[CodeGen] Add hooks/combine to form vector extloads, and enable it on X86.

[ab]

Summary

Moved from the ML:

As the last change in my extload series, here are 3 squashed (WIP) patches
to actually form extloads on vector types.
They used to be disabled, because "None of the supported targets knows
how to perform load and sign extend on vectors in one instruction."

The first part enables the combine on legal vectors, but hides it
behind a profitability callback.
For instance, on ARM, several instructions have folded extload forms,
so it's not always beneficial to create an extload node (and trying to
match extloads is a whole 'nother can of worms).

The second part adds a combine to fold s/zextloads of illegal
(splittable) vector types, to replace it directly by multiple smaller
extloads. I'm not a big fan of this kind of pseudo-legalization in
combines. However, I tried the alternative: form illegal extloads, and
later try to split them up, but then, you sometimes generate extloads
that can't be split up, but have a valid ext+load expansion. At
vector-op legalization time, it's too late to generate this kind of
thing, so you end up forced to scalarize. It's better to just avoid
creating egregiously illegal nodes.

Finally, the last part enables this all, unconditionally, on X86.

Note that the splitting combine is happy with "custom" extloads. As
is, this bypasses the actual custom lowering, and just unrolls the
extload. But from what I've seen, this is still much better than the
current custom lowering, which does some kind of unrolling at the end
anyway (see for instance load_sext_4i8_to_4i64 on SSE2, and the added
FIXME).

Also note that there's a regression in widen_load-2.ll, where
we can no longer fold the load. I'll look into that later.

Anyway: as can be seen from the nice testcase cleanups, there's
something to be done here. The combines feel a bit dirty, but I don't
see a better alternative. Finally, I didn't see changes on the
testsuite (SSE2 X86-64, I'll try SSE4.1 and AVX2 as well.)

P.S.: I squashed all three because I don't think it makes it harder to
review, just longer. The three changes are nicely isolated, and will
be committed separately. I'll split into 3 threads if desired.

Depends on D6533.

Thanks,
-Ahmed

[arsenm]

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

5525–5526

I don't think this will work correctly for 3 vectors, but it probably doesn't matter

5527

This should use .getStoreSize()

5805–5816

This looks like the same in the sextload handling. Should probably be moved to a new function

5822

This should also use getStoreSize()

5828–5832

It might be helpful to add a new version of getExtLoad based on the version that takes the MMO and an offset rather than having to pass all of the separate arguments

lib/Target/X86/X86ISelLowering.cpp

20210

Missing override

[chandlerc]

Wow this looks amazing. I'm glad you were able to make it all the way through to fixing this properly (I wasn't when I looked here, I ran away screaming).

Some comments inline...

include/llvm/Target/TargetLowering.h

1521

Do we you "ExtLd" in APIs elsewhere? this kind of extreme abbreviation, especially if deviating from other abbreviations, makes the APIs really hard to understand and find.

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

5794

This code is extremely similar to the sext case. Can it be factored out with an appropriate predicate or input instruction tag or something?

5799–5805

Even if you can't put this into a common function with sext, at least pull both into their own functions so that you can use early exit for all of this rather than boolean variables.

test/CodeGen/X86/widen_load-2.ll

76–79 ↗

(On Diff #17942)

This is both weird and unfortunate... Do understand why this happens?

[ab]

include/llvm/Target/TargetLowering.h

1521

I agree, and originally wanted to use the closer-to-ubiquitous LoadExt. However, there's enableExtLdPromotion, which is the most similar API so should be similarly named.

I guess I could rename both to LoadExt instead, how does that sound? That would stay consistent with ISD::LoadExtType, and the various *LoadExt* legality functions.

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

5525–5526

You're right, I added a check for isPow2VectorType.

5794

It should be trivial to factor it out. Other similar combines as well (I'll take care of it separately.)

5828–5832

I thought so as well, but two things would make it confusing IMO: 1) the offset operand is for indexed loads only, which is a concept different from an ADDed base pointer. Also, less importantly, 2) we're not sure we can reuse the previous MMO, as the types may differ.
Or maybe you meant something else?

test/CodeGen/X86/widen_load-2.ll

76–79 ↗

(On Diff #17942)

This was actually a rebasing mistake, and doesn't happen on a clean apply of the patch. Sorry for the noise.

[chandlerc]

include/llvm/Target/TargetLowering.h

1521

We're so inconsistent here that I don't really care about what the old code happened to name things provided we're consistent going forward and converge on that. Given that, I'd prefer the minimal amount of abbreviation that is sane, and I think spelling out "load" but abbreviating "ext" is a fine compromise there.

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

5794

Please don't add duplicated code and then factor it afterward.

Either do the minimal amount of factoring in this change so that we don't have to review 2x the code, or do the factoring first, and then the functional change.

[ab]

Ping!

-Ahmed

[hfinkel]

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

5227

Please make this comment more verbose. We might generate multiple loads and then combine them together, and it is not clear here whether this combining happens to the results of the sext or the sext's operand.

5274

Is this alignment correct? Aren't these loads smaller than the original one?

[chandlerc]

My only comments beyond what Hal has already mentioned are real nits:

s/dl/DL/

Can you use DL everywhere? It's odd that in one place you use SDLoc(N0). It may be correct, but if so, it's likely not obvious to the reader why we need to do something different here.

Finally, I'd find the indentation more consistent with clang-format. But now we're waaay down into minor details. This is generally looking much better.

[ab]

• Use smaller alignment for the split loads.
• Improve formatting, names.
• Don't accept ANYEXTs, since it's not testable or supported yet.

[hfinkel]

LGTM.

include/llvm/Target/TargetLowering.h

public:
   /// Return true if zero-extending the specific node Val to type VT2 is free
   /// (either because it's implicitly zero-extended such as ARM ldrb / ldrh or
   /// because it's folded such as X86 zero-extending loads).
   virtual bool isZExtFree(SDValue Val, EVT VT2) const {
     return isZExtFree(Val.getValueType(), VT2);
   }
 
   /// Return true if an fpext operation is free (for instance, because
   /// single-precision floating-point numbers are implicitly extended to
   /// double-precision).
   virtual bool isFPExtFree(EVT VT) const {
     assert(VT.isFloatingPoint());
     return false;
   }
 
+  /// Return true if folding a vector load into ExtVal (a sign, zero, or any
+  /// extend node) is profitable.
+  virtual bool isVectorLoadExtDesirable(SDValue ExtVal) const { return false; }
+
   /// Return true if an fneg operation is free to the point where it is never
   /// worthwhile to replace it with a bitwise operation.
   virtual bool isFNegFree(EVT VT) const {
     assert(VT.isFloatingPoint());
     return false;
   }
 
   /// Return true if an fabs operation is free to the point where it is never

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

private:
 
     bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS,
                            SDValue &CC) const;
     bool isOneUseSetCC(SDValue N) const;
 
     SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
                                          unsigned HiOp);
     SDValue CombineConsecutiveLoads(SDNode *N, EVT VT);
+    SDValue CombineExtLoad(SDNode *N);
     SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT);
     SDValue BuildSDIV(SDNode *N);
     SDValue BuildSDIVPow2(SDNode *N);
     SDValue BuildUDIV(SDNode *N);
     SDValue BuildReciprocalEstimate(SDValue Op);
     SDValue BuildRsqrtEstimate(SDValue Op);
     SDValue BuildRsqrtNROneConst(SDValue Op, SDValue Est, unsigned Iterations);
     SDValue BuildRsqrtNRTwoConst(SDValue Op, SDValue Est, unsigned Iterations);
else
       Elts.push_back(DAG.getConstant(C.shl(ShAmt).lshr(ShAmt).getZExtValue(),
                                      SVT));
   }
 
   return DAG.getNode(ISD::BUILD_VECTOR, DL, VT, Elts).getNode();
 }
 
 // ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this:
 // "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))"
 // transformation. Returns true if extension are possible and the above
 // mentioned transformation is profitable.
 static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0,
                                     unsigned ExtOpc,
                                     SmallVectorImpl<SDNode *> &ExtendNodes,
                                     const TargetLowering &TLI) {
   bool HasCopyToRegUses = false;
   bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType());
if (!isTruncFree)
       return false;
     // Remember if this value is live-out.
     if (User->getOpcode() == ISD::CopyToReg)
       HasCopyToRegUses = true;
   }
 
   if (HasCopyToRegUses) {
     bool BothLiveOut = false;
     for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
          UI != UE; ++UI) {
       SDUse &Use = UI.getUse();
       if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) {
         BothLiveOut = true;
         break;
       }
     }
     if (BothLiveOut)
for (unsigned j = 0; j != 2; ++j) {
         Ops.push_back(DAG.getNode(ExtType, DL, ExtLoad->getValueType(0), SOp));
     }
 
     Ops.push_back(SetCC->getOperand(2));
     CombineTo(SetCC, DAG.getNode(ISD::SETCC, DL, SetCC->getValueType(0), Ops));
   }
 }
 
+// FIXME: Bring more similar combines here, common to sext/zext (maybe aext?).
+SDValue DAGCombiner::CombineExtLoad(SDNode *N) {
+  SDValue N0 = N->getOperand(0);
+  EVT DstVT = N->getValueType(0);
+  EVT SrcVT = N0.getValueType();
+
+  assert((N->getOpcode() == ISD::SIGN_EXTEND ||
+          N->getOpcode() == ISD::ZERO_EXTEND) &&
+         "Unexpected node type (not an extend)!");
+
+  // fold (sext (load x)) to multiple smaller sextloads; same for zext.
+  // For example, on a target with legal v4i32, but illegal v8i32, turn:
+  //   (v8i32 (sext (v8i16 (load x))))
+  // into:
+  //   (v8i32 (concat_vectors (v4i32 (sextload x)),
+  //                          (v4i32 (sextload (x + 16)))))
+  // Where uses of the original load, i.e.:
+  //   (v8i16 (load x))
+  // are replaced with:
+  //   (v8i16 (truncate
+  //     (v8i32 (concat_vectors (v4i32 (sextload x)),
+  //                            (v4i32 (sextload (x + 16)))))))
+  //
+  // This combine is only applicable to illegal, but splittable, vectors.
+  // All legal types, and illegal non-vector types, are handled elsewhere.
+  // This combine is controlled by TargetLowering::isVectorLoadExtDesirable.
+  //
+  if (N0->getOpcode() != ISD::LOAD)
+    return SDValue();
+
+  LoadSDNode *LN0 = cast<LoadSDNode>(N0);
+
+  if (!ISD::isNON_EXTLoad(LN0) || !ISD::isUNINDEXEDLoad(LN0) ||
+      !N0.hasOneUse() || LN0->isVolatile() || !DstVT.isVector() ||
+      !DstVT.isPow2VectorType() || !TLI.isVectorLoadExtDesirable(SDValue(N, 0)))
+    return SDValue();
+
+  SmallVector<SDNode *, 4> SetCCs;
+  if (!ExtendUsesToFormExtLoad(N, N0, N->getOpcode(), SetCCs, TLI))
+    return SDValue();
+
+  ISD::LoadExtType ExtType =
+      N->getOpcode() == ISD::SIGN_EXTEND ? ISD::SEXTLOAD : ISD::ZEXTLOAD;
+
+  // Try to split the vector types to get down to legal types.
+  EVT SplitSrcVT = SrcVT;
+  EVT SplitDstVT = DstVT;
+  while (!TLI.isLoadExtLegalOrCustom(ExtType, SplitDstVT, SplitSrcVT) &&
+         SplitSrcVT.getVectorNumElements() > 1) {
+    SplitDstVT = DAG.GetSplitDestVTs(SplitDstVT).first;
+    SplitSrcVT = DAG.GetSplitDestVTs(SplitSrcVT).first;
+  }
+
+  if (!TLI.isLoadExtLegalOrCustom(ExtType, SplitDstVT, SplitSrcVT))
+    return SDValue();
+
+  SDLoc DL(N);
+  const unsigned NumSplits =
+      DstVT.getVectorNumElements() / SplitDstVT.getVectorNumElements();
+  const unsigned Stride = SplitSrcVT.getStoreSize();
+  SmallVector<SDValue, 4> Loads;
+  SmallVector<SDValue, 4> Chains;
+
+  SDValue BasePtr = LN0->getBasePtr();
+  for (unsigned Idx = 0; Idx < NumSplits; Idx++) {
+    const unsigned Offset = Idx * Stride;
+    const unsigned Align = MinAlign(LN0->getAlignment(), Offset);
+
+    SDValue SplitLoad = DAG.getExtLoad(
+        ExtType, DL, SplitDstVT, LN0->getChain(), BasePtr,
+        LN0->getPointerInfo().getWithOffset(Offset), SplitSrcVT,
+        LN0->isVolatile(), LN0->isNonTemporal(), LN0->isInvariant(),
+        Align, LN0->getAAInfo());
+
+    BasePtr = DAG.getNode(ISD::ADD, DL, BasePtr.getValueType(), BasePtr,
+                          DAG.getConstant(Stride, BasePtr.getValueType()));
+
+    Loads.push_back(SplitLoad.getValue(0));
+    Chains.push_back(SplitLoad.getValue(1));
+  }
+
+  SDValue NewChain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chains);
+  SDValue NewValue = DAG.getNode(ISD::CONCAT_VECTORS, DL, DstVT, Loads);
+
+  CombineTo(N, NewValue);
+
+  // Replace uses of the original load (before extension)
+  // with a truncate of the concatenated sextloaded vectors.
+  SDValue Trunc =
+      DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), NewValue);
+  CombineTo(N0.getNode(), Trunc, NewChain);
+  ExtendSetCCUses(SetCCs, Trunc, NewValue, DL,
+                  (ISD::NodeType)N->getOpcode());
+  return SDValue(N, 0); // Return N so it doesn't get rechecked!
+}
+
 SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
   SDValue N0 = N->getOperand(0);
   EVT VT = N->getValueType(0);
 
   if (SDNode *Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
                                               LegalOperations))
     return SDValue(Res, 0);
 
if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG,
       else if (OpBits > DestBits)
         Op = DAG.getNode(ISD::TRUNCATE, SDLoc(N0), VT, Op);
       return DAG.getNode(ISD::SIGN_EXTEND_INREG, SDLoc(N), VT, Op,
                          DAG.getValueType(N0.getValueType()));
     }
   }
 
   // fold (sext (load x)) -> (sext (truncate (sextload x)))
-  // None of the supported targets knows how to perform load and sign extend
-  // on vectors in one instruction.  We only perform this transformation on
-  // scalars.
-  if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
-      ISD::isUNINDEXEDLoad(N0.getNode()) &&
-      ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
+  if (ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
+      ((!LegalOperations && !VT.isVector() &&
+        !cast<LoadSDNode>(N0)->isVolatile()) ||
        TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, N0.getValueType()))) {
     bool DoXform = true;
     SmallVector<SDNode*, 4> SetCCs;
     if (!N0.hasOneUse())
       DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI);
+    if (VT.isVector())
+      DoXform &= TLI.isVectorLoadExtDesirable(SDValue(N, 0));
     if (DoXform) {
       LoadSDNode *LN0 = cast<LoadSDNode>(N0);
       SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, SDLoc(N), VT,
                                        LN0->getChain(),
                                        LN0->getBasePtr(), N0.getValueType(),
                                        LN0->getMemOperand());
       CombineTo(N, ExtLoad);
       SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(N0),
                                   N0.getValueType(), ExtLoad);
       CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
       ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N),
                       ISD::SIGN_EXTEND);
       return SDValue(N, 0);   // Return N so it doesn't get rechecked!
     }
   }
 
+  // fold (sext (load x)) to multiple smaller sextloads.
+  // Only for illegal but splittable vectors.
+  if (SDValue ExtLoad = CombineExtLoad(N))
+    return ExtLoad;
+
   // fold (sext (sextload x)) -> (sext (truncate (sextload x)))
   // fold (sext ( extload x)) -> (sext (truncate (sextload x)))
   if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
       ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
     LoadSDNode *LN0 = cast<LoadSDNode>(N0);
     EVT MemVT = LN0->getMemoryVT();
     if ((!LegalOperations && !LN0->isVolatile()) ||
         TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, MemVT)) {
       SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, SDLoc(N), VT,
                                        LN0->getChain(),
                                        LN0->getBasePtr(), MemVT,
                                        LN0->getMemOperand());
       CombineTo(N, ExtLoad);
       CombineTo(N0.getNode(),
                 DAG.getNode(ISD::TRUNCATE, SDLoc(N0),
                             N0.getValueType(), ExtLoad),
                 ExtLoad.getValue(1));
       return SDValue(N, 0);   // Return N so it doesn't get rechecked!
     }
   }
 
   // fold (sext (and/or/xor (load x), cst)) ->
   //      (and/or/xor (sextload x), (sext cst))
   if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR ||
        N0.getOpcode() == ISD::XOR) &&
       isa<LoadSDNode>(N0.getOperand(0)) &&
       N0.getOperand(1).getOpcode() == ISD::Constant &&
       TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, N0.getValueType()) &&
       (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) {
     LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0));
     if (LN0->getExtensionType() != ISD::ZEXTLOAD && LN0->isUnindexed()) {
       bool DoXform = true;
if (N0.getOpcode() == ISD::AND &&
     }
     APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
     Mask = Mask.zext(VT.getSizeInBits());
     return DAG.getNode(ISD::AND, SDLoc(N), VT,
                        X, DAG.getConstant(Mask, VT));
   }
 
   // fold (zext (load x)) -> (zext (truncate (zextload x)))
-  // None of the supported targets knows how to perform load and vector_zext
-  // on vectors in one instruction.  We only perform this transformation on
-  // scalars.
-  if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
-      ISD::isUNINDEXEDLoad(N0.getNode()) &&
-      ((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
+  if (ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
+      ((!LegalOperations && !VT.isVector() &&
+        !cast<LoadSDNode>(N0)->isVolatile()) ||
        TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, N0.getValueType()))) {
     bool DoXform = true;
     SmallVector<SDNode*, 4> SetCCs;
     if (!N0.hasOneUse())
       DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI);
+    if (VT.isVector())
+      DoXform &= TLI.isVectorLoadExtDesirable(SDValue(N, 0));
     if (DoXform) {
       LoadSDNode *LN0 = cast<LoadSDNode>(N0);
       SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, SDLoc(N), VT,
                                        LN0->getChain(),
                                        LN0->getBasePtr(), N0.getValueType(),
                                        LN0->getMemOperand());
       CombineTo(N, ExtLoad);
       SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(N0),
                                   N0.getValueType(), ExtLoad);
       CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
 
       ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N),
                       ISD::ZERO_EXTEND);
       return SDValue(N, 0);   // Return N so it doesn't get rechecked!
     }
   }
 
+  // fold (zext (load x)) to multiple smaller zextloads.
+  // Only on illegal but splittable vectors.
+  if (SDValue ExtLoad = CombineExtLoad(N))
+    return ExtLoad;
+
   // fold (zext (and/or/xor (load x), cst)) ->
   //      (and/or/xor (zextload x), (zext cst))
   if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR ||
        N0.getOpcode() == ISD::XOR) &&
       isa<LoadSDNode>(N0.getOperand(0)) &&
       N0.getOperand(1).getOpcode() == ISD::Constant &&
       TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, N0.getValueType()) &&
       (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) {
     LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0));
     if (LN0->getExtensionType() != ISD::SEXTLOAD && LN0->isUnindexed()) {
       bool DoXform = true;
       SmallVector<SDNode*, 4> SetCCs;
       if (!N0.hasOneUse())
         DoXform = ExtendUsesToFormExtLoad(N, N0.getOperand(0), ISD::ZERO_EXTEND,
                                           SetCCs, TLI);
       if (DoXform) {
         SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, SDLoc(LN0), VT,
                                          LN0->getChain(), LN0->getBasePtr(),
                                          LN0->getMemoryVT(),
                                          LN0->getMemOperand());
         APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
         Mask = Mask.zext(VT.getSizeInBits());
         SDValue And = DAG.getNode(N0.getOpcode(), SDLoc(N), VT,
                                   ExtLoad, DAG.getConstant(Mask, VT));
         SDValue Trunc = DAG.getNode(ISD::TRUNCATE,
                                     SDLoc(N0.getOperand(0)),
                                     N0.getOperand(0).getValueType(), ExtLoad);
         CombineTo(N, And);
         CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1));
         ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N),
                         ISD::ZERO_EXTEND);
         return SDValue(N, 0);   // Return N so it doesn't get rechecked!
       }
     }
   }
 
   // fold (zext (zextload x)) -> (zext (truncate (zextload x)))
   // fold (zext ( extload x)) -> (zext (truncate (zextload x)))
   if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
       ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
     LoadSDNode *LN0 = cast<LoadSDNode>(N0);
     EVT MemVT = LN0->getMemoryVT();

lib/Target/X86/X86ISelLowering.h

public:
     /// virtual registers. Also, if isTruncateFree(Ty2, Ty1) is true, this
     /// does not necessarily apply to truncate instructions. e.g. on x86-64,
     /// all instructions that define 32-bit values implicit zero-extend the
     /// result out to 64 bits.
     bool isZExtFree(Type *Ty1, Type *Ty2) const override;
     bool isZExtFree(EVT VT1, EVT VT2) const override;
     bool isZExtFree(SDValue Val, EVT VT2) const override;
 
+    /// Return true if folding a vector load into ExtVal (a sign, zero, or any
+    /// extend node) is profitable.
+    bool isVectorLoadExtDesirable(SDValue) const override;
+
     /// Return true if an FMA operation is faster than a pair of fmul and fadd
     /// instructions. fmuladd intrinsics will be expanded to FMAs when this
     /// method returns true, otherwise fmuladd is expanded to fmul + fadd.
     bool isFMAFasterThanFMulAndFAdd(EVT VT) const override;
 
     /// Return true if it's profitable to narrow
     /// operations of type VT1 to VT2. e.g. on x86, it's profitable to narrow
     /// from i32 to i8 but not from i32 to i16.

lib/Target/X86/X86ISelLowering.cpp

static SDValue LowerSIGN_EXTEND(SDValue Op, const X86Subtarget *Subtarget,
 
   return DAG.getNode(ISD::CONCAT_VECTORS, dl, VT, OpLo, OpHi);
 }
 
 // Lower vector extended loads using a shuffle. If SSSE3 is not available we
 // may emit an illegal shuffle but the expansion is still better than scalar
 // code. We generate X86ISD::VSEXT for SEXTLOADs if it's available, otherwise
 // we'll emit a shuffle and a arithmetic shift.
+// FIXME: Is the expansion actually better than scalar code? It doesn't seem so.
 // TODO: It is possible to support ZExt by zeroing the undef values during
 // the shuffle phase or after the shuffle.
 static SDValue LowerExtendedLoad(SDValue Op, const X86Subtarget *Subtarget,
                                  SelectionDAG &DAG) {
   MVT RegVT = Op.getSimpleValueType();
   assert(RegVT.isVector() && "We only custom lower vector sext loads.");
   assert(RegVT.isInteger() &&
          "We only custom lower integer vector sext loads.");
bool X86TargetLowering::isZExtFree(SDValue Val, EVT VT2) const {
   case MVT::i32:
     // X86 has 8, 16, and 32-bit zero-extending loads.
     return true;
   }
 
   return false;
 }
 
+bool X86TargetLowering::isVectorLoadExtDesirable(SDValue) const { return true; }
+
 bool
 X86TargetLowering::isFMAFasterThanFMulAndFAdd(EVT VT) const {
   if (!(Subtarget->hasFMA() || Subtarget->hasFMA4()))
     return false;
 
   VT = VT.getScalarType();
 
   if (!VT.isSimple())

test/CodeGen/X86/vector-sext.ll

 ; X32-SSE41-NEXT:    retl
   %extmask = sext <4 x i1> %mask to <4 x i64>
   ret <4 x i64> %extmask
 }
 
 define <16 x i16> @sext_16i8_to_16i16(<16 x i8> *%ptr) {
 ; SSE2-LABEL: sext_16i8_to_16i16:
 ; SSE2:       # BB#0: # %entry
-; SSE2-NEXT:    movdqa (%rdi), %xmm1
-; SSE2-NEXT:    movdqa %xmm1, %xmm0
+; SSE2-NEXT:    movq (%rdi), %xmm0
 ; SSE2-NEXT:    punpcklbw {{.*#+}} xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
-; SSE2-NEXT:    psllw $8, %xmm0
 ; SSE2-NEXT:    psraw $8, %xmm0
-; SSE2-NEXT:    punpckhbw {{.*#+}} xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
-; SSE2-NEXT:    psllw $8, %xmm1
+; SSE2-NEXT:    movq 8(%rdi), %xmm1
+; SSE2-NEXT:    punpcklbw {{.*#+}} xmm1 = xmm1[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
 ; SSE2-NEXT:    psraw $8, %xmm1
 ; SSE2-NEXT:    retq
 ;
 ; SSSE3-LABEL: sext_16i8_to_16i16:
 ; SSSE3:       # BB#0: # %entry
-; SSSE3-NEXT:    movdqa (%rdi), %xmm1
-; SSSE3-NEXT:    movdqa %xmm1, %xmm0
+; SSSE3-NEXT:    movq (%rdi), %xmm0
 ; SSSE3-NEXT:    punpcklbw {{.*#+}} xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
-; SSSE3-NEXT:    psllw $8, %xmm0
 ; SSSE3-NEXT:    psraw $8, %xmm0
-; SSSE3-NEXT:    punpckhbw {{.*#+}} xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
-; SSSE3-NEXT:    psllw $8, %xmm1
+; SSSE3-NEXT:    movq 8(%rdi), %xmm1
+; SSSE3-NEXT:    punpcklbw {{.*#+}} xmm1 = xmm1[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
 ; SSSE3-NEXT:    psraw $8, %xmm1
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: sext_16i8_to_16i16:
 ; SSE41:       # BB#0: # %entry
-; SSE41-NEXT:    movdqa (%rdi), %xmm1
-; SSE41-NEXT:    pmovzxbw %xmm1, %xmm0
-; SSE41-NEXT:    psllw $8, %xmm0
-; SSE41-NEXT:    psraw $8, %xmm0
-; SSE41-NEXT:    punpckhbw {{.*#+}} xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
-; SSE41-NEXT:    psllw $8, %xmm1
-; SSE41-NEXT:    psraw $8, %xmm1
+; SSE41-NEXT:    pmovsxbw (%rdi), %xmm0
+; SSE41-NEXT:    pmovsxbw 8(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 ;
 ; AVX1-LABEL: sext_16i8_to_16i16:
 ; AVX1:       # BB#0: # %entry
-; AVX1-NEXT:    vmovdqa (%rdi), %xmm0
-; AVX1-NEXT:    vpmovsxbw %xmm0, %xmm1
-; AVX1-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[2,3,0,1]
-; AVX1-NEXT:    vpmovsxbw %xmm0, %xmm0
-; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
+; AVX1-NEXT:    vpmovsxbw (%rdi), %xmm0
+; AVX1-NEXT:    vpmovsxbw 8(%rdi), %xmm1
+; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: sext_16i8_to_16i16:
 ; AVX2:       # BB#0: # %entry
 ; AVX2-NEXT:    vpmovsxbw (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 ;
 ; X32-SSE41-LABEL: sext_16i8_to_16i16:
 ; X32-SSE41:       # BB#0: # %entry
 ; X32-SSE41-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X32-SSE41-NEXT:    movdqa (%eax), %xmm1
-; X32-SSE41-NEXT:    pmovzxbw %xmm1, %xmm0
-; X32-SSE41-NEXT:    psllw $8, %xmm0
-; X32-SSE41-NEXT:    psraw $8, %xmm0
-; X32-SSE41-NEXT:    punpckhbw {{.*#+}} xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
-; X32-SSE41-NEXT:    psllw $8, %xmm1
-; X32-SSE41-NEXT:    psraw $8, %xmm1
+; X32-SSE41-NEXT:    pmovsxbw (%eax), %xmm0
+; X32-SSE41-NEXT:    pmovsxbw 8(%eax), %xmm1
 ; X32-SSE41-NEXT:    retl
 entry:
  %X = load <16 x i8>* %ptr
  %Y = sext <16 x i8> %X to <16 x i16>
  ret <16 x i16> %Y
 }
 
 define <4 x i64> @sext_4i8_to_4i64(<4 x i8> %mask) {

 ; X32-SSE41-NEXT:    retl
   %extmask = sext <4 x i8> %mask to <4 x i64>
   ret <4 x i64> %extmask
 }
 
 define <4 x i64> @load_sext_4i8_to_4i64(<4 x i8> *%ptr) {
 ; SSE2-LABEL: load_sext_4i8_to_4i64:
 ; SSE2:       # BB#0: # %entry
-; SSE2-NEXT:    movd (%rdi), %xmm1
-; SSE2-NEXT:    punpcklbw {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3],xmm1[4],xmm0[4],xmm1[5],xmm0[5],xmm1[6],xmm0[6],xmm1[7],xmm0[7]
-; SSE2-NEXT:    punpcklwd {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[0,1,1,3]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movsbq %al, %rax
+; SSE2-NEXT:    movsbq 1(%rdi), %rax
+; SSE2-NEXT:    movd %rax, %xmm1
+; SSE2-NEXT:    movsbq (%rdi), %rax
 ; SSE2-NEXT:    movd %rax, %xmm0
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movsbq %al, %rax
-; SSE2-NEXT:    movd %rax, %xmm2
-; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movsbq %al, %rax
-; SSE2-NEXT:    movd %rax, %xmm1
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movsbq %al, %rax
+; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSE2-NEXT:    movsbq 3(%rdi), %rax
 ; SSE2-NEXT:    movd %rax, %xmm2
+; SSE2-NEXT:    movsbq 2(%rdi), %rax
+; SSE2-NEXT:    movd %rax, %xmm1
 ; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
 ; SSE2-NEXT:    retq
 ;
 ; SSSE3-LABEL: load_sext_4i8_to_4i64:
 ; SSSE3:       # BB#0: # %entry
-; SSSE3-NEXT:    movd (%rdi), %xmm1
-; SSSE3-NEXT:    punpcklbw {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3],xmm1[4],xmm0[4],xmm1[5],xmm0[5],xmm1[6],xmm0[6],xmm1[7],xmm0[7]
-; SSSE3-NEXT:    punpcklwd {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3]
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[0,1,1,3]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movsbq %al, %rax
+; SSSE3-NEXT:    movsbq 1(%rdi), %rax
+; SSSE3-NEXT:    movd %rax, %xmm1
+; SSSE3-NEXT:    movsbq (%rdi), %rax
 ; SSSE3-NEXT:    movd %rax, %xmm0
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movsbq %al, %rax
-; SSSE3-NEXT:    movd %rax, %xmm2
-; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movsbq %al, %rax
-; SSSE3-NEXT:    movd %rax, %xmm1
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movsbq %al, %rax
+; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSSE3-NEXT:    movsbq 3(%rdi), %rax
 ; SSSE3-NEXT:    movd %rax, %xmm2
+; SSSE3-NEXT:    movsbq 2(%rdi), %rax
+; SSSE3-NEXT:    movd %rax, %xmm1
 ; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: load_sext_4i8_to_4i64:
 ; SSE41:       # BB#0: # %entry
-; SSE41-NEXT:    pmovzxbd (%rdi), %xmm1
-; SSE41-NEXT:    pmovzxdq %xmm1, %xmm0
-; SSE41-NEXT:    pextrq $1, %xmm0, %rax
-; SSE41-NEXT:    movsbq %al, %rax
-; SSE41-NEXT:    movd %rax, %xmm2
-; SSE41-NEXT:    movd %xmm0, %rax
-; SSE41-NEXT:    movsbq %al, %rax
-; SSE41-NEXT:    movd %rax, %xmm0
-; SSE41-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSE41-NEXT:    pshufd {{.*#+}} xmm1 = xmm1[2,2,3,3]
-; SSE41-NEXT:    pextrq $1, %xmm1, %rax
-; SSE41-NEXT:    movsbq %al, %rax
-; SSE41-NEXT:    movd %rax, %xmm2
-; SSE41-NEXT:    movd %xmm1, %rax
-; SSE41-NEXT:    movsbq %al, %rax
-; SSE41-NEXT:    movd %rax, %xmm1
-; SSE41-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
+; SSE41-NEXT:    pmovsxbq (%rdi), %xmm0
+; SSE41-NEXT:    pmovsxbq 2(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 ;
 ; AVX1-LABEL: load_sext_4i8_to_4i64:
 ; AVX1:       # BB#0: # %entry
 ; AVX1-NEXT:    vpmovsxbd (%rdi), %xmm0
 ; AVX1-NEXT:    vpmovsxdq %xmm0, %xmm1
 ; AVX1-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[2,3,0,1]
 ; AVX1-NEXT:    vpmovsxdq %xmm0, %xmm0
 ; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: load_sext_4i8_to_4i64:
 ; AVX2:       # BB#0: # %entry
 ; AVX2-NEXT:    vpmovsxbq (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 ;
 ; X32-SSE41-LABEL: load_sext_4i8_to_4i64:
 ; X32-SSE41:       # BB#0: # %entry
 ; X32-SSE41-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X32-SSE41-NEXT:    movd (%eax), %xmm0
-; X32-SSE41-NEXT:    pmovzxbd %xmm0, %xmm1
-; X32-SSE41-NEXT:    pmovzxbq %xmm0, %xmm2
-; X32-SSE41-NEXT:    movd %xmm2, %eax
-; X32-SSE41-NEXT:    movsbl %al, %eax
-; X32-SSE41-NEXT:    movd %eax, %xmm0
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $1, %eax, %xmm0
-; X32-SSE41-NEXT:    pextrd $2, %xmm2, %eax
-; X32-SSE41-NEXT:    movsbl %al, %eax
-; X32-SSE41-NEXT:    pinsrd $2, %eax, %xmm0
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $3, %eax, %xmm0
-; X32-SSE41-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; X32-SSE41-NEXT:    movd %xmm2, %eax
-; X32-SSE41-NEXT:    movsbl %al, %eax
-; X32-SSE41-NEXT:    movd %eax, %xmm1
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $1, %eax, %xmm1
-; X32-SSE41-NEXT:    pextrd $2, %xmm2, %eax
-; X32-SSE41-NEXT:    movsbl %al, %eax
-; X32-SSE41-NEXT:    pinsrd $2, %eax, %xmm1
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $3, %eax, %xmm1
+; X32-SSE41-NEXT:    pmovsxbq (%eax), %xmm0
+; X32-SSE41-NEXT:    pmovsxbq 2(%eax), %xmm1
 ; X32-SSE41-NEXT:    retl
 entry:
  %X = load <4 x i8>* %ptr
  %Y = sext <4 x i8> %X to <4 x i64>
  ret <4 x i64>%Y
 }
 
 define <4 x i64> @load_sext_4i16_to_4i64(<4 x i16> *%ptr) {
 ; SSE2-LABEL: load_sext_4i16_to_4i64:
 ; SSE2:       # BB#0: # %entry
-; SSE2-NEXT:    movq (%rdi), %xmm1
-; SSE2-NEXT:    punpcklwd {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[0,1,1,3]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movswq %ax, %rax
+; SSE2-NEXT:    movswq 2(%rdi), %rax
+; SSE2-NEXT:    movd %rax, %xmm1
+; SSE2-NEXT:    movswq (%rdi), %rax
 ; SSE2-NEXT:    movd %rax, %xmm0
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movswq %ax, %rax
-; SSE2-NEXT:    movd %rax, %xmm2
-; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movswq %ax, %rax
-; SSE2-NEXT:    movd %rax, %xmm1
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSE2-NEXT:    movd %xmm2, %rax
-; SSE2-NEXT:    movswq %ax, %rax
+; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSE2-NEXT:    movswq 6(%rdi), %rax
 ; SSE2-NEXT:    movd %rax, %xmm2
+; SSE2-NEXT:    movswq 4(%rdi), %rax
+; SSE2-NEXT:    movd %rax, %xmm1
 ; SSE2-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
 ; SSE2-NEXT:    retq
 ;
 ; SSSE3-LABEL: load_sext_4i16_to_4i64:
 ; SSSE3:       # BB#0: # %entry
-; SSSE3-NEXT:    movq (%rdi), %xmm1
-; SSSE3-NEXT:    punpcklwd {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3]
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[0,1,1,3]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movswq %ax, %rax
+; SSSE3-NEXT:    movswq 2(%rdi), %rax
+; SSSE3-NEXT:    movd %rax, %xmm1
+; SSSE3-NEXT:    movswq (%rdi), %rax
 ; SSSE3-NEXT:    movd %rax, %xmm0
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movswq %ax, %rax
-; SSSE3-NEXT:    movd %rax, %xmm2
-; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movswq %ax, %rax
-; SSSE3-NEXT:    movd %rax, %xmm1
-; SSSE3-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
-; SSSE3-NEXT:    movd %xmm2, %rax
-; SSSE3-NEXT:    movswq %ax, %rax
+; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
+; SSSE3-NEXT:    movswq 6(%rdi), %rax
 ; SSSE3-NEXT:    movd %rax, %xmm2
+; SSSE3-NEXT:    movswq 4(%rdi), %rax
+; SSSE3-NEXT:    movd %rax, %xmm1
 ; SSSE3-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: load_sext_4i16_to_4i64:
 ; SSE41:       # BB#0: # %entry
-; SSE41-NEXT:    movq (%rdi), %xmm0
-; SSE41-NEXT:    pmovzxwd %xmm0, %xmm1
-; SSE41-NEXT:    pmovzxwq %xmm0, %xmm0
-; SSE41-NEXT:    pextrq $1, %xmm0, %rax
-; SSE41-NEXT:    movswq %ax, %rax
-; SSE41-NEXT:    movd %rax, %xmm2
-; SSE41-NEXT:    movd %xmm0, %rax
-; SSE41-NEXT:    movswq %ax, %rax
-; SSE41-NEXT:    movd %rax, %xmm0
-; SSE41-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm2[0]
-; SSE41-NEXT:    pshufd {{.*#+}} xmm1 = xmm1[2,2,3,3]
-; SSE41-NEXT:    pextrq $1, %xmm1, %rax
-; SSE41-NEXT:    movswq %ax, %rax
-; SSE41-NEXT:    movd %rax, %xmm2
-; SSE41-NEXT:    movd %xmm1, %rax
-; SSE41-NEXT:    movswq %ax, %rax
-; SSE41-NEXT:    movd %rax, %xmm1
-; SSE41-NEXT:    punpcklqdq {{.*#+}} xmm1 = xmm1[0],xmm2[0]
+; SSE41-NEXT:    pmovsxwq (%rdi), %xmm0
+; SSE41-NEXT:    pmovsxwq 4(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 ;
 ; AVX1-LABEL: load_sext_4i16_to_4i64:
 ; AVX1:       # BB#0: # %entry
 ; AVX1-NEXT:    vpmovsxwd (%rdi), %xmm0
 ; AVX1-NEXT:    vpmovsxdq %xmm0, %xmm1
 ; AVX1-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[2,3,0,1]
 ; AVX1-NEXT:    vpmovsxdq %xmm0, %xmm0
 ; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: load_sext_4i16_to_4i64:
 ; AVX2:       # BB#0: # %entry
 ; AVX2-NEXT:    vpmovsxwq (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 ;
 ; X32-SSE41-LABEL: load_sext_4i16_to_4i64:
 ; X32-SSE41:       # BB#0: # %entry
 ; X32-SSE41-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X32-SSE41-NEXT:    movsd (%eax), %xmm0
-; X32-SSE41-NEXT:    pmovzxwd %xmm0, %xmm1
-; X32-SSE41-NEXT:    pmovzxwq %xmm0, %xmm2
-; X32-SSE41-NEXT:    movd %xmm2, %eax
-; X32-SSE41-NEXT:    cwtl
-; X32-SSE41-NEXT:    movd %eax, %xmm0
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $1, %eax, %xmm0
-; X32-SSE41-NEXT:    pextrd $2, %xmm2, %eax
-; X32-SSE41-NEXT:    cwtl
-; X32-SSE41-NEXT:    pinsrd $2, %eax, %xmm0
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $3, %eax, %xmm0
-; X32-SSE41-NEXT:    pshufd {{.*#+}} xmm2 = xmm1[2,2,3,3]
-; X32-SSE41-NEXT:    movd %xmm2, %eax
-; X32-SSE41-NEXT:    cwtl
-; X32-SSE41-NEXT:    movd %eax, %xmm1
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $1, %eax, %xmm1
-; X32-SSE41-NEXT:    pextrd $2, %xmm2, %eax
-; X32-SSE41-NEXT:    cwtl
-; X32-SSE41-NEXT:    pinsrd $2, %eax, %xmm1
-; X32-SSE41-NEXT:    sarl $31, %eax
-; X32-SSE41-NEXT:    pinsrd $3, %eax, %xmm1
+; X32-SSE41-NEXT:    pmovsxwq (%eax), %xmm0
+; X32-SSE41-NEXT:    pmovsxwq 4(%eax), %xmm1
 ; X32-SSE41-NEXT:    retl
 entry:
  %X = load <4 x i16>* %ptr
  %Y = sext <4 x i16> %X to <4 x i64>
  ret <4 x i64>%Y
 }

test/CodeGen/X86/vector-zext.ll

 ; SSSE3-NEXT:   movdqa {{.*#+}} xmm2 = [255,255,255,255,255,255,255,255]
 ; SSSE3-NEXT:   pand %xmm2, %xmm0
 ; SSSE3-NEXT:   punpckhbw %xmm1, %xmm1 # xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
 ; SSSE3-NEXT:   pand %xmm2, %xmm1
 ; SSSE3-NEXT:   retq
 
 ; SSE41-LABEL: load_zext_16i8_to_16i16:
 ; SSE41:        # BB#0: # %entry
-; SSE41-NEXT:    movdqa (%rdi), %xmm1
-; SSE41-NEXT:    pmovzxbw %xmm1, %xmm0
-; SSE41-NEXT:    movdqa {{.*#+}} xmm2 = [255,255,255,255,255,255,255,255]
-; SSE41-NEXT:    pand %xmm2, %xmm0
-; SSE41-NEXT:    punpckhbw %xmm1, %xmm1 # xmm1 = xmm1[8,8,9,9,10,10,11,11,12,12,13,13,14,14,15,15]
-; SSE41-NEXT:    pand %xmm2, %xmm1
+; SSE41-NEXT:    pmovzxbw (%rdi), %xmm0
+; SSE41-NEXT:    pmovzxbw 8(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 
 ; AVX1-LABEL: load_zext_16i8_to_16i16:
 ; AVX1:        # BB#0: # %entry
-; AVX1-NEXT:    vmovdqa (%rdi), %xmm0
-; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT:    vpunpckhbw %xmm1, %xmm0, %xmm1 # xmm1 = xmm0[8],xmm1[8],xmm0[9],xmm1[9],xmm0[10],xmm1[10],xmm0[11],xmm1[11],xmm0[12],xmm1[12],xmm0[13],xmm1[13],xmm0[14],xmm1[14],xmm0[15],xmm1[15]
-; AVX1-NEXT:    vpmovzxbw %xmm0, %xmm0
+; AVX1-NEXT:    vpmovzxbw (%rdi), %xmm0
+; AVX1-NEXT:    vpmovzxbw 8(%rdi), %xmm1
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; AVX1-NEXT:    retq
 
 ; AVX2-LABEL: load_zext_16i8_to_16i16:
 ; AVX2:        # BB#0: # %entry
 ; AVX2-NEXT:    vpmovzxbw (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 entry:

 ; SSSE3-NEXT:   movdqa {{.*#+}} xmm2 = [65535,65535,65535,65535]
 ; SSSE3-NEXT:   pand %xmm2, %xmm0
 ; SSSE3-NEXT:   punpckhwd %xmm1, %xmm1 # xmm1 = xmm1[4,4,5,5,6,6,7,7]
 ; SSSE3-NEXT:   pand %xmm2, %xmm1
 ; SSSE3-NEXT:   retq
 
 ; SSE41-LABEL: load_zext_8i16_to_8i32:
 ; SSE41:        # BB#0: # %entry
-; SSE41-NEXT:    movdqa (%rdi), %xmm1
-; SSE41-NEXT:    pmovzxwd %xmm1, %xmm0
-; SSE41-NEXT:    movdqa {{.*#+}} xmm2 = [65535,65535,65535,65535]
-; SSE41-NEXT:    pand %xmm2, %xmm0
-; SSE41-NEXT:    punpckhwd %xmm1, %xmm1 # xmm1 = xmm1[4,4,5,5,6,6,7,7]
-; SSE41-NEXT:    pand %xmm2, %xmm1
+; SSE41-NEXT:    pmovzxwd (%rdi), %xmm0
+; SSE41-NEXT:    pmovzxwd 8(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 
 ; AVX1-LABEL: load_zext_8i16_to_8i32:
 ; AVX1:        # BB#0: # %entry
-; AVX1-NEXT:    vmovdqa (%rdi), %xmm0
-; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT:    vpunpckhwd %xmm1, %xmm0, %xmm1 # xmm1 = xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
-; AVX1-NEXT:    vpmovzxwd %xmm0, %xmm0
+; AVX1-NEXT:    vpmovzxwd (%rdi), %xmm0
+; AVX1-NEXT:    vpmovzxwd 8(%rdi), %xmm1
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; AVX1-NEXT:    retq
 
 ; AVX2-LABEL: load_zext_8i16_to_8i32:
 ; AVX2:        # BB#0: # %entry
 ; AVX2-NEXT:    vpmovzxwd (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 entry:

 ; SSSE3-NEXT:   movdqa {{.*#+}} xmm2 = [4294967295,4294967295]
 ; SSSE3-NEXT:   pand %xmm2, %xmm0
 ; SSSE3-NEXT:   pshufd $250, %xmm1, %xmm1 # xmm1 = xmm1[2,2,3,3]
 ; SSSE3-NEXT:   pand %xmm2, %xmm1
 ; SSSE3-NEXT:   retq
 
 ; SSE41-LABEL: load_zext_4i32_to_4i64:
 ; SSE41:        # BB#0: # %entry
-; SSE41-NEXT:    movdqa (%rdi), %xmm1
-; SSE41-NEXT:    pmovzxdq %xmm1, %xmm0
-; SSE41-NEXT:    movdqa {{.*#+}} xmm2 = [4294967295,4294967295]
-; SSE41-NEXT:    pand %xmm2, %xmm0
-; SSE41-NEXT:    pshufd $250, %xmm1, %xmm1 # xmm1 = xmm1[2,2,3,3]
-; SSE41-NEXT:    pand %xmm2, %xmm1
+; SSE41-NEXT:    pmovzxdq (%rdi), %xmm0
+; SSE41-NEXT:    pmovzxdq 8(%rdi), %xmm1
 ; SSE41-NEXT:    retq
 
 ; AVX1-LABEL: load_zext_4i32_to_4i64:
 ; AVX1:        # BB#0: # %entry
-; AVX1-NEXT:    vmovdqa (%rdi), %xmm0
-; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT:    vpunpckhdq %xmm1, %xmm0, %xmm1 # xmm1 = xmm0[2],xmm1[2],xmm0[3],xmm1[3]
-; AVX1-NEXT:    vpmovzxdq %xmm0, %xmm0
+; AVX1-NEXT:    vpmovzxdq (%rdi), %xmm0
+; AVX1-NEXT:    vpmovzxdq 8(%rdi), %xmm1
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; AVX1-NEXT:    retq
 
 ; AVX2-LABEL: load_zext_4i32_to_4i64:
 ; AVX2:        # BB#0: # %entry
 ; AVX2-NEXT:    vpmovzxdq (%rdi), %ymm0
 ; AVX2-NEXT:    retq
 entry:
  %X = load <4 x i32>* %ptr
  %Y = zext <4 x i32> %X to <4 x i64>
  ret <4 x i64>%Y
 }