[X86][SSE] Attempt to match OP(SHUFFLE(X,Y),SHUFFLE(X,Y)) -> SHUFFLE(HOP(X,Y))

[RKSimon]

Summary

An initial backend patch towards fixing the various poor HADD combines (PR34724, PR41813, PR45747 etc.).

This extends isHorizontalBinOp to check if we have per-element horizontal ops (odd+even element pairs), but not in the expected serial order - in which case we build a "post shuffle mask" that we can apply to the HOP result, assuming we have fast-hops/optsize etc.

The next step will be to extend the SHUFFLE(HOP(X,Y)) combines as suggested on PR41813 - accepting more post-shuffle masks even on slow-hop targets if we can fold it into another shuffle.

[RKSimon]

clang-format

[spatel]

Need to add more tests to make sure integer and 256-bit work as expected.

What do you think about consolidating the h-op creation in 1 helper as a preliminary to avoid the caller code duplication? We can also more easily assert properties of the shuffle mask (eg, only chooses from operand 0?).

I had this:

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 450927aaf5c..3ed354d483f 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -44507,21 +44507,66 @@ static bool isHorizontalBinOp(SDValue &LHS, SDValue &RHS, SelectionDAG &DAG,
   return true;
 }
 
+/// Try to synthesize horizontal add/sub from adds/subs of shuffles.
+static SDValue getHorizontalBinop(SDNode *N, SelectionDAG &DAG,
+                                  const X86Subtarget &Subtarget) {
+  unsigned Opcode = N->getOpcode();
+  unsigned HorizOpcode;
+  switch (Opcode) {
+  case ISD::ADD: HorizOpcode = X86ISD::HADD; break;
+  case ISD::SUB: HorizOpcode = X86ISD::HSUB; break;
+  case ISD::FADD: HorizOpcode = X86ISD::FHADD; break;
+  case ISD::FSUB: HorizOpcode = X86ISD::FHSUB; break;
+  default:
+    llvm_unreachable("Unexpected opcode for horizontal op");
+  }
+
+  EVT VT = N->getValueType(0);
+  if (!VT.isSimple())
+    return SDValue();
+  switch (VT.getSimpleVT().SimpleTy) {
+  case MVT::v8i16:
+  case MVT::v4i32:
+  case MVT::v16i16:
+  case MVT::v8i32:
+    // 256-bit vectors without AVX2 are handled by splitting below.
+    if (!Subtarget.hasSSSE3())
+      return SDValue();
+    break;
+  case MVT::v4f32:
+  case MVT::v2f64:
+    if (!Subtarget.hasSSE3())
+      return SDValue();
+    break;
+  case MVT::v8f32:
+  case MVT::v4f64:
+    if (!Subtarget.hasAVX())
+      return SDValue();
+    break;
+  default:
+    return SDValue();
+  }
+
+  SDValue Op0 = N->getOperand(0), Op1 = N->getOperand(1);
+  bool IsCommutable = (Opcode == ISD::ADD || Opcode == ISD::FADD);
+  if (!isHorizontalBinOp(Op0, Op1, DAG, Subtarget, IsCommutable))
+    return SDValue();
+
+  if (VT.getScalarType().isFloatingPoint())
+    return DAG.getNode(HorizOpcode, SDLoc(N), VT, Op0, Op1);
+
+  auto HopBuilder = [&](SelectionDAG &DAG, const SDLoc &DL,
+                        ArrayRef<SDValue> Ops) {
+    return DAG.getNode(HorizOpcode, DL, Ops[0].getValueType(), Ops);
+  };
+  return SplitOpsAndApply(DAG, Subtarget, SDLoc(N), VT, {Op0, Op1}, HopBuilder);
+}
+
 /// Do target-specific dag combines on floating-point adds/subs.
 static SDValue combineFaddFsub(SDNode *N, SelectionDAG &DAG,
                                const X86Subtarget &Subtarget) {

[RKSimon]

rebase

[RKSimon]

rebase with new tests

[RKSimon]

Relax lane crossing limitations for AVX2+ targets

[RKSimon]

Always permit lane crossing on AVX2 targets, and on non-AVX2 targets, integer hops will always be split to 128-bits so permit lane crossing there as well.

[spatel]

llvm/lib/Target/X86/X86ISelLowering.cpp

44457

Reduce negative logic?
// Avoid 128-bit lane crossing if this is pre-AVX2 and FP (integer will be split).
if (!Subtarget.hasAVX2 && VT.isFloatingPoint() && ...)

[RKSimon]

simplify lane-crossing logic

[spatel]

LGTM

llvm/lib/Target/X86/X86ISelLowering.cpp

 /// and
 ///   B = < float b0, float b1, float b2, float b3 >
 /// then the result of doing a horizontal operation on A and B is
 ///   A horizontal-op B = < a0 op a1, a2 op a3, b0 op b1, b2 op b3 >.
 /// In short, LHS and RHS are inspected to see if LHS op RHS is of the form
 /// A horizontal-op B, for some already available A and B, and if so then LHS is
 /// set to A, RHS to B, and the routine returns 'true'.
 static bool isHorizontalBinOp(SDValue &LHS, SDValue &RHS, SelectionDAG &DAG,
-                              const X86Subtarget &Subtarget,
-                              bool IsCommutative) {
+                              const X86Subtarget &Subtarget, bool IsCommutative,
+                              SmallVectorImpl<int> &PostShuffleMask) {
   // If either operand is undef, bail out. The binop should be simplified.
   if (LHS.isUndef() || RHS.isUndef())
     return false;
 
   // Look for the following pattern:
   //   A = < float a0, float a1, float a2, float a3 >
   //   B = < float b0, float b1, float b2, float b3 >
   // and
static bool isHorizontalBinOp(SDValue &LHS, SDValue &RHS, SelectionDAG &DAG,
   }
 
   if (RMask.empty()) {
     C = RHS;
     for (unsigned i = 0; i != NumElts; ++i)
       RMask.push_back(i);
   }
 
+  if (isLaneCrossingShuffleMask(128, VT.getScalarSizeInBits(), LMask) ||
+      isLaneCrossingShuffleMask(128, VT.getScalarSizeInBits(), RMask))
+    return false;
+
   // If A and B occur in reverse order in RHS, then canonicalize by commuting
   // RHS operands and shuffle mask.
   if (A != C) {
     std::swap(C, D);
     ShuffleVectorSDNode::commuteMask(RMask);
   }
   // Check that the shuffles are both shuffling the same vectors.
   if (!(A == C && B == D))
     return false;
 
+  PostShuffleMask.clear();
+  PostShuffleMask.append(NumElts, SM_SentinelUndef);
+
   // LHS and RHS are now:
   //   LHS = shuffle A, B, LMask
   //   RHS = shuffle A, B, RMask
   // Check that the masks correspond to performing a horizontal operation.
   // AVX defines horizontal add/sub to operate independently on 128-bit lanes,
   // so we just repeat the inner loop if this is a 256-bit op.
   unsigned Num128BitChunks = VT.getSizeInBits() / 128;
   unsigned NumEltsPer128BitChunk = NumElts / Num128BitChunks;
+  unsigned NumEltsPer64BitChunk = NumEltsPer128BitChunk / 2;
   assert((NumEltsPer128BitChunk % 2 == 0) &&
          "Vector type should have an even number of elements in each lane");
   for (unsigned j = 0; j != NumElts; j += NumEltsPer128BitChunk) {
     for (unsigned i = 0; i != NumEltsPer128BitChunk; ++i) {
       // Ignore undefined components.
       int LIdx = LMask[i + j], RIdx = RMask[i + j];
       if (LIdx < 0 || RIdx < 0 ||
           (!A.getNode() && (LIdx < (int)NumElts || RIdx < (int)NumElts)) ||
           (!B.getNode() && (LIdx >= (int)NumElts || RIdx >= (int)NumElts)))
         continue;
 
+      // Check that successive odd/even elements are being operated on. If not,
+      // this is not a horizontal operation.
+      if (!((RIdx & 1) == 1 && (LIdx + 1) == RIdx) &&
+          !((LIdx & 1) == 1 && (RIdx + 1) == LIdx && IsCommutative))
+        return false;
+
+      // Compute the post-shuffle mask index based on where the element
+      // is stored in the HOP result, and where it needs to be moved to.
+      int Base = LIdx & ~1u;
+      int Index = ((Base % NumEltsPer128BitChunk) / 2) +
+                  ((Base % NumElts) & ~(NumEltsPer128BitChunk - 1));
+
       // The  low half of the 128-bit result must choose from A.
       // The high half of the 128-bit result must choose from B,
       // unless B is undef. In that case, we are always choosing from A.
-      unsigned NumEltsPer64BitChunk = NumEltsPer128BitChunk / 2;
-      unsigned Src = B.getNode() ? i >= NumEltsPer64BitChunk : 0;
-
-      // Check that successive elements are being operated on. If not, this is
-      // not a horizontal operation.
-      int Index = 2 * (i % NumEltsPer64BitChunk) + NumElts * Src + j;
-      if (!(LIdx == Index && RIdx == Index + 1) &&
-          !(IsCommutative && LIdx == Index + 1 && RIdx == Index))
-        return false;
+      if ((B && Base >= (int)NumElts) || (!B && i >= NumEltsPer64BitChunk))
+        Index += NumEltsPer64BitChunk;
+      PostShuffleMask[i + j] = Index;
     }
   }
 
   LHS = A.getNode() ? A : B; // If A is 'UNDEF', use B for it.
   RHS = B.getNode() ? B : A; // If B is 'UNDEF', use A for it.
 
-  if (!shouldUseHorizontalOp(LHS == RHS && NumShuffles < 2, DAG, Subtarget))
+  bool IsIdentityPostShuffle =
+      isSequentialOrUndefInRange(PostShuffleMask, 0, NumElts, 0);
+  if (IsIdentityPostShuffle)
+    PostShuffleMask.clear();
+
+  // Assume a SingleSource HOP if we only shuffle one input and don't need to
+  // shuffle the result.
+  if (!shouldUseHorizontalOp(LHS == RHS &&
+                                 (NumShuffles < 2 || !IsIdentityPostShuffle),
+                             DAG, Subtarget))
     return false;
 
   LHS = DAG.getBitcast(VT, LHS);
   RHS = DAG.getBitcast(VT, RHS);
   return true;
 }
 
 /// Do target-specific dag combines on floating-point adds/subs.
 static SDValue combineFaddFsub(SDNode *N, SelectionDAG &DAG,
                                const X86Subtarget &Subtarget) {
   EVT VT = N->getValueType(0);
   SDValue LHS = N->getOperand(0);
   SDValue RHS = N->getOperand(1);
   bool IsFadd = N->getOpcode() == ISD::FADD;
   auto HorizOpcode = IsFadd ? X86ISD::FHADD : X86ISD::FHSUB;
   assert((IsFadd || N->getOpcode() == ISD::FSUB) && "Wrong opcode");
 
   // Try to synthesize horizontal add/sub from adds/subs of shuffles.
+  SmallVector<int, 8> PostShuffleMask;
   if (((Subtarget.hasSSE3() && (VT == MVT::v4f32 || VT == MVT::v2f64)) ||
        (Subtarget.hasAVX() && (VT == MVT::v8f32 || VT == MVT::v4f64))) &&
-      isHorizontalBinOp(LHS, RHS, DAG, Subtarget, IsFadd))
-    return DAG.getNode(HorizOpcode, SDLoc(N), VT, LHS, RHS);
+      isHorizontalBinOp(LHS, RHS, DAG, Subtarget, IsFadd, PostShuffleMask)) {
+    SDValue HorizBinOp = DAG.getNode(HorizOpcode, SDLoc(N), VT, LHS, RHS);
+    if (!PostShuffleMask.empty())
+      HorizBinOp = DAG.getVectorShuffle(VT, SDLoc(HorizBinOp), HorizBinOp,
+                                        DAG.getUNDEF(VT), PostShuffleMask);
+    return HorizBinOp;
+  }
 
   // NOTE: isHorizontalBinOp may have changed LHS/RHS variables.
 
   return SDValue();
 }
 
 /// Attempt to pre-truncate inputs to arithmetic ops if it will simplify
 /// the codegen.

 static SDValue combineAddOrSubToHADDorHSUB(SDNode *N, SelectionDAG &DAG,
                                            const X86Subtarget &Subtarget) {
   EVT VT = N->getValueType(0);
   SDValue Op0 = N->getOperand(0);
   SDValue Op1 = N->getOperand(1);
   bool IsAdd = N->getOpcode() == ISD::ADD;
   assert((IsAdd || N->getOpcode() == ISD::SUB) && "Wrong opcode");
 
+  SmallVector<int, 8> PostShuffleMask;
   if ((VT == MVT::v8i16 || VT == MVT::v4i32 || VT == MVT::v16i16 ||
        VT == MVT::v8i32) &&
       Subtarget.hasSSSE3() &&
-      isHorizontalBinOp(Op0, Op1, DAG, Subtarget, IsAdd)) {
+      isHorizontalBinOp(Op0, Op1, DAG, Subtarget, IsAdd, PostShuffleMask)) {
     auto HOpBuilder = [IsAdd](SelectionDAG &DAG, const SDLoc &DL,
                               ArrayRef<SDValue> Ops) {
-      return DAG.getNode(IsAdd ? X86ISD::HADD : X86ISD::HSUB,
-                         DL, Ops[0].getValueType(), Ops);
+      return DAG.getNode(IsAdd ? X86ISD::HADD : X86ISD::HSUB, DL,
+                         Ops[0].getValueType(), Ops);
     };
-    return SplitOpsAndApply(DAG, Subtarget, SDLoc(N), VT, {Op0, Op1},
-                            HOpBuilder);
+    SDValue HorizBinOp =
+        SplitOpsAndApply(DAG, Subtarget, SDLoc(N), VT, {Op0, Op1}, HOpBuilder);
+    if (!PostShuffleMask.empty())
+      HorizBinOp = DAG.getVectorShuffle(VT, SDLoc(HorizBinOp), HorizBinOp,
+                                        DAG.getUNDEF(VT), PostShuffleMask);
+    return HorizBinOp;
   }
 
   return SDValue();
 }
 
 static SDValue combineAdd(SDNode *N, SelectionDAG &DAG,
                           TargetLowering::DAGCombinerInfo &DCI,
                           const X86Subtarget &Subtarget) {

llvm/test/CodeGen/X86/haddsub-3.ll

 ; SSE2-NEXT:    movaps %xmm0, %xmm1
 ; SSE2-NEXT:    shufps {{.*#+}} xmm1 = xmm1[1,1],xmm0[3,3]
 ; SSE2-NEXT:    addps %xmm0, %xmm1
 ; SSE2-NEXT:    movaps %xmm1, %xmm0
 ; SSE2-NEXT:    unpckhpd {{.*#+}} xmm0 = xmm0[1],xmm1[1]
 ; SSE2-NEXT:    addss %xmm1, %xmm0
 ; SSE2-NEXT:    retq
 ;
-; SSSE3-LABEL: pr26491:
-; SSSE3:       # %bb.0:
-; SSSE3-NEXT:    movshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
-; SSSE3-NEXT:    addps %xmm0, %xmm1
-; SSSE3-NEXT:    movaps %xmm1, %xmm0
-; SSSE3-NEXT:    unpckhpd {{.*#+}} xmm0 = xmm0[1],xmm1[1]
-; SSSE3-NEXT:    addss %xmm1, %xmm0
-; SSSE3-NEXT:    retq
-;
-; AVX-LABEL: pr26491:
-; AVX:       # %bb.0:
-; AVX-NEXT:    vmovshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
-; AVX-NEXT:    vaddps %xmm0, %xmm1, %xmm0
-; AVX-NEXT:    vpermilpd {{.*#+}} xmm1 = xmm0[1,0]
-; AVX-NEXT:    vaddss %xmm0, %xmm1, %xmm0
-; AVX-NEXT:    retq
+; SSSE3-SLOW-LABEL: pr26491:
+; SSSE3-SLOW:       # %bb.0:
+; SSSE3-SLOW-NEXT:    movshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
+; SSSE3-SLOW-NEXT:    addps %xmm0, %xmm1
+; SSSE3-SLOW-NEXT:    movaps %xmm1, %xmm0
+; SSSE3-SLOW-NEXT:    unpckhpd {{.*#+}} xmm0 = xmm0[1],xmm1[1]
+; SSSE3-SLOW-NEXT:    addss %xmm1, %xmm0
+; SSSE3-SLOW-NEXT:    retq
+;
+; SSSE3-FAST-LABEL: pr26491:
+; SSSE3-FAST:       # %bb.0:
+; SSSE3-FAST-NEXT:    haddps %xmm0, %xmm0
+; SSSE3-FAST-NEXT:    movaps %xmm0, %xmm1
+; SSSE3-FAST-NEXT:    shufps {{.*#+}} xmm1 = xmm1[3,1],xmm0[2,3]
+; SSSE3-FAST-NEXT:    addss %xmm0, %xmm1
+; SSSE3-FAST-NEXT:    movaps %xmm1, %xmm0
+; SSSE3-FAST-NEXT:    retq
+;
+; AVX1-SLOW-LABEL: pr26491:
+; AVX1-SLOW:       # %bb.0:
+; AVX1-SLOW-NEXT:    vmovshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
+; AVX1-SLOW-NEXT:    vaddps %xmm0, %xmm1, %xmm0
+; AVX1-SLOW-NEXT:    vpermilpd {{.*#+}} xmm1 = xmm0[1,0]
+; AVX1-SLOW-NEXT:    vaddss %xmm0, %xmm1, %xmm0
+; AVX1-SLOW-NEXT:    retq
+;
+; AVX1-FAST-LABEL: pr26491:
+; AVX1-FAST:       # %bb.0:
+; AVX1-FAST-NEXT:    vhaddps %xmm0, %xmm0, %xmm0
+; AVX1-FAST-NEXT:    vpermilps {{.*#+}} xmm1 = xmm0[3,1,2,3]
+; AVX1-FAST-NEXT:    vaddss %xmm0, %xmm1, %xmm0
+; AVX1-FAST-NEXT:    retq
+;
+; AVX2-LABEL: pr26491:
+; AVX2:       # %bb.0:
+; AVX2-NEXT:    vmovshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
+; AVX2-NEXT:    vaddps %xmm0, %xmm1, %xmm0
+; AVX2-NEXT:    vpermilpd {{.*#+}} xmm1 = xmm0[1,0]
+; AVX2-NEXT:    vaddss %xmm0, %xmm1, %xmm0
+; AVX2-NEXT:    retq
   %1 = shufflevector <4 x float> %a0, <4 x float> undef, <4 x i32> <i32 1, i32 1, i32 3, i32 3>
   %2 = fadd <4 x float> %1, %a0
   %3 = extractelement <4 x float> %2, i32 2
   %4 = extractelement <4 x float> %2, i32 0
   %5 = fadd float %3, %4
   ret float %5
 }
 

llvm/test/CodeGen/X86/haddsub-shuf.ll

; AVX2-NEXT:    retq
   ret <4 x float> %2
 }
 
 declare <4 x float> @llvm.x86.sse3.hadd.ps(<4 x float>, <4 x float>)
 
 define <4 x float> @PR34724_1(<4 x float> %a, <4 x float> %b) {
 ; SSSE3_SLOW-LABEL: PR34724_1:
 ; SSSE3_SLOW:       # %bb.0:
-; SSSE3_SLOW-NEXT:    movaps %xmm1, %xmm2
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[1,0],xmm0[3,2]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[2,0],xmm0[2,3]
 ; SSSE3_SLOW-NEXT:    movhlps {{.*#+}} xmm0 = xmm0[1,1]
-; SSSE3_SLOW-NEXT:    unpcklps {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
-; SSSE3_SLOW-NEXT:    addps %xmm0, %xmm2
-; SSSE3_SLOW-NEXT:    movsldup {{.*#+}} xmm0 = xmm1[0,0,2,2]
-; SSSE3_SLOW-NEXT:    addps %xmm1, %xmm0
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm0 = xmm0[3,0],xmm2[1,0]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,0],xmm0[2,0]
-; SSSE3_SLOW-NEXT:    movaps %xmm2, %xmm0
+; SSSE3_SLOW-NEXT:    haddps %xmm1, %xmm0
+; SSSE3_SLOW-NEXT:    movsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
+; SSSE3_SLOW-NEXT:    addps %xmm1, %xmm2
+; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[3,0],xmm0[2,0]
+; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,0],xmm2[2,0]
 ; SSSE3_SLOW-NEXT:    retq
 ;
 ; SSSE3_FAST-LABEL: PR34724_1:
 ; SSSE3_FAST:       # %bb.0:
-; SSSE3_FAST-NEXT:    movaps %xmm1, %xmm2
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[1,0],xmm0[3,2]
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[2,0],xmm0[2,3]
 ; SSSE3_FAST-NEXT:    movhlps {{.*#+}} xmm0 = xmm0[1,1]
-; SSSE3_FAST-NEXT:    unpcklps {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
-; SSSE3_FAST-NEXT:    addps %xmm0, %xmm2
+; SSSE3_FAST-NEXT:    haddps %xmm1, %xmm0
 ; SSSE3_FAST-NEXT:    haddps %xmm1, %xmm1
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm1 = xmm1[3,0],xmm2[1,0]
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,0],xmm1[2,0]
-; SSSE3_FAST-NEXT:    movaps %xmm2, %xmm0
+; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm1 = xmm1[3,0],xmm0[2,0]
+; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,0],xmm1[2,0]
 ; SSSE3_FAST-NEXT:    retq
 ;
 ; AVX1_SLOW-LABEL: PR34724_1:
 ; AVX1_SLOW:       # %bb.0:
-; AVX1_SLOW-NEXT:    vpermilpd {{.*#+}} xmm2 = xmm0[1,0]
-; AVX1_SLOW-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0],xmm1[0],zero,zero
-; AVX1_SLOW-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX1_SLOW-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX1_SLOW-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
+; AVX1_SLOW-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX1_SLOW-NEXT:    vmovsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
 ; AVX1_SLOW-NEXT:    vaddps %xmm1, %xmm2, %xmm1
-; AVX1_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX1_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX1_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
+; AVX1_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,2,3]
 ; AVX1_SLOW-NEXT:    retq
 ;
 ; AVX1_FAST-LABEL: PR34724_1:
 ; AVX1_FAST:       # %bb.0:
-; AVX1_FAST-NEXT:    vpermilpd {{.*#+}} xmm2 = xmm0[1,0]
-; AVX1_FAST-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0],xmm1[0],zero,zero
-; AVX1_FAST-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX1_FAST-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX1_FAST-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
+; AVX1_FAST-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX1_FAST-NEXT:    vhaddps %xmm1, %xmm1, %xmm1
-; AVX1_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX1_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX1_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
+; AVX1_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,2,3]
 ; AVX1_FAST-NEXT:    retq
 ;
 ; AVX2_SLOW-LABEL: PR34724_1:
 ; AVX2_SLOW:       # %bb.0:
-; AVX2_SLOW-NEXT:    vpermilpd {{.*#+}} xmm2 = xmm0[1,0]
-; AVX2_SLOW-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0],xmm1[0],zero,zero
-; AVX2_SLOW-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX2_SLOW-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX2_SLOW-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
+; AVX2_SLOW-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX2_SLOW-NEXT:    vmovsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
 ; AVX2_SLOW-NEXT:    vaddps %xmm1, %xmm2, %xmm1
-; AVX2_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX2_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX2_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
+; AVX2_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,2,3]
 ; AVX2_SLOW-NEXT:    retq
 ;
 ; AVX2_FAST-LABEL: PR34724_1:
 ; AVX2_FAST:       # %bb.0:
-; AVX2_FAST-NEXT:    vpermilpd {{.*#+}} xmm2 = xmm0[1,0]
-; AVX2_FAST-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0],xmm1[0],zero,zero
-; AVX2_FAST-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX2_FAST-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX2_FAST-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
+; AVX2_FAST-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX2_FAST-NEXT:    vhaddps %xmm1, %xmm1, %xmm1
-; AVX2_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX2_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX2_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
+; AVX2_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,2,3]
 ; AVX2_FAST-NEXT:    retq
   %t0 = shufflevector <4 x float> %a, <4 x float> %b, <2 x i32> <i32 2, i32 4>
   %t1 = shufflevector <4 x float> %a, <4 x float> %b, <2 x i32> <i32 3, i32 5>
   %t2 = fadd <2 x float> %t0, %t1
   %vecinit9 = shufflevector <2 x float> %t2, <2 x float> undef, <4 x i32> <i32 undef, i32 0, i32 1, i32 undef>
   %t3 = shufflevector <4 x float> %b, <4 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 undef, i32 2>
   %t4 = fadd <4 x float> %t3, %b
   %vecinit13 = shufflevector <4 x float> %vecinit9, <4 x float> %t4, <4 x i32> <i32 undef, i32 1, i32 2, i32 7>
   ret <4 x float> %vecinit13
 }
 
 define <4 x float> @PR34724_2(<4 x float> %a, <4 x float> %b) {
 ; SSSE3_SLOW-LABEL: PR34724_2:
 ; SSSE3_SLOW:       # %bb.0:
-; SSSE3_SLOW-NEXT:    movaps %xmm1, %xmm2
-; SSSE3_SLOW-NEXT:    movsldup {{.*#+}} xmm3 = xmm1[0,0,2,2]
-; SSSE3_SLOW-NEXT:    addps %xmm1, %xmm3
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0],xmm0[2,0]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm1 = xmm1[2,0],xmm0[2,3]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[1,0],xmm0[3,0]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[2,0],xmm0[2,3]
+; SSSE3_SLOW-NEXT:    haddps %xmm1, %xmm0
+; SSSE3_SLOW-NEXT:    movsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
 ; SSSE3_SLOW-NEXT:    addps %xmm1, %xmm2
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm3 = xmm3[3,0],xmm2[1,0]
-; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,0],xmm3[2,0]
-; SSSE3_SLOW-NEXT:    movaps %xmm2, %xmm0
+; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm2 = xmm2[3,0],xmm0[2,0]
+; SSSE3_SLOW-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,1],xmm2[2,0]
 ; SSSE3_SLOW-NEXT:    retq
 ;
 ; SSSE3_FAST-LABEL: PR34724_2:
 ; SSSE3_FAST:       # %bb.0:
-; SSSE3_FAST-NEXT:    movaps %xmm1, %xmm3
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm3 = xmm3[0,0],xmm0[2,0]
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm3 = xmm3[2,0],xmm0[2,3]
-; SSSE3_FAST-NEXT:    movaps %xmm1, %xmm2
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[1,0],xmm0[3,0]
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[2,0],xmm0[2,3]
-; SSSE3_FAST-NEXT:    addps %xmm3, %xmm2
+; SSSE3_FAST-NEXT:    haddps %xmm1, %xmm0
 ; SSSE3_FAST-NEXT:    haddps %xmm1, %xmm1
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm1 = xmm1[3,0],xmm2[1,0]
-; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,0],xmm1[2,0]
-; SSSE3_FAST-NEXT:    movaps %xmm2, %xmm0
+; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm1 = xmm1[3,0],xmm0[2,0]
+; SSSE3_FAST-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,0]
 ; SSSE3_FAST-NEXT:    retq
 ;
 ; AVX1_SLOW-LABEL: PR34724_2:
 ; AVX1_SLOW:       # %bb.0:
-; AVX1_SLOW-NEXT:    vblendps {{.*#+}} xmm2 = xmm1[0,1],xmm0[2,3]
-; AVX1_SLOW-NEXT:    vpermilps {{.*#+}} xmm2 = xmm2[2,0,2,3]
-; AVX1_SLOW-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX1_SLOW-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX1_SLOW-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX1_SLOW-NEXT:    vmovsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
 ; AVX1_SLOW-NEXT:    vaddps %xmm1, %xmm2, %xmm1
-; AVX1_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX1_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX1_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
 ; AVX1_SLOW-NEXT:    retq
 ;
 ; AVX1_FAST-LABEL: PR34724_2:
 ; AVX1_FAST:       # %bb.0:
-; AVX1_FAST-NEXT:    vblendps {{.*#+}} xmm2 = xmm1[0,1],xmm0[2,3]
-; AVX1_FAST-NEXT:    vpermilps {{.*#+}} xmm2 = xmm2[2,0,2,3]
-; AVX1_FAST-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX1_FAST-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX1_FAST-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX1_FAST-NEXT:    vhaddps %xmm1, %xmm1, %xmm1
-; AVX1_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX1_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX1_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
 ; AVX1_FAST-NEXT:    retq
 ;
 ; AVX2_SLOW-LABEL: PR34724_2:
 ; AVX2_SLOW:       # %bb.0:
-; AVX2_SLOW-NEXT:    vblendps {{.*#+}} xmm2 = xmm1[0,1],xmm0[2,3]
-; AVX2_SLOW-NEXT:    vpermilps {{.*#+}} xmm2 = xmm2[2,0,2,3]
-; AVX2_SLOW-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX2_SLOW-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX2_SLOW-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX2_SLOW-NEXT:    vmovsldup {{.*#+}} xmm2 = xmm1[0,0,2,2]
 ; AVX2_SLOW-NEXT:    vaddps %xmm1, %xmm2, %xmm1
-; AVX2_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX2_SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX2_SLOW-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
 ; AVX2_SLOW-NEXT:    retq
 ;
 ; AVX2_FAST-LABEL: PR34724_2:
 ; AVX2_FAST:       # %bb.0:
-; AVX2_FAST-NEXT:    vblendps {{.*#+}} xmm2 = xmm1[0,1],xmm0[2,3]
-; AVX2_FAST-NEXT:    vpermilps {{.*#+}} xmm2 = xmm2[2,0,2,3]
-; AVX2_FAST-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[3],xmm1[1],zero,zero
-; AVX2_FAST-NEXT:    vaddps %xmm0, %xmm2, %xmm0
+; AVX2_FAST-NEXT:    vhaddps %xmm1, %xmm0, %xmm0
 ; AVX2_FAST-NEXT:    vhaddps %xmm1, %xmm1, %xmm1
-; AVX2_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3]
-; AVX2_FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,0,1,3]
+; AVX2_FAST-NEXT:    vblendps {{.*#+}} xmm0 = xmm0[0,1,2],xmm1[3]
 ; AVX2_FAST-NEXT:    retq
   %t0 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 2, i32 4, i32 undef, i32 undef>
   %t1 = shufflevector <4 x float> %a, <4 x float> %b, <4 x i32> <i32 3, i32 5, i32 undef, i32 undef>
   %t2 = fadd <4 x float> %t0, %t1
   %vecinit9 = shufflevector <4 x float> %t2, <4 x float> undef, <4 x i32> <i32 undef, i32 0, i32 1, i32 undef>
   %t3 = shufflevector <4 x float> %b, <4 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 undef, i32 2>
   %t4 = fadd <4 x float> %t3, %b
   %vecinit13 = shufflevector <4 x float> %vecinit9, <4 x float> %t4, <4 x i32> <i32 undef, i32 1, i32 2, i32 7>
   ret <4 x float> %vecinit13
 }

llvm/test/CodeGen/X86/haddsub-undef.ll

 ; AVX-NEXT:    retq
   %3 = shufflevector <4 x double> %0, <4 x double> %1, <4 x i32> <i32 undef, i32 2, i32 4, i32 6>
   %4 = shufflevector <4 x double> %0, <4 x double> %1, <4 x i32> <i32 undef, i32 3, i32 5, i32 7>
   %5 = fadd <4 x double> %3, %4
   ret <4 x double> %5
 }
 
 define <4 x float> @PR45747_1(<4 x float> %a, <4 x float> %b) nounwind {
-; SSE-LABEL: PR45747_1:
-; SSE:       # %bb.0:
-; SSE-NEXT:    movshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
-; SSE-NEXT:    addps %xmm0, %xmm1
-; SSE-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,2,2,3]
-; SSE-NEXT:    movaps %xmm1, %xmm0
-; SSE-NEXT:    retq
+; SSE-SLOW-LABEL: PR45747_1:
+; SSE-SLOW:       # %bb.0:
+; SSE-SLOW-NEXT:    movshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
+; SSE-SLOW-NEXT:    addps %xmm0, %xmm1
+; SSE-SLOW-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,2,2,3]
+; SSE-SLOW-NEXT:    movaps %xmm1, %xmm0
+; SSE-SLOW-NEXT:    retq
 ;
-; AVX-LABEL: PR45747_1:
-; AVX:       # %bb.0:
-; AVX-NEXT:    vmovshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
-; AVX-NEXT:    vaddps %xmm0, %xmm1, %xmm0
-; AVX-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,2,2,3]
-; AVX-NEXT:    retq
+; SSE-FAST-LABEL: PR45747_1:
+; SSE-FAST:       # %bb.0:
+; SSE-FAST-NEXT:    haddps %xmm0, %xmm0
+; SSE-FAST-NEXT:    retq
+;
+; AVX-SLOW-LABEL: PR45747_1:
+; AVX-SLOW:       # %bb.0:
+; AVX-SLOW-NEXT:    vmovshdup {{.*#+}} xmm1 = xmm0[1,1,3,3]
+; AVX-SLOW-NEXT:    vaddps %xmm0, %xmm1, %xmm0
+; AVX-SLOW-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,2,2,3]
+; AVX-SLOW-NEXT:    retq
+;
+; AVX-FAST-LABEL: PR45747_1:
+; AVX-FAST:       # %bb.0:
+; AVX-FAST-NEXT:    vhaddps %xmm0, %xmm0, %xmm0
+; AVX-FAST-NEXT:    retq
   %t0 = shufflevector <4 x float> %a, <4 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 3, i32 undef>
   %t1 = fadd <4 x float> %t0, %a
   %shuffle = shufflevector <4 x float> %t1, <4 x float> undef, <4 x i32> <i32 undef, i32 2, i32 undef, i32 undef>
   ret <4 x float> %shuffle
 }
 
 define <4 x float> @PR45747_2(<4 x float> %a, <4 x float> %b) nounwind {
-; SSE-LABEL: PR45747_2:
-; SSE:       # %bb.0:
-; SSE-NEXT:    movshdup {{.*#+}} xmm0 = xmm1[1,1,3,3]
-; SSE-NEXT:    addps %xmm1, %xmm0
-; SSE-NEXT:    movhlps {{.*#+}} xmm0 = xmm0[1,1]
-; SSE-NEXT:    retq
+; SSE-SLOW-LABEL: PR45747_2:
+; SSE-SLOW:       # %bb.0:
+; SSE-SLOW-NEXT:    movshdup {{.*#+}} xmm0 = xmm1[1,1,3,3]
+; SSE-SLOW-NEXT:    addps %xmm1, %xmm0
+; SSE-SLOW-NEXT:    movhlps {{.*#+}} xmm0 = xmm0[1,1]
+; SSE-SLOW-NEXT:    retq
 ;
-; AVX-LABEL: PR45747_2:
-; AVX:       # %bb.0:
-; AVX-NEXT:    vmovshdup {{.*#+}} xmm0 = xmm1[1,1,3,3]
-; AVX-NEXT:    vaddps %xmm1, %xmm0, %xmm0
-; AVX-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
-; AVX-NEXT:    retq
+; SSE-FAST-LABEL: PR45747_2:
+; SSE-FAST:       # %bb.0:
+; SSE-FAST-NEXT:    movaps %xmm1, %xmm0
+; SSE-FAST-NEXT:    haddps %xmm1, %xmm0
+; SSE-FAST-NEXT:    shufps {{.*#+}} xmm0 = xmm0[3,1,2,3]
+; SSE-FAST-NEXT:    retq
+;
+; AVX-SLOW-LABEL: PR45747_2:
+; AVX-SLOW:       # %bb.0:
+; AVX-SLOW-NEXT:    vmovshdup {{.*#+}} xmm0 = xmm1[1,1,3,3]
+; AVX-SLOW-NEXT:    vaddps %xmm1, %xmm0, %xmm0
+; AVX-SLOW-NEXT:    vpermilpd {{.*#+}} xmm0 = xmm0[1,0]
+; AVX-SLOW-NEXT:    retq
+;
+; AVX-FAST-LABEL: PR45747_2:
+; AVX-FAST:       # %bb.0:
+; AVX-FAST-NEXT:    vhaddps %xmm1, %xmm1, %xmm0
+; AVX-FAST-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[3,1,2,3]
+; AVX-FAST-NEXT:    retq
   %t0 = shufflevector <4 x float> %b, <4 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 3, i32 undef>
   %t1 = fadd <4 x float> %t0, %b
   %shuffle = shufflevector <4 x float> %t1, <4 x float> undef, <4 x i32> <i32 2, i32 undef, i32 undef, i32 undef>
   ret <4 x float> %shuffle
 }