[AArch64][SelectionDAG] Add legalization for widening LOAD/MLOAD.

[efriedma]

Summary

By the magic of masked loads, a widened MLOAD is almost identical to the original MLOAD.

Need to handle a few more INSERT_SUBVECTOR legalization cases to avoid crashing on the testcase.

The code for computing the mask is unfortunately not very efficient; maybe we need a target-independent version of whilelo? Or a DAGCombine to form whilelo?

[sdesmalen]

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

4048

Do we also want to do this for other element-counts that are not a power of 2? (e.g. <vscale x 6 x i8>)

Was this code intended to work for <vscale x 1 x eltty> ? (I tried that a few days ago with this patch and ran into some failures. I didn't really investigate further though)

4049

nit: VT.isKnownMultipleOf(2)

4135

Should MemoryLocation::UnknownSize only be used for the scalable case?

[efriedma]

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

4048

Should work for 1, I guess? Not sure I actually tried it. But note we only support a very limited set of operations. See also D105591.

For <vscale x 6 x i8>, we can use a different sequence: generate extloads for <vscale x 2 x i64> and <vscale x 4 x i32>, and merge them together. GenWidenVectorLoads should handle that in theory; not sure how well it works in practice.

I'll add more testcases, in any case.

4135

There's a general restriction on memoperands in selectiondag: the size of the operand must be at least the size of the memory VT. I didn't really want to think about precisely what MemoryLocation we could be using instead...

[efriedma]

More tests. Make "<vscale x 1 x i32>" loads work.

[sdesmalen]

Apologies for the delay in reviewing this, it has been on my to-do list for quite a while!

Thanks for adding support for <vscale x 1 x eltty> types and adding a test for widening the even-numbered ElementCounts (e.g. <vscale x 6 x i16>), it's nice to see that this works too.

Other than some minor comments, the patch looks mostly fine to me.

llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

4881–4883 ↗

(On Diff #359931)

nit: Is/would this be the same as:

SDValue Op0 = N->getOperand(0);
TLI.getTypeToTransformTo(*DAG.getContext(), Op0.getValueType());

?

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

4011

This code is identical to the block on lines 4022-4026, with the exception of s/NumElements/MinNumElements. Can you align the implementation in the two blocks and remove the if (VT.isScalableVector())? (and then move the report_fatal_error to line 4027)

4017

nit: unnecessary curly braces.

4048

Is the FIXME still relevant?

For <vscale x 6 x i8>, we can use a different sequence: generate extloads for <vscale x 2 x i64> and <vscale x 4 x i32>, and merge them together. GenWidenVectorLoads should handle that in theory; not sure how well it works in practice.
I'll add more testcases, in any case.

Nice. From what I can see from the test you've added, <vscale x 6 x i16> is handled correctly by GenWidenVectorLoads.

4054

nit: can you move WidenVT closer to where it's used? (above line 4079)

llvm/test/CodeGen/AArch64/sve-split-load.ll

72

sve-split-load.ll may no longer be the best name for this file given that these new tests are about widening?

[efriedma]

llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

4881–4883 ↗

(On Diff #359931)

No, it's not the same.

We need to extend the element VT to the element VT of the result type. For SVE, the resulting vector type is usually promotable. If it is, we deal with it in PromoteIntOp_CONCAT_VECTORS.

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

4048

Yes, it's still an issue. The constant "2" is specific to SVE.

The question we need to figure out here is, will GenWidenVectorLoads succeed (and be profitable)? For SVE, it should succeed for any multiple of 2, because we can use 64-bit extending loads. Not sure about profitability for SVE; the generated code is a bit messy, but the messy bits are all invariant (and probably less messy once we start using whilelo optimally).

Other vector instruction sets might have different restrictions.

llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

void DAGTypeLegalizer::SplitVecRes_INSERT_SUBVECTOR(SDNode *N, SDValue &Lo,
   // of a scalable vector.
   if (VecVT.isScalableVector() == SubVecVT.isScalableVector() &&
       IdxVal >= LoElems && IdxVal + SubElems <= VecElems) {
     Hi = DAG.getNode(ISD::INSERT_SUBVECTOR, dl, Hi.getValueType(), Hi, SubVec,
                      DAG.getVectorIdxConstant(IdxVal - LoElems, dl));
     return;
   }
 
+  // insert_subvector(Op, SubVec, 0) where SubVec widens to the result type
+  // can be converted to a vselect.
+  if (IdxVal == 0 && VecVT.isScalableVector() &&
+      TLI.getTypeToTransformTo(*DAG.getContext(), SubVecVT) == VecVT) {
+    SDValue WidenedSubVec = GetWidenedVector(SubVec);
+    EVT CmpElementVT = MVT::i32;
+    EVT CmpVT = EVT::getVectorVT(*DAG.getContext(), CmpElementVT,
+                                 VecVT.getVectorElementCount());
+    EVT MaskVT = EVT::getVectorVT(*DAG.getContext(), MVT::i1,
+                                  VecVT.getVectorElementCount());
+
+    SDLoc dl(N);
+    SDValue Step = DAG.getStepVector(dl, CmpVT);
+    unsigned NumElements = SubVec.getValueType().getVectorMinNumElements();
+    SDValue SplatNumElements = DAG.getSplatVector(
+        CmpVT, dl, DAG.getVScale(dl, CmpElementVT, APInt(32, NumElements)));
+    SDValue Mask =
+        DAG.getSetCC(dl, MaskVT, Step, SplatNumElements, ISD::SETULT);
+    SDValue Select =
+        DAG.getNode(ISD::VSELECT, dl, VecVT, Mask, WidenedSubVec, Vec);
+
+    Lo = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, Lo.getValueType(), Select,
+                     DAG.getVectorIdxConstant(0, dl));
+    Hi = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, Hi.getValueType(), Select,
+                     DAG.getVectorIdxConstant(LoElems, dl));
+    return;
+  }
+
   // Spill the vector to the stack.
   // In cases where the vector is illegal it will be broken down into parts
   // and stored in parts - we should use the alignment for the smallest part.
   Align SmallestAlign = DAG.getReducedAlign(VecVT, /*UseABI=*/false);
   SDValue StackPtr =
       DAG.CreateStackTemporary(VecVT.getStoreSize(), SmallestAlign);
   auto &MF = DAG.getMachineFunction();
   auto FrameIndex = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
SDValue DAGTypeLegalizer::WidenVecRes_EXTRACT_SUBVECTOR(SDNode *N) {
   EVT InVT = InOp.getValueType();
 
   // Check if we can just return the input vector after widening.
   uint64_t IdxVal = cast<ConstantSDNode>(Idx)->getZExtValue();
   if (IdxVal == 0 && InVT == WidenVT)
     return InOp;
 
   if (VT.isScalableVector())
     report_fatal_error("Don't know how to widen the result of "
                        "EXTRACT_SUBVECTOR for scalable vectors");
 
   // Check if we can extract from the vector.
   unsigned WidenNumElts = WidenVT.getVectorNumElements();
   unsigned InNumElts = InVT.getVectorNumElements();
   if (IdxVal % WidenNumElts == 0 && IdxVal + WidenNumElts < InNumElts)
     return DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, WidenVT, InOp, Idx);
 
   // We could try widening the input to the right length but for now, extract
   // the original elements, fill the rest with undefs and build a vector.
   SmallVector<SDValue, 16> Ops(WidenNumElts);
   EVT EltVT = VT.getVectorElementType();
   unsigned NumElts = VT.getVectorNumElements();
   unsigned i;
SDValue DAGTypeLegalizer::WidenVecRes_INSERT_VECTOR_ELT(SDNode *N) {
   return DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(N),
                      InOp.getValueType(), InOp,
                      N->getOperand(1), N->getOperand(2));
 }
 
 SDValue DAGTypeLegalizer::WidenVecRes_LOAD(SDNode *N) {
   LoadSDNode *LD = cast<LoadSDNode>(N);
   ISD::LoadExtType ExtType = LD->getExtensionType();
+  EVT VT = N->getValueType(0);
+
+  // FIXME: Figure out how to replace constant "2".
+  if (VT.isScalableVector() && VT.getVectorMinNumElements() % 2 != 0) {
+    // Convert load to masked load. Let MLOAD legalization handle widening.
+    // (We assume hardware with scalable vectors supports masked load/store.)
+    SDLoc dl(N);
+    EVT WidenVT = TLI.getTypeToTransformTo(*DAG.getContext(), VT);
+    EVT MaskVT = EVT::getVectorVT(*DAG.getContext(), MVT::i1,
+                                  VT.getVectorElementCount());
+    SDValue Mask = DAG.getAllOnesConstant(dl, MaskVT);
+    SDValue PassThru = DAG.getUNDEF(VT);
+
+    // Convert load to masked load. Let MLOAD legalization handle widening.
+    SDValue Res = DAG.getMaskedLoad(VT, dl, LD->getChain(), LD->getBasePtr(),
+                                    LD->getOffset(), Mask, PassThru,
+                                    LD->getMemoryVT(), LD->getMemOperand(),
+                                    LD->getAddressingMode(), ExtType);
+
+    // Legalize the chain result - switch anything that used the old chain to
+    // use the new one.
+    ReplaceValueWith(SDValue(N, 1), Res.getValue(1));
+
+    // Widen the result.
+    return DAG.getNode(ISD::INSERT_SUBVECTOR, dl, WidenVT,
+                       DAG.getUNDEF(WidenVT), Res,
+                       DAG.getVectorIdxConstant(0, dl));
+  }
 
   // A vector must always be stored in memory as-is, i.e. without any padding
   // between the elements, since various code depend on it, e.g. in the
   // handling of a bitcast of a vector type to int, which may be done with a
   // vector store followed by an integer load. A vector that does not have
   // elements that are byte-sized must therefore be stored as an integer
   // built out of the extracted vector elements.
   if (!LD->getMemoryVT().isByteSized()) {
SDValue DAGTypeLegalizer::WidenVecRes_LOAD(SDNode *N) {
   // Modified the chain - switch anything that used the old chain to use
   // the new one.
   ReplaceValueWith(SDValue(N, 1), NewChain);
 
   return Result;
 }
 
 SDValue DAGTypeLegalizer::WidenVecRes_MLOAD(MaskedLoadSDNode *N) {
+  assert(N->getAddressingMode() == ISD::UNINDEXED &&
+         "We shouldn't form indexed loads with illegal types");
 
-  EVT WidenVT = TLI.getTypeToTransformTo(*DAG.getContext(),N->getValueType(0));
+  EVT WidenVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
   SDValue Mask = N->getMask();
   EVT MaskVT = Mask.getValueType();
   SDValue PassThru = GetWidenedVector(N->getPassThru());
   ISD::LoadExtType ExtType = N->getExtensionType();
   SDLoc dl(N);
 
   // The mask should be widened as well
-  EVT WideMaskVT = EVT::getVectorVT(*DAG.getContext(),
-                                    MaskVT.getVectorElementType(),
-                                    WidenVT.getVectorNumElements());
+  EVT WideMaskVT =
+      EVT::getVectorVT(*DAG.getContext(), MaskVT.getVectorElementType(),
+                       WidenVT.getVectorElementCount());
   Mask = ModifyToType(Mask, WideMaskVT, true);
 
-  SDValue Res = DAG.getMaskedLoad(
-      WidenVT, dl, N->getChain(), N->getBasePtr(), N->getOffset(), Mask,
-      PassThru, N->getMemoryVT(), N->getMemOperand(), N->getAddressingMode(),
-      ExtType, N->isExpandingLoad());
+  EVT MemVT = N->getMemoryVT();
+  EVT WideMemVT =
+      EVT::getVectorVT(*DAG.getContext(), MemVT.getVectorElementType(),
+                       WidenVT.getVectorElementCount());
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineMemOperand *MemOp = MF.getMachineMemOperand(
+      N->getMemOperand(), 0, MemoryLocation::UnknownSize);
+
+  SDValue Res =
+      DAG.getMaskedLoad(WidenVT, dl, N->getChain(), N->getBasePtr(),
+                        N->getOffset(), Mask, PassThru, WideMemVT, MemOp,
+                        ISD::UNINDEXED, ExtType, N->isExpandingLoad());
   // Legalize the chain result - switch anything that used the old chain to
   // use the new one.
   ReplaceValueWith(SDValue(N, 1), Res.getValue(1));
   return Res;
 }
 
 SDValue DAGTypeLegalizer::WidenVecRes_MGATHER(MaskedGatherSDNode *N) {
 
SDValue DAGTypeLegalizer::WidenVecOp_INSERT_SUBVECTOR(SDNode *N) {
 
   if (getTypeAction(SubVec.getValueType()) == TargetLowering::TypeWidenVector)
     SubVec = GetWidenedVector(SubVec);
 
   if (SubVec.getValueType() == InVec.getValueType() && InVec.isUndef() &&
       N->getConstantOperandVal(2) == 0)
     return SubVec;
 
+  if (SubVec.getValueType() == InVec.getValueType() &&
+      InVec.getValueType().isScalableVector() &&
+      N->getConstantOperandVal(2) == 0) {
+    EVT VT = InVec.getValueType();
+    EVT CmpElementVT = MVT::i32;
+    EVT CmpVT = EVT::getVectorVT(*DAG.getContext(), CmpElementVT,
+                                 VT.getVectorElementCount());
+    EVT MaskVT = EVT::getVectorVT(*DAG.getContext(), MVT::i1,
+                                  VT.getVectorElementCount());
+
+    SDLoc dl(N);
+    SDValue Step = DAG.getStepVector(dl, CmpVT);
+    unsigned NumElements = SubVec.getValueType().getVectorMinNumElements();
+    SDValue SplatNumElements = DAG.getSplatVector(
+        CmpVT, dl, DAG.getVScale(dl, CmpElementVT, APInt(32, NumElements)));
+    SDValue Mask =
+        DAG.getSetCC(dl, MaskVT, Step, SplatNumElements, ISD::SETULT);
+    return DAG.getNode(ISD::VSELECT, dl, VT, Mask, SubVec, InVec);
+  }
+
   report_fatal_error("Don't know how to widen the operands for "
                      "INSERT_SUBVECTOR");
 }
 
 SDValue DAGTypeLegalizer::WidenVecOp_EXTRACT_SUBVECTOR(SDNode *N) {
   SDValue InOp = GetWidenedVector(N->getOperand(0));
   return DAG.getNode(ISD::EXTRACT_SUBVECTOR, SDLoc(N),
                      N->getValueType(0), InOp, N->getOperand(1));
SDValue DAGTypeLegalizer::ModifyToType(SDValue InOp, EVT NVT,
   assert(InVT.getVectorElementType() == NVT.getVectorElementType() &&
          "input and widen element type must match");
   SDLoc dl(InOp);
 
   // Check if InOp already has the right width.
   if (InVT == NVT)
     return InOp;
 
-  unsigned InNumElts = InVT.getVectorNumElements();
-  unsigned WidenNumElts = NVT.getVectorNumElements();
+  unsigned InNumElts = InVT.getVectorMinNumElements();
+  unsigned WidenNumElts = NVT.getVectorMinNumElements();
   if (WidenNumElts > InNumElts && WidenNumElts % InNumElts == 0) {
     unsigned NumConcat = WidenNumElts / InNumElts;
     SmallVector<SDValue, 16> Ops(NumConcat);
     SDValue FillVal = FillWithZeroes ? DAG.getConstant(0, dl, InVT) :
       DAG.getUNDEF(InVT);
     Ops[0] = InOp;
     for (unsigned i = 1; i != NumConcat; ++i)
       Ops[i] = FillVal;
 
     return DAG.getNode(ISD::CONCAT_VECTORS, dl, NVT, Ops);
   }
 
   if (WidenNumElts < InNumElts && InNumElts % WidenNumElts)
     return DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, NVT, InOp,
                        DAG.getVectorIdxConstant(0, dl));
 
+  if (NVT.isScalableVector()) {
+    if (WidenNumElts < InNumElts)
+      return DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, NVT, InOp,
+                         DAG.getVectorIdxConstant(0, dl));
+
+    SDValue FillVal =
+        FillWithZeroes ? DAG.getConstant(0, dl, NVT) : DAG.getUNDEF(NVT);
+    return DAG.getNode(ISD::INSERT_SUBVECTOR, dl, NVT, FillVal, InOp,
+                       DAG.getVectorIdxConstant(0, dl));
+  }
+
   // Fall back to extract and build.
   SmallVector<SDValue, 16> Ops(WidenNumElts);
   EVT EltVT = NVT.getVectorElementType();
   unsigned MinNumElts = std::min(WidenNumElts, InNumElts);
   unsigned Idx;
   for (Idx = 0; Idx < MinNumElts; ++Idx)
     Ops[Idx] = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, EltVT, InOp,
                            DAG.getVectorIdxConstant(Idx, dl));

llvm/test/CodeGen/AArch64/sve-split-load.ll

 ; CHECK-NEXT:    ld1h { z0.h }, p0/z, [x0]
 ; CHECK-NEXT:    ld1h { z1.h }, p0/z, [x0, #1, mul vl]
 ; CHECK-NEXT:    ld1h { z2.h }, p0/z, [x0, #2, mul vl]
 ; CHECK-NEXT:    ret
   %load = load <vscale x 24 x i16>, <vscale x 24 x i16>* %a
   ret <vscale x 24 x i16> %load
 }
 
+define <vscale x 4 x i32> @load_widen_3i32(<vscale x 3 x i32>* %a) {
+; CHECK-LABEL: load_widen_3i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    index z0.s, #0, #1
+; CHECK-NEXT:    mov z1.s, w8
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    cmphi p0.s, p0/z, z1.s, z0.s
+; CHECK-NEXT:    ld1w { z0.s }, p0/z, [x0]
+; CHECK-NEXT:    ret
+  %load = load <vscale x 3 x i32>, <vscale x 3 x i32>* %a
+  %r = call <vscale x 4 x i32> @llvm.experimental.vector.insert.nxv4i32.nxv3i32(<vscale x 4 x i32> undef, <vscale x 3 x i32> %load, i64 0)
+  ret <vscale x 4 x i32> %r
+}
+
+define <vscale x 8 x i32> @load_widen_7i32(<vscale x 7 x i32>* %a) {
+; CHECK-LABEL: load_widen_7i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x9
+; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    index z0.s, #0, #1
+; CHECK-NEXT:    mov z2.s, w9
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    mov z1.s, w8
+; CHECK-NEXT:    add z2.s, z0.s, z2.s
+; CHECK-NEXT:    cmphi p1.s, p0/z, z1.s, z0.s
+; CHECK-NEXT:    cmphi p0.s, p0/z, z1.s, z2.s
+; CHECK-NEXT:    ld1w { z0.s }, p1/z, [x0]
+; CHECK-NEXT:    ld1w { z1.s }, p0/z, [x0, #1, mul vl]
+; CHECK-NEXT:    ret
+  %load = load <vscale x 7 x i32>, <vscale x 7 x i32>* %a
+  %r = call <vscale x 8 x i32> @llvm.experimental.vector.insert.nxv8i32.nxv7i32(<vscale x 8 x i32> undef, <vscale x 7 x i32> %load, i64 0)
+  ret <vscale x 8 x i32> %r
+}
+
 define <vscale x 32 x i16> @load_split_32i16(<vscale x 32 x i16>* %a) {
 ; CHECK-LABEL: load_split_32i16:
 ; CHECK:       // %bb.0:
 ; CHECK-NEXT:    ptrue p0.h
 ; CHECK-NEXT:    ld1h { z0.h }, p0/z, [x0]
 ; CHECK-NEXT:    ld1h { z1.h }, p0/z, [x0, #1, mul vl]
 ; CHECK-NEXT:    ld1h { z2.h }, p0/z, [x0, #2, mul vl]
 ; CHECK-NEXT:    ld1h { z3.h }, p0/z, [x0, #3, mul vl]

 ; CHECK-NEXT:    zip2 p0.s, p0.s, p1.s
 ; CHECK-NEXT:    ld1d { z2.d }, p2/z, [x0, #2, mul vl]
 ; CHECK-NEXT:    ld1d { z3.d }, p0/z, [x0, #3, mul vl]
 ; CHECK-NEXT:    ret
   %load = call <vscale x 8 x i64> @llvm.masked.load.nxv8i64(<vscale x 8 x i64> *%a, i32 1, <vscale x 8 x i1> %pg, <vscale x 8 x i64> undef)
   ret <vscale x 8 x i64> %load
 }
 
-declare <vscale x 32 x i8> @llvm.masked.load.nxv32i8(<vscale x 32 x i8>*, i32, <vscale x 32 x i1>, <vscale x 32 x i8>)
+define <vscale x 4 x i32> @masked_load_widen_3i32(<vscale x 3 x i32>* %a, <vscale x 4 x i1> %pg.wide) {
+; CHECK-LABEL: masked_load_widen_3i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    index z0.s, #0, #1
+; CHECK-NEXT:    mov z1.s, w8
+; CHECK-NEXT:    ptrue p1.s
+; CHECK-NEXT:    cmphi p2.s, p1/z, z1.s, z0.s
+; CHECK-NEXT:    and p0.b, p1/z, p2.b, p0.b
+; CHECK-NEXT:    ld1w { z0.s }, p0/z, [x0]
+; CHECK-NEXT:    ret
+  %pg = call <vscale x 3 x i1> @llvm.experimental.vector.extract.nxv3i1.nxv4i1(<vscale x 4 x i1> %pg.wide, i64 0)
+  %load = call <vscale x 3 x i32> @llvm.masked.load.nxv3i32(<vscale x 3 x i32> *%a, i32 1, <vscale x 3 x i1> %pg, <vscale x 3 x i32> undef)
+  %r = call <vscale x 4 x i32> @llvm.experimental.vector.insert.nxv4i32.nxv3i32(<vscale x 4 x i32> undef, <vscale x 3 x i32> %load, i64 0)
+  ret <vscale x 4 x i32> %r
+}
+
+define <vscale x 8 x i32> @masked_load_widen_7i32(<vscale x 7 x i32>* %a, <vscale x 8 x i1> %pg.wide) {
+; CHECK-LABEL: masked_load_widen_7i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    mov z1.s, w8
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    ptrue p1.s
+; CHECK-NEXT:    index z0.s, #0, #1
+; CHECK-NEXT:    mov z2.s, w8
+; CHECK-NEXT:    cmphi p2.s, p1/z, z1.s, z0.s
+; CHECK-NEXT:    add z0.s, z0.s, z2.s
+; CHECK-NEXT:    cmphi p1.s, p1/z, z1.s, z0.s
+; CHECK-NEXT:    uzp1 p1.h, p2.h, p1.h
+; CHECK-NEXT:    ptrue p2.h
+; CHECK-NEXT:    and p0.b, p2/z, p1.b, p0.b
+; CHECK-NEXT:    pfalse p1.b
+; CHECK-NEXT:    zip1 p2.h, p0.h, p1.h
+; CHECK-NEXT:    zip2 p0.h, p0.h, p1.h
+; CHECK-NEXT:    ld1w { z0.s }, p2/z, [x0]
+; CHECK-NEXT:    ld1w { z1.s }, p0/z, [x0, #1, mul vl]
+; CHECK-NEXT:    ret
+  %pg = call <vscale x 7 x i1> @llvm.experimental.vector.extract.nxv7i1.nxv8i1(<vscale x 8 x i1> %pg.wide, i64 0)
+  %load = call <vscale x 7 x i32> @llvm.masked.load.nxv7i32(<vscale x 7 x i32> *%a, i32 1, <vscale x 7 x i1> %pg, <vscale x 7 x i32> undef)
+  %r = call <vscale x 8 x i32> @llvm.experimental.vector.insert.nxv8i32.nxv7i32(<vscale x 8 x i32> undef, <vscale x 7 x i32> %load, i64 0)
+  ret <vscale x 8 x i32> %r
+}
+
 
-declare <vscale x 32 x i16> @llvm.masked.load.nxv32i16(<vscale x 32 x i16>*, i32, <vscale x 32 x i1>, <vscale x 32 x i16>)
 
+declare <vscale x 32 x i8> @llvm.masked.load.nxv32i8(<vscale x 32 x i8>*, i32, <vscale x 32 x i1>, <vscale x 32 x i8>)
+declare <vscale x 32 x i16> @llvm.masked.load.nxv32i16(<vscale x 32 x i16>*, i32, <vscale x 32 x i1>, <vscale x 32 x i16>)
 declare <vscale x 2 x i32> @llvm.masked.load.nxv2i32(<vscale x 2 x i32>*, i32, <vscale x 2 x i1>, <vscale x 2 x i32>)
+declare <vscale x 3 x i32> @llvm.masked.load.nxv3i32(<vscale x 3 x i32>*, i32, <vscale x 3 x i1>, <vscale x 3 x i32>)
+declare <vscale x 7 x i32> @llvm.masked.load.nxv7i32(<vscale x 7 x i32>*, i32, <vscale x 7 x i1>, <vscale x 7 x i32>)
 declare <vscale x 8 x i32> @llvm.masked.load.nxv8i32(<vscale x 8 x i32>*, i32, <vscale x 8 x i1>, <vscale x 8 x i32>)
-
 declare <vscale x 8 x i64> @llvm.masked.load.nxv8i64(<vscale x 8 x i64>*, i32, <vscale x 8 x i1>, <vscale x 8 x i64>)
+declare <vscale x 4 x i32> @llvm.experimental.vector.insert.nxv4i32.nxv3i32(<vscale x 4 x i32>, <vscale x 3 x i32>, i64)
+declare <vscale x 8 x i32> @llvm.experimental.vector.insert.nxv8i32.nxv7i32(<vscale x 8 x i32>, <vscale x 7 x i32>, i64)
+declare <vscale x 3 x i1> @llvm.experimental.vector.extract.nxv3i1.nxv4i1(<vscale x 4 x i1>, i64)
+declare <vscale x 7 x i1> @llvm.experimental.vector.extract.nxv7i1.nxv8i1(<vscale x 8 x i1>, i64)