Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
===================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -993,22 +993,23 @@
       break;
     }
 
+    // The element inserted overwrites whatever was there, so the input demanded
+    // set is simpler than the output set.
+    unsigned IdxNo = Idx->getZExtValue();
+    APInt PreInsertDemandedElts = DemandedElts;
+    if (IdxNo < VWidth)
+      PreInsertDemandedElts.clearBit(IdxNo);
+    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), PreInsertDemandedElts,
+                                      UndefElts, Depth + 1);
+    if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
+
     // If this is inserting an element that isn't demanded, remove this
     // insertelement.
-    unsigned IdxNo = Idx->getZExtValue();
     if (IdxNo >= VWidth || !DemandedElts[IdxNo]) {
       Worklist.Add(I);
       return I->getOperand(0);
     }
 
-    // Otherwise, the element inserted overwrites whatever was there, so the
-    // input demanded set is simpler than the output set.
-    APInt DemandedElts2 = DemandedElts;
-    DemandedElts2.clearBit(IdxNo);
-    TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts2,
-                                      UndefElts, Depth + 1);
-    if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
-
     // The inserted element is defined.
     UndefElts.clearBit(IdxNo);
     break;
Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
===================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -1165,9 +1165,7 @@
   if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
     if (V != &SVI)
       return replaceInstUsesWith(SVI, V);
-    LHS = SVI.getOperand(0);
-    RHS = SVI.getOperand(1);
-    MadeChange = true;
+    return &SVI;
   }
 
   unsigned LHSWidth = LHS->getType()->getVectorNumElements();
Index: llvm/trunk/test/Transforms/InstCombine/X86/x86-pshufb.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/X86/x86-pshufb.ll
+++ llvm/trunk/test/Transforms/InstCombine/X86/x86-pshufb.ll
@@ -485,9 +485,8 @@
 
 define <32 x i8> @demanded_elts_insertion_avx2(<32 x i8> %InVec, <32 x i8> %BaseMask, i8 %M0, i8 %M22) {
 ; CHECK-LABEL: @demanded_elts_insertion_avx2(
-; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <32 x i8> %BaseMask, i8 %M0, i32 0
-; CHECK-NEXT:    [[TMP2:%.*]] = tail call <32 x i8> @llvm.x86.avx2.pshuf.b(<32 x i8> %InVec, <32 x i8> [[TMP1]])
-; CHECK-NEXT:    ret <32 x i8> [[TMP2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = tail call <32 x i8> @llvm.x86.avx2.pshuf.b(<32 x i8> %InVec, <32 x i8> %BaseMask)
+; CHECK-NEXT:    ret <32 x i8> [[TMP1]]
 ;
   %1 = insertelement <32 x i8> %BaseMask, i8 %M0, i32 0
   %2 = insertelement <32 x i8> %1, i8 %M22, i32 22
Index: llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
+++ llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
@@ -142,13 +142,11 @@
   ret <2 x i64> %result
 }
 
-; FIXME: The shuffle only demands the 0th (undef) element of 'out123', so everything should fold away.
+; The shuffle only demands the 0th (undef) element of 'out123', so everything should fold away.
 
 define <4 x float> @inselt_shuf_no_demand(float %a1, float %a2, float %a3) {
 ; CHECK-LABEL: @inselt_shuf_no_demand(
-; CHECK-NEXT:    [[OUT1:%.*]] = insertelement <4 x float> undef, float %a1, i32 1
-; CHECK-NEXT:    [[OUT12:%.*]] = insertelement <4 x float> [[OUT1]], float %a2, i32 2
-; CHECK-NEXT:    ret <4 x float> [[OUT12]]
+; CHECK-NEXT:    ret <4 x float> undef
 ;
   %out1 = insertelement <4 x float> undef, float %a1, i32 1
   %out12 = insertelement <4 x float> %out1, float %a2, i32 2
@@ -157,13 +155,11 @@
   ret <4 x float> %shuffle
 }
 
-; FIXME: The shuffle only demands the 0th (undef) element of 'out123', so everything should fold away.
+; The shuffle only demands the 0th (undef) element of 'out123', so everything should fold away.
 
 define <4 x float> @inselt_shuf_no_demand_commute(float %a1, float %a2, float %a3) {
 ; CHECK-LABEL: @inselt_shuf_no_demand_commute(
-; CHECK-NEXT:    [[OUT1:%.*]] = insertelement <4 x float> undef, float %a1, i32 1
-; CHECK-NEXT:    [[OUT12:%.*]] = insertelement <4 x float> [[OUT1]], float %a2, i32 2
-; CHECK-NEXT:    ret <4 x float> [[OUT12]]
+; CHECK-NEXT:    ret <4 x float> undef
 ;
   %out1 = insertelement <4 x float> undef, float %a1, i32 1
   %out12 = insertelement <4 x float> %out1, float %a2, i32 2
@@ -172,15 +168,14 @@
   ret <4 x float> %shuffle
 }
 
-; FIXME: The add uses 'out012' giving it multiple uses after the shuffle is transformed to also
+; The add uses 'out012' giving it multiple uses after the shuffle is transformed to also
 ; use 'out012'. The analysis should be able to see past that.
 
 define <4 x i32> @inselt_shuf_no_demand_multiuse(i32 %a0, i32 %a1, <4 x i32> %b) {
 ; CHECK-LABEL: @inselt_shuf_no_demand_multiuse(
 ; CHECK-NEXT:    [[OUT0:%.*]] = insertelement <4 x i32> undef, i32 %a0, i32 0
 ; CHECK-NEXT:    [[OUT01:%.*]] = insertelement <4 x i32> [[OUT0]], i32 %a1, i32 1
-; CHECK-NEXT:    [[OUT012:%.*]] = insertelement <4 x i32> [[OUT01]], i32 %a0, i32 2
-; CHECK-NEXT:    [[FOO:%.*]] = add <4 x i32> [[OUT012]], %b
+; CHECK-NEXT:    [[FOO:%.*]] = add <4 x i32> [[OUT01]], %b
 ; CHECK-NEXT:    ret <4 x i32> [[FOO]]
 ;
   %out0 = insertelement <4 x i32> undef, i32 %a0, i32 0