Index: llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2215,6 +2215,15 @@
       return true;
     APInt BaseElts = DemandedElts;
     BaseElts.insertBits(APInt::getNullValue(NumSubElts), SubIdx);
+
+    // If none of the base operand elements are demanded, replace it with undef.
+    if (!BaseElts && !Base.isUndef())
+      return TLO.CombineTo(Op,
+                           TLO.DAG.getNode(ISD::INSERT_SUBVECTOR, DL, VT,
+                                           TLO.DAG.getUNDEF(VT),
+                                           Op.getOperand(1),
+                                           Op.getOperand(2)));
+
     if (SimplifyDemandedVectorElts(Base, BaseElts, KnownUndef, KnownZero, TLO,
                                    Depth + 1))
       return true;
Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -44105,23 +44105,6 @@
             combineConcatVectorOps(dl, OpVT, SubVectorOps, DAG, DCI, Subtarget))
       return Fold;
 
-  // If we are inserting into both halves of the vector, the starting vector
-  // should be undef. If it isn't, make it so. Only do this if the early insert
-  // has no other uses.
-  // TODO: Should this be a generic DAG combine?
-  // TODO: Why doesn't SimplifyDemandedVectorElts catch this?
-  if ((IdxVal == OpVT.getVectorNumElements() / 2) &&
-      Vec.getOpcode() == ISD::INSERT_SUBVECTOR &&
-      OpVT.getSizeInBits() == SubVecVT.getSizeInBits() * 2 &&
-      isNullConstant(Vec.getOperand(2)) && !Vec.getOperand(0).isUndef() &&
-      Vec.getOperand(1).getValueSizeInBits() == SubVecVT.getSizeInBits() &&
-      Vec.hasOneUse()) {
-    Vec = DAG.getNode(ISD::INSERT_SUBVECTOR, dl, OpVT, DAG.getUNDEF(OpVT),
-                      Vec.getOperand(1), Vec.getOperand(2));
-    return DAG.getNode(ISD::INSERT_SUBVECTOR, dl, OpVT, Vec, SubVec,
-                       N->getOperand(2));
-  }
-
   // If this is a broadcast insert into an upper undef, use a larger broadcast.
   if (Vec.isUndef() && IdxVal != 0 && SubVec.getOpcode() == X86ISD::VBROADCAST)
     return DAG.getNode(X86ISD::VBROADCAST, dl, OpVT, SubVec.getOperand(0));
Index: llvm/trunk/test/CodeGen/X86/masked_expandload.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/masked_expandload.ll
+++ llvm/trunk/test/CodeGen/X86/masked_expandload.ll
@@ -1331,10 +1331,9 @@
 ; AVX1OR2:       ## %bb.0:
 ; AVX1OR2-NEXT:    vmovss {{.*#+}} xmm2 = mem[0],zero,zero,zero
 ; AVX1OR2-NEXT:    vblendps {{.*#+}} ymm0 = ymm2[0],ymm0[1,2,3,4,5,6,7]
-; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm0[0],mem[0],xmm0[2,3]
-; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0,1],mem[0],xmm2[3]
-; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0,1,2],mem[0]
-; AVX1OR2-NEXT:    vblendps {{.*#+}} ymm0 = ymm2[0,1,2,3],ymm0[4,5,6,7]
+; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[0],mem[0],xmm0[2,3]
+; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[0,1],mem[0],xmm0[3]
+; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm0 = xmm0[0,1,2],mem[0]
 ; AVX1OR2-NEXT:    vmovsd {{.*#+}} xmm2 = mem[0],zero
 ; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0,1],mem[0],xmm2[3]
 ; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0,1,2],mem[0]
@@ -1343,7 +1342,6 @@
 ; AVX1OR2-NEXT:    vblendps {{.*#+}} ymm1 = ymm2[0],ymm1[1,2,3,4,5,6,7]
 ; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm1[0],mem[0],xmm1[2,3]
 ; AVX1OR2-NEXT:    vinsertps {{.*#+}} xmm2 = xmm2[0,1],mem[0],xmm2[3]
-; AVX1OR2-NEXT:    vblendps {{.*#+}} ymm2 = ymm2[0,1,2,3],ymm1[4,5,6,7]
 ; AVX1OR2-NEXT:    vextractf128 $1, %ymm1, %xmm1
 ; AVX1OR2-NEXT:    vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero
 ; AVX1OR2-NEXT:    vblendps {{.*#+}} xmm1 = xmm3[0],xmm1[1,2,3]
Index: llvm/trunk/test/CodeGen/X86/x86-interleaved-access.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/x86-interleaved-access.ll
+++ llvm/trunk/test/CodeGen/X86/x86-interleaved-access.ll
@@ -260,25 +260,25 @@
 ; AVX1-NEXT:    vpunpckhbw {{.*#+}} xmm2 = xmm2[8],xmm3[8],xmm2[9],xmm3[9],xmm2[10],xmm3[10],xmm2[11],xmm3[11],xmm2[12],xmm3[12],xmm2[13],xmm3[13],xmm2[14],xmm3[14],xmm2[15],xmm3[15]
 ; AVX1-NEXT:    vpunpckhbw {{.*#+}} xmm0 = xmm0[8],xmm6[8],xmm0[9],xmm6[9],xmm0[10],xmm6[10],xmm0[11],xmm6[11],xmm0[12],xmm6[12],xmm0[13],xmm6[13],xmm0[14],xmm6[14],xmm0[15],xmm6[15]
 ; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm3 = xmm7[0],xmm1[0],xmm7[1],xmm1[1],xmm7[2],xmm1[2],xmm7[3],xmm1[3]
+; AVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm0, %ymm3
 ; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm6 = xmm4[0],xmm5[0],xmm4[1],xmm5[1],xmm4[2],xmm5[2],xmm4[3],xmm5[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm6, %ymm3
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm7[4],xmm1[4],xmm7[5],xmm1[5],xmm7[6],xmm1[6],xmm7[7],xmm1[7]
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm1
 ; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm1 = ymm3[2,3],ymm1[2,3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm3 = xmm4[4],xmm5[4],xmm4[5],xmm5[5],xmm4[6],xmm5[6],xmm4[7],xmm5[7]
 ; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm4 = xmm9[0],xmm0[0],xmm9[1],xmm0[1],xmm9[2],xmm0[2],xmm9[3],xmm0[3]
+; AVX1-NEXT:    vinsertf128 $1, %xmm4, %ymm0, %ymm4
 ; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm5 = xmm8[0],xmm2[0],xmm8[1],xmm2[1],xmm8[2],xmm2[2],xmm8[3],xmm2[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm4, %ymm5, %ymm4
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm0 = xmm9[4],xmm0[4],xmm9[5],xmm0[5],xmm9[6],xmm0[6],xmm9[7],xmm0[7]
 ; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm0, %ymm0
 ; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm0 = ymm4[2,3],ymm0[2,3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm2 = xmm8[4],xmm2[4],xmm8[5],xmm2[5],xmm8[6],xmm2[6],xmm8[7],xmm2[7]
 ; AVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm6, %ymm3
 ; AVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm5, %ymm2
-; AVX1-NEXT:    vmovaps %ymm2, 32(%rdi)
-; AVX1-NEXT:    vmovaps %ymm3, (%rdi)
 ; AVX1-NEXT:    vmovaps %ymm0, 96(%rdi)
 ; AVX1-NEXT:    vmovaps %ymm1, 64(%rdi)
+; AVX1-NEXT:    vmovaps %ymm2, 32(%rdi)
+; AVX1-NEXT:    vmovaps %ymm3, (%rdi)
 ; AVX1-NEXT:    vzeroupper
 ; AVX1-NEXT:    retq
 ;
@@ -1568,45 +1568,45 @@
 ; AVX1-NEXT:    vpunpckhbw {{.*#+}} xmm3 = xmm5[8],xmm3[8],xmm5[9],xmm3[9],xmm5[10],xmm3[10],xmm5[11],xmm3[11],xmm5[12],xmm3[12],xmm5[13],xmm3[13],xmm5[14],xmm3[14],xmm5[15],xmm3[15]
 ; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm5 = xmm15[0],xmm0[0],xmm15[1],xmm0[1],xmm15[2],xmm0[2],xmm15[3],xmm0[3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm0 = xmm15[4],xmm0[4],xmm15[5],xmm0[5],xmm15[6],xmm0[6],xmm15[7],xmm0[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm15 = xmm10[0],xmm6[0],xmm10[1],xmm6[1],xmm10[2],xmm6[2],xmm10[3],xmm6[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm5, %ymm15, %ymm5
+; AVX1-NEXT:    vinsertf128 $1, %xmm5, %ymm0, %ymm5
 ; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm0, %ymm0
-; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm0 = ymm5[2,3],ymm0[2,3]
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm5 = xmm10[4],xmm6[4],xmm10[5],xmm6[5],xmm10[6],xmm6[6],xmm10[7],xmm6[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm6 = xmm9[0],xmm2[0],xmm9[1],xmm2[1],xmm9[2],xmm2[2],xmm9[3],xmm2[3]
+; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm15 = ymm5[2,3],ymm0[2,3]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm5 = xmm10[0],xmm6[0],xmm10[1],xmm6[1],xmm10[2],xmm6[2],xmm10[3],xmm6[3]
+; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm10 = xmm10[4],xmm6[4],xmm10[5],xmm6[5],xmm10[6],xmm6[6],xmm10[7],xmm6[7]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm0 = xmm9[0],xmm2[0],xmm9[1],xmm2[1],xmm9[2],xmm2[2],xmm9[3],xmm2[3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm2 = xmm9[4],xmm2[4],xmm9[5],xmm2[5],xmm9[6],xmm2[6],xmm9[7],xmm2[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm9 = xmm8[0],xmm14[0],xmm8[1],xmm14[1],xmm8[2],xmm14[2],xmm8[3],xmm14[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm6, %ymm9, %ymm6
+; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm0, %ymm0
 ; AVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm2
-; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm10 = ymm6[2,3],ymm2[2,3]
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm14 = xmm8[4],xmm14[4],xmm8[5],xmm14[5],xmm8[6],xmm14[6],xmm8[7],xmm14[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm2 = xmm13[0],xmm3[0],xmm13[1],xmm3[1],xmm13[2],xmm3[2],xmm13[3],xmm3[3]
+; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm9 = ymm0[2,3],ymm2[2,3]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm2 = xmm8[0],xmm14[0],xmm8[1],xmm14[1],xmm8[2],xmm14[2],xmm8[3],xmm14[3]
+; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm8 = xmm8[4],xmm14[4],xmm8[5],xmm14[5],xmm8[6],xmm14[6],xmm8[7],xmm14[7]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm6 = xmm13[0],xmm3[0],xmm13[1],xmm3[1],xmm13[2],xmm3[2],xmm13[3],xmm3[3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm3 = xmm13[4],xmm3[4],xmm13[5],xmm3[5],xmm13[6],xmm3[6],xmm13[7],xmm3[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm8 = xmm12[0],xmm7[0],xmm12[1],xmm7[1],xmm12[2],xmm7[2],xmm12[3],xmm7[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm8, %ymm2
+; AVX1-NEXT:    vinsertf128 $1, %xmm6, %ymm0, %ymm6
 ; AVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm0, %ymm3
-; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm2 = ymm2[2,3],ymm3[2,3]
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm3 = xmm12[4],xmm7[4],xmm12[5],xmm7[5],xmm12[6],xmm7[6],xmm12[7],xmm7[7]
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm7 = xmm11[0],xmm1[0],xmm11[1],xmm1[1],xmm11[2],xmm1[2],xmm11[3],xmm1[3]
+; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm3 = ymm6[2,3],ymm3[2,3]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm6 = xmm12[0],xmm7[0],xmm12[1],xmm7[1],xmm12[2],xmm7[2],xmm12[3],xmm7[3]
+; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm7 = xmm12[4],xmm7[4],xmm12[5],xmm7[5],xmm12[6],xmm7[6],xmm12[7],xmm7[7]
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm0 = xmm11[0],xmm1[0],xmm11[1],xmm1[1],xmm11[2],xmm1[2],xmm11[3],xmm1[3]
 ; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm11[4],xmm1[4],xmm11[5],xmm1[5],xmm11[6],xmm1[6],xmm11[7],xmm1[7]
-; AVX1-NEXT:    vmovdqa {{[-0-9]+}}(%r{{[sb]}}p), %xmm6 # 16-byte Reload
-; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm11 = xmm6[0],xmm4[0],xmm6[1],xmm4[1],xmm6[2],xmm4[2],xmm6[3],xmm4[3]
-; AVX1-NEXT:    vinsertf128 $1, %xmm7, %ymm11, %ymm7
+; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm0, %ymm0
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm1
-; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm1 = ymm7[2,3],ymm1[2,3]
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm4 = xmm6[4],xmm4[4],xmm6[5],xmm4[5],xmm6[6],xmm4[6],xmm6[7],xmm4[7]
-; AVX1-NEXT:    vinsertf128 $1, %xmm14, %ymm9, %ymm6
-; AVX1-NEXT:    vinsertf128 $1, %xmm4, %ymm11, %ymm4
-; AVX1-NEXT:    vinsertf128 $1, %xmm5, %ymm15, %ymm5
-; AVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm8, %ymm3
-; AVX1-NEXT:    vmovaps %ymm3, 160(%rdi)
-; AVX1-NEXT:    vmovaps %ymm5, 128(%rdi)
-; AVX1-NEXT:    vmovaps %ymm4, 32(%rdi)
-; AVX1-NEXT:    vmovaps %ymm6, (%rdi)
-; AVX1-NEXT:    vmovaps %ymm2, 224(%rdi)
-; AVX1-NEXT:    vmovaps %ymm0, 192(%rdi)
-; AVX1-NEXT:    vmovaps %ymm1, 96(%rdi)
-; AVX1-NEXT:    vmovaps %ymm10, 64(%rdi)
+; AVX1-NEXT:    vperm2f128 {{.*#+}} ymm11 = ymm0[2,3],ymm1[2,3]
+; AVX1-NEXT:    vmovdqa {{[-0-9]+}}(%r{{[sb]}}p), %xmm0 # 16-byte Reload
+; AVX1-NEXT:    vpunpcklwd {{.*#+}} xmm1 = xmm0[0],xmm4[0],xmm0[1],xmm4[1],xmm0[2],xmm4[2],xmm0[3],xmm4[3]
+; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm4 = xmm0[4],xmm4[4],xmm0[5],xmm4[5],xmm0[6],xmm4[6],xmm0[7],xmm4[7]
+; AVX1-NEXT:    vinsertf128 $1, %xmm8, %ymm2, %ymm2
+; AVX1-NEXT:    vinsertf128 $1, %xmm4, %ymm1, %ymm1
+; AVX1-NEXT:    vinsertf128 $1, %xmm10, %ymm5, %ymm4
+; AVX1-NEXT:    vinsertf128 $1, %xmm7, %ymm6, %ymm5
+; AVX1-NEXT:    vmovaps %ymm3, 224(%rdi)
+; AVX1-NEXT:    vmovaps %ymm15, 192(%rdi)
+; AVX1-NEXT:    vmovaps %ymm5, 160(%rdi)
+; AVX1-NEXT:    vmovaps %ymm4, 128(%rdi)
+; AVX1-NEXT:    vmovaps %ymm11, 96(%rdi)
+; AVX1-NEXT:    vmovaps %ymm9, 64(%rdi)
+; AVX1-NEXT:    vmovaps %ymm1, 32(%rdi)
+; AVX1-NEXT:    vmovaps %ymm2, (%rdi)
 ; AVX1-NEXT:    vzeroupper
 ; AVX1-NEXT:    retq
 ;