diff --git a/llvm/lib/Transforms/Scalar/Scalarizer.cpp b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
--- a/llvm/lib/Transforms/Scalar/Scalarizer.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
@@ -733,7 +733,7 @@
     auto *MidTy = FixedVectorType::get(SrcVT->getElementType(), FanIn);
     unsigned Op0I = 0;
     for (unsigned ResI = 0; ResI < DstNumElems; ++ResI) {
-      Value *V = UndefValue::get(MidTy);
+      Value *V = PoisonValue::get(MidTy);
       for (unsigned MidI = 0; MidI < FanIn; ++MidI)
         V = Builder.CreateInsertElement(V, Op0[Op0I++], Builder.getInt32(MidI),
                                         BCI.getName() + ".i" + Twine(ResI)
@@ -932,7 +932,7 @@
     if (!Op->use_empty()) {
       // The value is still needed, so recreate it using a series of
       // InsertElements.
-      Value *Res = UndefValue::get(Op->getType());
+      Value *Res = PoisonValue::get(Op->getType());
       if (auto *Ty = dyn_cast<VectorType>(Op->getType())) {
         BasicBlock *BB = Op->getParent();
         unsigned Count = cast<FixedVectorType>(Ty)->getNumElements();
diff --git a/llvm/test/Transforms/Scalarizer/basic-inseltpoison.ll b/llvm/test/Transforms/Scalarizer/basic-inseltpoison.ll
--- a/llvm/test/Transforms/Scalarizer/basic-inseltpoison.ll
+++ b/llvm/test/Transforms/Scalarizer/basic-inseltpoison.ll
@@ -33,7 +33,7 @@
 ; CHECK:   %add.i1 = fadd float %val.i1, %val.i3
 ; CHECK:   %add.i2 = fadd float %acc.i0, %acc.i2
 ; CHECK:   %add.i3 = fadd float %acc.i1, %acc.i3
-; CHECK:   %add.upto0 = insertelement <4 x float> undef, float %add.i0, i32 0
+; CHECK:   %add.upto0 = insertelement <4 x float> poison, float %add.i0, i32 0
 ; CHECK:   %add.upto1 = insertelement <4 x float> %add.upto0, float %add.i1, i32 1
 ; CHECK:   %add.upto2 = insertelement <4 x float> %add.upto1, float %add.i2, i32 2
 ; CHECK:   %add = insertelement <4 x float> %add.upto2, float %add.i3, i32 3
@@ -247,7 +247,7 @@
 ; CHECK: %res.i2 = fadd float %x.i2, 3.0{{[e+0]*}}, !fpmath ![[TAG]]
 ; CHECK: %x.i3 = extractelement <4 x float> %x, i32 3
 ; CHECK: %res.i3 = fadd float %x.i3, 4.0{{[e+0]*}}, !fpmath ![[TAG]]
-; CHECK: %res.upto0 = insertelement <4 x float> undef, float %res.i0, i32 0
+; CHECK: %res.upto0 = insertelement <4 x float> poison, float %res.i0, i32 0
 ; CHECK: %res.upto1 = insertelement <4 x float> %res.upto0, float %res.i1, i32 1
 ; CHECK: %res.upto2 = insertelement <4 x float> %res.upto1, float %res.i2, i32 2
 ; CHECK: %res = insertelement <4 x float> %res.upto2, float %res.i3, i32 3
@@ -403,7 +403,7 @@
 ; CHECK: %this_acc.i2 = phi float [ %acc.i2, %entry ], [ %next_acc.i2, %loop ]
 ; CHECK: %this_acc.i3 = phi float [ %acc.i3, %entry ], [ %next_acc.i3, %loop ]
 ; CHECK: %this_count = phi i32 [ %count, %entry ], [ %next_count, %loop ]
-; CHECK: %this_acc.upto0 = insertelement <4 x float> undef, float %this_acc.i0, i32 0
+; CHECK: %this_acc.upto0 = insertelement <4 x float> poison, float %this_acc.i0, i32 0
 ; CHECK: %this_acc.upto1 = insertelement <4 x float> %this_acc.upto0, float %this_acc.i1, i32 1
 ; CHECK: %this_acc.upto2 = insertelement <4 x float> %this_acc.upto1, float %this_acc.i2, i32 2
 ; CHECK: %this_acc = insertelement <4 x float> %this_acc.upto2, float %this_acc.i3, i32 3
@@ -440,7 +440,7 @@
 ; CHECK: %neg.i1 = fneg float %val.i1
 ; CHECK: %neg.i2 = fneg float %val.i2
 ; CHECK: %neg.i3 = fneg float %val.i3
-; CHECK: %neg.upto0 = insertelement <4 x float> undef, float %neg.i0, i32 0
+; CHECK: %neg.upto0 = insertelement <4 x float> poison, float %neg.i0, i32 0
 ; CHECK: %neg.upto1 = insertelement <4 x float> %neg.upto0, float %neg.i1, i32 1
 ; CHECK: %neg.upto2 = insertelement <4 x float> %neg.upto1, float %neg.i2, i32 2
 ; CHECK: %neg = insertelement <4 x float> %neg.upto2, float %neg.i3, i32 3
@@ -543,7 +543,7 @@
 define <2 x i32> @f23_crash(<2 x i32> %srcvec, i32 %v1) {
 ; CHECK-LABEL: @f23_crash(
 ; CHECK: %v0 = extractelement <2 x i32> %srcvec, i32 0
-; CHECK: %t1.upto0 = insertelement <2 x i32> undef, i32 %v0, i32 0
+; CHECK: %t1.upto0 = insertelement <2 x i32> poison, i32 %v0, i32 0
 ; CHECK: %t1 = insertelement <2 x i32> %t1.upto0, i32 %v1, i32 1
 ; CHECK: ret <2 x i32> %t1
   %v0 = extractelement <2 x i32> %srcvec, i32 0
diff --git a/llvm/test/Transforms/Scalarizer/basic.ll b/llvm/test/Transforms/Scalarizer/basic.ll
--- a/llvm/test/Transforms/Scalarizer/basic.ll
+++ b/llvm/test/Transforms/Scalarizer/basic.ll
@@ -33,7 +33,7 @@
 ; CHECK:   %add.i1 = fadd float %val.i1, %val.i3
 ; CHECK:   %add.i2 = fadd float %acc.i0, %acc.i2
 ; CHECK:   %add.i3 = fadd float %acc.i1, %acc.i3
-; CHECK:   %add.upto0 = insertelement <4 x float> undef, float %add.i0, i32 0
+; CHECK:   %add.upto0 = insertelement <4 x float> poison, float %add.i0, i32 0
 ; CHECK:   %add.upto1 = insertelement <4 x float> %add.upto0, float %add.i1, i32 1
 ; CHECK:   %add.upto2 = insertelement <4 x float> %add.upto1, float %add.i2, i32 2
 ; CHECK:   %add = insertelement <4 x float> %add.upto2, float %add.i3, i32 3
@@ -247,7 +247,7 @@
 ; CHECK: %res.i2 = fadd float %x.i2, 3.0{{[e+0]*}}, !fpmath ![[TAG]]
 ; CHECK: %x.i3 = extractelement <4 x float> %x, i32 3
 ; CHECK: %res.i3 = fadd float %x.i3, 4.0{{[e+0]*}}, !fpmath ![[TAG]]
-; CHECK: %res.upto0 = insertelement <4 x float> undef, float %res.i0, i32 0
+; CHECK: %res.upto0 = insertelement <4 x float> poison, float %res.i0, i32 0
 ; CHECK: %res.upto1 = insertelement <4 x float> %res.upto0, float %res.i1, i32 1
 ; CHECK: %res.upto2 = insertelement <4 x float> %res.upto1, float %res.i2, i32 2
 ; CHECK: %res = insertelement <4 x float> %res.upto2, float %res.i3, i32 3
@@ -403,7 +403,7 @@
 ; CHECK: %this_acc.i2 = phi float [ %acc.i2, %entry ], [ %next_acc.i2, %loop ]
 ; CHECK: %this_acc.i3 = phi float [ %acc.i3, %entry ], [ %next_acc.i3, %loop ]
 ; CHECK: %this_count = phi i32 [ %count, %entry ], [ %next_count, %loop ]
-; CHECK: %this_acc.upto0 = insertelement <4 x float> undef, float %this_acc.i0, i32 0
+; CHECK: %this_acc.upto0 = insertelement <4 x float> poison, float %this_acc.i0, i32 0
 ; CHECK: %this_acc.upto1 = insertelement <4 x float> %this_acc.upto0, float %this_acc.i1, i32 1
 ; CHECK: %this_acc.upto2 = insertelement <4 x float> %this_acc.upto1, float %this_acc.i2, i32 2
 ; CHECK: %this_acc = insertelement <4 x float> %this_acc.upto2, float %this_acc.i3, i32 3
@@ -440,7 +440,7 @@
 ; CHECK: %neg.i1 = fneg float %val.i1
 ; CHECK: %neg.i2 = fneg float %val.i2
 ; CHECK: %neg.i3 = fneg float %val.i3
-; CHECK: %neg.upto0 = insertelement <4 x float> undef, float %neg.i0, i32 0
+; CHECK: %neg.upto0 = insertelement <4 x float> poison, float %neg.i0, i32 0
 ; CHECK: %neg.upto1 = insertelement <4 x float> %neg.upto0, float %neg.i1, i32 1
 ; CHECK: %neg.upto2 = insertelement <4 x float> %neg.upto1, float %neg.i2, i32 2
 ; CHECK: %neg = insertelement <4 x float> %neg.upto2, float %neg.i3, i32 3
@@ -543,7 +543,7 @@
 define <2 x i32> @f23_crash(<2 x i32> %srcvec, i32 %v1) {
 ; CHECK-LABEL: @f23_crash(
 ; CHECK: %v0 = extractelement <2 x i32> %srcvec, i32 0
-; CHECK: %t1.upto0 = insertelement <2 x i32> undef, i32 %v0, i32 0
+; CHECK: %t1.upto0 = insertelement <2 x i32> poison, i32 %v0, i32 0
 ; CHECK: %t1 = insertelement <2 x i32> %t1.upto0, i32 %v1, i32 1
 ; CHECK: ret <2 x i32> %t1
   %v0 = extractelement <2 x i32> %srcvec, i32 0
diff --git a/llvm/test/Transforms/Scalarizer/constant-insertelement.ll b/llvm/test/Transforms/Scalarizer/constant-insertelement.ll
--- a/llvm/test/Transforms/Scalarizer/constant-insertelement.ll
+++ b/llvm/test/Transforms/Scalarizer/constant-insertelement.ll
@@ -16,7 +16,7 @@
 ; ALL-NEXT:    [[VAL2_I1:%.*]] = shl i32 2, [[VAL0_I1]]
 ; ALL-NEXT:    [[VAL2_I2:%.*]] = shl i32 3, [[VAL0_I2]]
 ; ALL-NEXT:    [[VAL2_I3:%.*]] = shl i32 4, [[REPL:%.*]]
-; ALL-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> undef, i32 [[VAL2_I0]], i32 0
+; ALL-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> poison, i32 [[VAL2_I0]], i32 0
 ; ALL-NEXT:    [[VAL2_UPTO1:%.*]] = insertelement <4 x i32> [[VAL2_UPTO0]], i32 [[VAL2_I1]], i32 1
 ; ALL-NEXT:    [[VAL2_UPTO2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO1]], i32 [[VAL2_I2]], i32 2
 ; ALL-NEXT:    [[VAL2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO2]], i32 [[VAL2_I3]], i32 3
diff --git a/llvm/test/Transforms/Scalarizer/intrinsics.ll b/llvm/test/Transforms/Scalarizer/intrinsics.ll
--- a/llvm/test/Transforms/Scalarizer/intrinsics.ll
+++ b/llvm/test/Transforms/Scalarizer/intrinsics.ll
@@ -29,7 +29,7 @@
 ; CHECK-LABEL: @scalarize_sqrt_v2f32(
 ; CHECK: %sqrt.i0 = call float @llvm.sqrt.f32(float %x.i0)
 ; CHECK: %sqrt.i1 = call float @llvm.sqrt.f32(float %x.i1)
-; CHECK: %sqrt.upto0 = insertelement <2 x float> undef, float %sqrt.i0, i32 0
+; CHECK: %sqrt.upto0 = insertelement <2 x float> poison, float %sqrt.i0, i32 0
 ; CHECK: %sqrt = insertelement <2 x float> %sqrt.upto0, float %sqrt.i1, i32 1
 ; CHECK: ret <2 x float> %sqrt
 define <2 x float> @scalarize_sqrt_v2f32(<2 x float> %x) #0 {
@@ -40,7 +40,7 @@
 ; CHECK-LABEL: @scalarize_minnum_v2f32(
 ; CHECK: %minnum.i0 = call float @llvm.minnum.f32(float %x.i0, float %y.i0)
 ; CHECK: %minnum.i1 = call float @llvm.minnum.f32(float %x.i1, float %y.i1)
-; CHECK: %minnum.upto0 = insertelement <2 x float> undef, float %minnum.i0, i32 0
+; CHECK: %minnum.upto0 = insertelement <2 x float> poison, float %minnum.i0, i32 0
 ; CHECK: %minnum = insertelement <2 x float> %minnum.upto0, float %minnum.i1, i32 1
 ; CHECK: ret <2 x float> %minnum
 define <2 x float> @scalarize_minnum_v2f32(<2 x float> %x, <2 x float> %y) #0 {
@@ -51,7 +51,7 @@
 ; CHECK-LABEL: @scalarize_minimum_v2f32(
 ; CHECK: %minimum.i0 = call float @llvm.minimum.f32(float %x.i0, float %y.i0)
 ; CHECK: %minimum.i1 = call float @llvm.minimum.f32(float %x.i1, float %y.i1)
-; CHECK: %minimum.upto0 = insertelement <2 x float> undef, float %minimum.i0, i32 0
+; CHECK: %minimum.upto0 = insertelement <2 x float> poison, float %minimum.i0, i32 0
 ; CHECK: %minimum = insertelement <2 x float> %minimum.upto0, float %minimum.i1, i32 1
 ; CHECK: ret <2 x float> %minimum
 define <2 x float> @scalarize_minimum_v2f32(<2 x float> %x, <2 x float> %y) #0 {
@@ -62,7 +62,7 @@
 ; CHECK-LABEL: @scalarize_maximum_v2f32(
 ; CHECK: %maximum.i0 = call float @llvm.maximum.f32(float %x.i0, float %y.i0)
 ; CHECK: %maximum.i1 = call float @llvm.maximum.f32(float %x.i1, float %y.i1)
-; CHECK: %maximum.upto0 = insertelement <2 x float> undef, float %maximum.i0, i32 0
+; CHECK: %maximum.upto0 = insertelement <2 x float> poison, float %maximum.i0, i32 0
 ; CHECK: %maximum = insertelement <2 x float> %maximum.upto0, float %maximum.i1, i32 1
 ; CHECK: ret <2 x float> %maximum
 define <2 x float> @scalarize_maximum_v2f32(<2 x float> %x, <2 x float> %y) #0 {
@@ -73,7 +73,7 @@
 ; CHECK-LABEL: @scalarize_fma_v2f32(
 ; CHECK: %fma.i0 = call float @llvm.fma.f32(float %x.i0, float %y.i0, float %z.i0)
 ; CHECK: %fma.i1 = call float @llvm.fma.f32(float %x.i1, float %y.i1, float %z.i1)
-; CHECK: %fma.upto0 = insertelement <2 x float> undef, float %fma.i0, i32 0
+; CHECK: %fma.upto0 = insertelement <2 x float> poison, float %fma.i0, i32 0
 ; CHECK: %fma = insertelement <2 x float> %fma.upto0, float %fma.i1, i32 1
 ; CHECK: ret <2 x float> %fma
 define <2 x float> @scalarize_fma_v2f32(<2 x float> %x, <2 x float> %y, <2 x float> %z) #0 {
@@ -84,7 +84,7 @@
 ; CHECK-LABEL: @scalarize_bswap_v2i32(
 ; CHECK: %bswap.i0 = call i32 @llvm.bswap.i32(i32 %x.i0)
 ; CHECK: %bswap.i1 = call i32 @llvm.bswap.i32(i32 %x.i1)
-; CHECK: %bswap.upto0 = insertelement <2 x i32> undef, i32 %bswap.i0, i32 0
+; CHECK: %bswap.upto0 = insertelement <2 x i32> poison, i32 %bswap.i0, i32 0
 ; CHECK: %bswap = insertelement <2 x i32> %bswap.upto0, i32 %bswap.i1, i32 1
 ; CHECK: ret <2 x i32> %bswap
 define <2 x i32> @scalarize_bswap_v2i32(<2 x i32> %x) #0 {
@@ -95,7 +95,7 @@
 ; CHECK-LABEL: @scalarize_ctlz_v2i32(
 ; CHECK: %ctlz.i0 = call i32 @llvm.ctlz.i32(i32 %x.i0, i1 true)
 ; CHECK: %ctlz.i1 = call i32 @llvm.ctlz.i32(i32 %x.i1, i1 true)
-; CHECK: %ctlz.upto0 = insertelement <2 x i32> undef, i32 %ctlz.i0, i32 0
+; CHECK: %ctlz.upto0 = insertelement <2 x i32> poison, i32 %ctlz.i0, i32 0
 ; CHECK: %ctlz = insertelement <2 x i32> %ctlz.upto0, i32 %ctlz.i1, i32 1
 ; CHECK: ret <2 x i32> %ctlz
 define <2 x i32> @scalarize_ctlz_v2i32(<2 x i32> %x) #0 {
@@ -106,7 +106,7 @@
 ; CHECK-LABEL: @scalarize_powi_v2f32(
 ; CHECK: %powi.i0 = call float @llvm.powi.f32(float %x.i0, i32 %y)
 ; CHECK: %powi.i1 = call float @llvm.powi.f32(float %x.i1, i32 %y)
-; CHECK: %powi.upto0 = insertelement <2 x float> undef, float %powi.i0, i32 0
+; CHECK: %powi.upto0 = insertelement <2 x float> poison, float %powi.i0, i32 0
 ; CHECK: %powi = insertelement <2 x float> %powi.upto0, float %powi.i1, i32 1
 ; CHECK: ret <2 x float> %powi
 define <2 x float> @scalarize_powi_v2f32(<2 x float> %x, i32 %y) #0 {
@@ -117,7 +117,7 @@
 ; CHECK-LABEL: @scalarize_smul_fix_sat_v2i32(
 ; CHECK: %smulfixsat.i0 = call i32 @llvm.smul.fix.sat.i32(i32 %x.i0, i32 5, i32 31)
 ; CHECK: %smulfixsat.i1 = call i32 @llvm.smul.fix.sat.i32(i32 %x.i1, i32 19, i32 31)
-; CHECK: %smulfixsat.upto0 = insertelement <2 x i32> undef, i32 %smulfixsat.i0, i32 0
+; CHECK: %smulfixsat.upto0 = insertelement <2 x i32> poison, i32 %smulfixsat.i0, i32 0
 ; CHECK: %smulfixsat = insertelement <2 x i32> %smulfixsat.upto0, i32 %smulfixsat.i1, i32 1
 ; CHECK: ret <2 x i32> %smulfixsat
 define <2 x i32> @scalarize_smul_fix_sat_v2i32(<2 x i32> %x) #0 {
@@ -128,7 +128,7 @@
 ; CHECK-LABEL: @scalarize_umul_fix_sat_v2i32(
 ; CHECK: %umulfixsat.i0 = call i32 @llvm.umul.fix.sat.i32(i32 %x.i0, i32 5, i32 31)
 ; CHECK: %umulfixsat.i1 = call i32 @llvm.umul.fix.sat.i32(i32 %x.i1, i32 19, i32 31)
-; CHECK: %umulfixsat.upto0 = insertelement <2 x i32> undef, i32 %umulfixsat.i0, i32 0
+; CHECK: %umulfixsat.upto0 = insertelement <2 x i32> poison, i32 %umulfixsat.i0, i32 0
 ; CHECK: %umulfixsat = insertelement <2 x i32> %umulfixsat.upto0, i32 %umulfixsat.i1, i32 1
 ; CHECK: ret <2 x i32> %umulfixsat
 define <2 x i32> @scalarize_umul_fix_sat_v2i32(<2 x i32> %x) #0 {
diff --git a/llvm/test/Transforms/Scalarizer/order-bug-inseltpoison.ll b/llvm/test/Transforms/Scalarizer/order-bug-inseltpoison.ll
--- a/llvm/test/Transforms/Scalarizer/order-bug-inseltpoison.ll
+++ b/llvm/test/Transforms/Scalarizer/order-bug-inseltpoison.ll
@@ -10,7 +10,7 @@
   br label %z
 
 y:
-; CHECK: %f.upto0 = insertelement <4 x i32> undef, i32 %b.i0, i32 0
+; CHECK: %f.upto0 = insertelement <4 x i32> poison, i32 %b.i0, i32 0
 ; CHECK: %f.upto1 = insertelement <4 x i32> %f.upto0, i32 %b.i0, i32 1
 ; CHECK: %f.upto2 = insertelement <4 x i32> %f.upto1, i32 %b.i0, i32 2
 ; CHECK: %f = insertelement <4 x i32> %f.upto2, i32 %b.i0, i32 3
diff --git a/llvm/test/Transforms/Scalarizer/order-bug.ll b/llvm/test/Transforms/Scalarizer/order-bug.ll
--- a/llvm/test/Transforms/Scalarizer/order-bug.ll
+++ b/llvm/test/Transforms/Scalarizer/order-bug.ll
@@ -10,7 +10,7 @@
   br label %z
 
 y:
-; CHECK: %f.upto0 = insertelement <4 x i32> undef, i32 %b.i0, i32 0
+; CHECK: %f.upto0 = insertelement <4 x i32> poison, i32 %b.i0, i32 0
 ; CHECK: %f.upto1 = insertelement <4 x i32> %f.upto0, i32 %b.i0, i32 1
 ; CHECK: %f.upto2 = insertelement <4 x i32> %f.upto1, i32 %b.i0, i32 2
 ; CHECK: %f = insertelement <4 x i32> %f.upto2, i32 %b.i0, i32 3
diff --git a/llvm/test/Transforms/Scalarizer/scatter-order.ll b/llvm/test/Transforms/Scalarizer/scatter-order.ll
--- a/llvm/test/Transforms/Scalarizer/scatter-order.ll
+++ b/llvm/test/Transforms/Scalarizer/scatter-order.ll
@@ -18,7 +18,7 @@
 ; CHECK-NEXT:    [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
 ; CHECK-NEXT:    [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
 ; CHECK-NEXT:    [[RES_I1:%.*]] = select i1 [[B]], i32 [[I_I1]], i32 [[J_I1]]
-; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
+; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> poison, i32 [[RES_I0]], i32 0
 ; CHECK-NEXT:    [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
 ; CHECK-NEXT:    ret <2 x i32> [[RES]]
 ;
@@ -36,7 +36,7 @@
 ; CHECK-NEXT:    [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
 ; CHECK-NEXT:    [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
 ; CHECK-NEXT:    [[RES_I1:%.*]] = select i1 [[B_I1]], i32 [[I_I1]], i32 [[J_I1]]
-; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
+; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> poison, i32 [[RES_I0]], i32 0
 ; CHECK-NEXT:    [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
 ; CHECK-NEXT:    ret <2 x i32> [[RES]]
 ;
@@ -52,7 +52,7 @@
 ; CHECK-NEXT:    [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
 ; CHECK-NEXT:    [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
 ; CHECK-NEXT:    [[RES_I1:%.*]] = add nuw nsw i32 [[I_I1]], [[J_I1]]
-; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
+; CHECK-NEXT:    [[RES_UPTO0:%.*]] = insertelement <2 x i32> poison, i32 [[RES_I0]], i32 0
 ; CHECK-NEXT:    [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
 ; CHECK-NEXT:    ret <2 x i32> [[RES]]
 ;
diff --git a/llvm/test/Transforms/Scalarizer/variable-extractelement.ll b/llvm/test/Transforms/Scalarizer/variable-extractelement.ll
--- a/llvm/test/Transforms/Scalarizer/variable-extractelement.ll
+++ b/llvm/test/Transforms/Scalarizer/variable-extractelement.ll
@@ -61,7 +61,7 @@
 ; OFF-NEXT:    [[VAL1_I2:%.*]] = shl i32 3, [[VAL0_I2]]
 ; OFF-NEXT:    [[VAL0_I3:%.*]] = extractelement <4 x i32> [[VAL0]], i32 3
 ; OFF-NEXT:    [[VAL1_I3:%.*]] = shl i32 4, [[VAL0_I3]]
-; OFF-NEXT:    [[VAL1_UPTO0:%.*]] = insertelement <4 x i32> undef, i32 [[VAL1_I0]], i32 0
+; OFF-NEXT:    [[VAL1_UPTO0:%.*]] = insertelement <4 x i32> poison, i32 [[VAL1_I0]], i32 0
 ; OFF-NEXT:    [[VAL1_UPTO1:%.*]] = insertelement <4 x i32> [[VAL1_UPTO0]], i32 [[VAL1_I1]], i32 1
 ; OFF-NEXT:    [[VAL1_UPTO2:%.*]] = insertelement <4 x i32> [[VAL1_UPTO1]], i32 [[VAL1_I2]], i32 2
 ; OFF-NEXT:    [[VAL1:%.*]] = insertelement <4 x i32> [[VAL1_UPTO2]], i32 [[VAL1_I3]], i32 3
diff --git a/llvm/test/Transforms/Scalarizer/variable-insertelement.ll b/llvm/test/Transforms/Scalarizer/variable-insertelement.ll
--- a/llvm/test/Transforms/Scalarizer/variable-insertelement.ll
+++ b/llvm/test/Transforms/Scalarizer/variable-insertelement.ll
@@ -20,7 +20,7 @@
 ; DEFAULT-NEXT:    [[INDEX_IS_3:%.*]] = icmp eq i32 [[INDEX]], 3
 ; DEFAULT-NEXT:    [[SRC_I3:%.*]] = extractelement <4 x i32> [[SRC]], i32 3
 ; DEFAULT-NEXT:    [[RES_I3:%.*]] = select i1 [[INDEX_IS_3]], i32 [[VAL]], i32 [[SRC_I3]]
-; DEFAULT-NEXT:    [[RES_UPTO0:%.*]] = insertelement <4 x i32> undef, i32 [[RES_I0]], i32 0
+; DEFAULT-NEXT:    [[RES_UPTO0:%.*]] = insertelement <4 x i32> poison, i32 [[RES_I0]], i32 0
 ; DEFAULT-NEXT:    [[RES_UPTO1:%.*]] = insertelement <4 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
 ; DEFAULT-NEXT:    [[RES_UPTO2:%.*]] = insertelement <4 x i32> [[RES_UPTO1]], i32 [[RES_I2]], i32 2
 ; DEFAULT-NEXT:    [[RES:%.*]] = insertelement <4 x i32> [[RES_UPTO2]], i32 [[RES_I3]], i32 3
@@ -53,7 +53,7 @@
 ; DEFAULT-NEXT:    [[VAL2_I1:%.*]] = shl i32 2, [[VAL1_I1]]
 ; DEFAULT-NEXT:    [[VAL2_I2:%.*]] = shl i32 3, [[VAL1_I2]]
 ; DEFAULT-NEXT:    [[VAL2_I3:%.*]] = shl i32 4, [[VAL1_I3]]
-; DEFAULT-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> undef, i32 [[VAL2_I0]], i32 0
+; DEFAULT-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> poison, i32 [[VAL2_I0]], i32 0
 ; DEFAULT-NEXT:    [[VAL2_UPTO1:%.*]] = insertelement <4 x i32> [[VAL2_UPTO0]], i32 [[VAL2_I1]], i32 1
 ; DEFAULT-NEXT:    [[VAL2_UPTO2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO1]], i32 [[VAL2_I2]], i32 2
 ; DEFAULT-NEXT:    [[VAL2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO2]], i32 [[VAL2_I3]], i32 3
@@ -71,7 +71,7 @@
 ; OFF-NEXT:    [[VAL2_I2:%.*]] = shl i32 3, [[VAL1_I2]]
 ; OFF-NEXT:    [[VAL1_I3:%.*]] = extractelement <4 x i32> [[VAL1]], i32 3
 ; OFF-NEXT:    [[VAL2_I3:%.*]] = shl i32 4, [[VAL1_I3]]
-; OFF-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> undef, i32 [[VAL2_I0]], i32 0
+; OFF-NEXT:    [[VAL2_UPTO0:%.*]] = insertelement <4 x i32> poison, i32 [[VAL2_I0]], i32 0
 ; OFF-NEXT:    [[VAL2_UPTO1:%.*]] = insertelement <4 x i32> [[VAL2_UPTO0]], i32 [[VAL2_I1]], i32 1
 ; OFF-NEXT:    [[VAL2_UPTO2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO1]], i32 [[VAL2_I2]], i32 2
 ; OFF-NEXT:    [[VAL2:%.*]] = insertelement <4 x i32> [[VAL2_UPTO2]], i32 [[VAL2_I3]], i32 3