, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_write2_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B1]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B2]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B3]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+define void @ds_write32_combine_stride_400(float addrspace(3)* nocapture %arg) {
+bb:
+  store float 1.000000e+00, float addrspace(3)* %arg, align 4
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 100
+  store float 1.000000e+00, float addrspace(3)* %tmp, align 4
+  %tmp1 = getelementptr inbounds float, float addrspace(3)* %arg, i32 200
+  store float 1.000000e+00, float addrspace(3)* %tmp1, align 4
+  %tmp2 = getelementptr inbounds float, float addrspace(3)* %arg, i32 300
+  store float 1.000000e+00, float addrspace(3)* %tmp2, align 4
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 400
+  store float 1.000000e+00, float addrspace(3)* %tmp3, align 4
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 500
+  store float 1.000000e+00, float addrspace(3)* %tmp4, align 4
+  %tmp5 = getelementptr inbounds float, float addrspace(3)* %arg, i32 600
+  store float 1.000000e+00, float addrspace(3)* %tmp5, align 4
+  %tmp6 = getelementptr inbounds float, float addrspace(3)* %arg, i32 700
+  store float 1.000000e+00, float addrspace(3)* %tmp6, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_write32_combine_stride_400_back:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x320, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x640, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_write2_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B1]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B2]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+; CHECK-DAG: ds_write2_b32 [[B3]], v{{[0-9]+}}, v{{[0-9]+}} offset1:100
+define void @ds_write32_combine_stride_400_back(float addrspace(3)* nocapture %arg) {
+bb:
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 700
+  store float 1.000000e+00, float addrspace(3)* %tmp, align 4
+  %tmp1 = getelementptr inbounds float, float addrspace(3)* %arg, i32 600
+  store float 1.000000e+00, float addrspace(3)* %tmp1, align 4
+  %tmp2 = getelementptr inbounds float, float addrspace(3)* %arg, i32 500
+  store float 1.000000e+00, float addrspace(3)* %tmp2, align 4
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 400
+  store float 1.000000e+00, float addrspace(3)* %tmp3, align 4
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 300
+  store float 1.000000e+00, float addrspace(3)* %tmp4, align 4
+  %tmp5 = getelementptr inbounds float, float addrspace(3)* %arg, i32 200
+  store float 1.000000e+00, float addrspace(3)* %tmp5, align 4
+  %tmp6 = getelementptr inbounds float, float addrspace(3)* %arg, i32 100
+  store float 1.000000e+00, float addrspace(3)* %tmp6, align 4
+  store float 1.000000e+00, float addrspace(3)* %arg, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_write32_combine_stride_8192:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: ds_write2st64_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset1:32
+; CHECK-DAG: ds_write2st64_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset0:64 offset1:96
+; CHECK-DAG: ds_write2st64_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset0:128 offset1:160
+; CHECK-DAG: ds_write2st64_b32 [[BASE]], v{{[0-9]+}}, v{{[0-9]+}} offset0:192 offset1:224
+define void @ds_write32_combine_stride_8192(float addrspace(3)* nocapture %arg) {
+bb:
+  store float 1.000000e+00, float addrspace(3)* %arg, align 4
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 2048
+  store float 1.000000e+00, float addrspace(3)* %tmp, align 4
+  %tmp1 = getelementptr inbounds float, float addrspace(3)* %arg, i32 4096
+  store float 1.000000e+00, float addrspace(3)* %tmp1, align 4
+  %tmp2 = getelementptr inbounds float, float addrspace(3)* %arg, i32 6144
+  store float 1.000000e+00, float addrspace(3)* %tmp2, align 4
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 8192
+  store float 1.000000e+00, float addrspace(3)* %tmp3, align 4
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 10240
+  store float 1.000000e+00, float addrspace(3)* %tmp4, align 4
+  %tmp5 = getelementptr inbounds float, float addrspace(3)* %arg, i32 12288
+  store float 1.000000e+00, float addrspace(3)* %tmp5, align 4
+  %tmp6 = getelementptr inbounds float, float addrspace(3)* %arg, i32 14336
+  store float 1.000000e+00, float addrspace(3)* %tmp6, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_write32_combine_stride_8192_shifted:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 4, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x4004, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x8004, [[BASE]]
+; CHECK-DAG: ds_write2st64_b32 [[B1]], v{{[0-9]+}}, v{{[0-9]+}} offset1:32
+; CHECK-DAG: ds_write2st64_b32 [[B2]], v{{[0-9]+}}, v{{[0-9]+}} offset1:32
+; CHECK-DAG: ds_write2st64_b32 [[B3]], v{{[0-9]+}}, v{{[0-9]+}} offset1:32
+define void @ds_write32_combine_stride_8192_shifted(float addrspace(3)* nocapture %arg) {
+bb:
+  %tmp = getelementptr inbounds float, float addrspace(3)* %arg, i32 1
+  store float 1.000000e+00, float addrspace(3)* %tmp, align 4
+  %tmp1 = getelementptr inbounds float, float addrspace(3)* %arg, i32 2049
+  store float 1.000000e+00, float addrspace(3)* %tmp1, align 4
+  %tmp2 = getelementptr inbounds float, float addrspace(3)* %arg, i32 4097
+  store float 1.000000e+00, float addrspace(3)* %tmp2, align 4
+  %tmp3 = getelementptr inbounds float, float addrspace(3)* %arg, i32 6145
+  store float 1.000000e+00, float addrspace(3)* %tmp3, align 4
+  %tmp4 = getelementptr inbounds float, float addrspace(3)* %arg, i32 8193
+  store float 1.000000e+00, float addrspace(3)* %tmp4, align 4
+  %tmp5 = getelementptr inbounds float, float addrspace(3)* %arg, i32 10241
+  store float 1.000000e+00, float addrspace(3)* %tmp5, align 4
+  ret void
+}
+
+; CHECK-LABEL: ds_write64_combine_stride_400:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 0x960, [[BASE]]
+; CHECK-DAG: ds_write2_b64 [[BASE]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset1:50
+; CHECK-DAG: ds_write2_b64 [[BASE]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset0:100 offset1:150
+; CHECK-DAG: ds_write2_b64 [[BASE]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset0:200 offset1:250
+; CHECK-DAG: ds_write2_b64 [[B1]],   v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset1:50
+define void @ds_write64_combine_stride_400(double addrspace(3)* nocapture %arg) {
+bb:
+  store double 1.000000e+00, double addrspace(3)* %arg, align 8
+  %tmp = getelementptr inbounds double, double addrspace(3)* %arg, i32 50
+  store double 1.000000e+00, double addrspace(3)* %tmp, align 8
+  %tmp1 = getelementptr inbounds double, double addrspace(3)* %arg, i32 100
+  store double 1.000000e+00, double addrspace(3)* %tmp1, align 8
+  %tmp2 = getelementptr inbounds double, double addrspace(3)* %arg, i32 150
+  store double 1.000000e+00, double addrspace(3)* %tmp2, align 8
+  %tmp3 = getelementptr inbounds double, double addrspace(3)* %arg, i32 200
+  store double 1.000000e+00, double addrspace(3)* %tmp3, align 8
+  %tmp4 = getelementptr inbounds double, double addrspace(3)* %arg, i32 250
+  store double 1.000000e+00, double addrspace(3)* %tmp4, align 8
+  %tmp5 = getelementptr inbounds double, double addrspace(3)* %arg, i32 300
+  store double 1.000000e+00, double addrspace(3)* %tmp5, align 8
+  %tmp6 = getelementptr inbounds double, double addrspace(3)* %arg, i32 350
+  store double 1.000000e+00, double addrspace(3)* %tmp6, align 8
+  ret void
+}
+
+; CHECK-LABEL: ds_write64_combine_stride_8192_shifted:
+; CHECK:     s_load_dword [[ARG:s[0-9]+]], s[4:5], 0x0
+; CHECK:     v_mov_b32_e32 [[BASE:v[0-9]+]], [[ARG]]
+; CHECK-DAG: v_add_i32_e32 [[B1:v[0-9]+]], vcc, 8, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B2:v[0-9]+]], vcc, 0x4008, [[BASE]]
+; CHECK-DAG: v_add_i32_e32 [[B3:v[0-9]+]], vcc, 0x8008, [[BASE]]
+; CHECK-DAG: ds_write2st64_b64 [[B1]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset1:16
+; CHECK-DAG: ds_write2st64_b64 [[B2]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset1:16
+; CHECK-DAG: ds_write2st64_b64 [[B3]], v[{{[0-9]+:[0-9]+}}], v[{{[0-9]+:[0-9]+}}] offset1:16
+define void @ds_write64_combine_stride_8192_shifted(double addrspace(3)* nocapture %arg) {
+bb:
+  %tmp = getelementptr inbounds double, double addrspace(3)* %arg, i32 1
+  store double 1.000000e+00, double addrspace(3)* %tmp, align 8
+  %tmp1 = getelementptr inbounds double, double addrspace(3)* %arg, i32 1025
+  store double 1.000000e+00, double addrspace(3)* %tmp1, align 8
+  %tmp2 = getelementptr inbounds double, double addrspace(3)* %arg, i32 2049
+  store double 1.000000e+00, double addrspace(3)* %tmp2, align 8
+  %tmp3 = getelementptr inbounds double, double addrspace(3)* %arg, i32 3073
+  store double 1.000000e+00, double addrspace(3)* %tmp3, align 8
+  %tmp4 = getelementptr inbounds double, double addrspace(3)* %arg, i32 4097
+  store double 1.000000e+00, double addrspace(3)* %tmp4, align 8
+  %tmp5 = getelementptr inbounds double, double addrspace(3)* %arg, i32 5121
+  store double 1.000000e+00, double addrspace(3)* %tmp5, align 8
+  ret void
+}