diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4401,10 +4401,10 @@
   if (Q.isUndefValue(Idx))
     return PoisonValue::get(Vec->getType());
 
-  // If the scalar is undef, and there is no risk of propagating poison from the
-  // vector value, simplify to the vector value.
-  if (Q.isUndefValue(Val) &&
-      isGuaranteedNotToBeUndefOrPoison(Vec))
+  // If the scalar is poison, or it is undef and there is no risk of
+  // propagating poison from the vector value, simplify to the vector value.
+  if (isa<PoisonValue>(Val) ||
+      (Q.isUndefValue(Val) && isGuaranteedNotToBePoison(Vec)))
     return Vec;
 
   // If we are extracting a value from a vector, then inserting it into the same
diff --git a/llvm/test/Transforms/InstCombine/extractelement-inseltpoison.ll b/llvm/test/Transforms/InstCombine/extractelement-inseltpoison.ll
--- a/llvm/test/Transforms/InstCombine/extractelement-inseltpoison.ll
+++ b/llvm/test/Transforms/InstCombine/extractelement-inseltpoison.ll
@@ -319,8 +319,7 @@
 ; ANY-NEXT:    [[T4:%.*]] = shufflevector <4 x double> [[B:%.*]], <4 x double> [[TMP1]], <4 x i32> <i32 undef, i32 1, i32 4, i32 3>
 ; ANY-NEXT:    [[E:%.*]] = extractelement <4 x double> [[B]], i32 1
 ; ANY-NEXT:    store double [[E]], double* [[P:%.*]], align 8
-; ANY-NEXT:    [[R:%.*]] = insertelement <4 x double> [[T4]], double poison, i64 0
-; ANY-NEXT:    ret <4 x double> [[R]]
+; ANY-NEXT:    ret <4 x double> [[T4]]
 ;
   %t3 = extractelement <2 x double> %a, i32 0
   %t4 = insertelement <4 x double> %b, double %t3, i32 2
diff --git a/llvm/test/Transforms/InstCombine/extractelement.ll b/llvm/test/Transforms/InstCombine/extractelement.ll
--- a/llvm/test/Transforms/InstCombine/extractelement.ll
+++ b/llvm/test/Transforms/InstCombine/extractelement.ll
@@ -319,8 +319,7 @@
 ; ANY-NEXT:    [[T4:%.*]] = shufflevector <4 x double> [[B:%.*]], <4 x double> [[TMP1]], <4 x i32> <i32 undef, i32 1, i32 4, i32 3>
 ; ANY-NEXT:    [[E:%.*]] = extractelement <4 x double> [[B]], i32 1
 ; ANY-NEXT:    store double [[E]], double* [[P:%.*]], align 8
-; ANY-NEXT:    [[R:%.*]] = insertelement <4 x double> [[T4]], double poison, i64 0
-; ANY-NEXT:    ret <4 x double> [[R]]
+; ANY-NEXT:    ret <4 x double> [[T4]]
 ;
   %t3 = extractelement <2 x double> %a, i32 0
   %t4 = insertelement <4 x double> %b, double %t3, i32 2
diff --git a/llvm/test/Transforms/InstSimplify/insertelement.ll b/llvm/test/Transforms/InstSimplify/insertelement.ll
--- a/llvm/test/Transforms/InstSimplify/insertelement.ll
+++ b/llvm/test/Transforms/InstSimplify/insertelement.ll
@@ -52,8 +52,7 @@
 
 define <4 x i32> @elem_poison(<4 x i32> %A) {
 ; CHECK-LABEL: @elem_poison(
-; CHECK-NEXT:    [[B:%.*]] = insertelement <4 x i32> [[A:%.*]], i32 poison, i32 1
-; CHECK-NEXT:    ret <4 x i32> [[B]]
+; CHECK-NEXT:    ret <4 x i32> [[A:%.*]]
 ;
   %B = insertelement <4 x i32> %A, i32 poison, i32 1
   ret <4 x i32> %B
diff --git a/llvm/test/Transforms/SLPVectorizer/X86/alternate-int.ll b/llvm/test/Transforms/SLPVectorizer/X86/alternate-int.ll
--- a/llvm/test/Transforms/SLPVectorizer/X86/alternate-int.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/alternate-int.ll
@@ -425,10 +425,10 @@
 ; CHECK-NEXT:    [[AB5:%.*]] = sdiv i32 [[A5]], 4
 ; CHECK-NEXT:    [[AB6:%.*]] = sdiv i32 [[A6]], 8
 ; CHECK-NEXT:    [[AB7:%.*]] = sdiv i32 [[A7]], 16
-; CHECK-NEXT:    [[TMP1:%.*]] = insertelement <8 x i32> poison, i32 [[AB1]], i32 1
-; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <8 x i32> [[TMP1]], i32 [[AB2]], i32 2
-; CHECK-NEXT:    [[R4:%.*]] = insertelement <8 x i32> [[TMP2]], i32 [[AB3]], i32 3
-; CHECK-NEXT:    [[R5:%.*]] = insertelement <8 x i32> [[R4]], i32 [[AB5]], i32 5
+; CHECK-NEXT:    [[R1:%.*]] = insertelement <8 x i32> <i32 poison, i32 poison, i32 poison, i32 poison, i32 undef, i32 poison, i32 poison, i32 poison>, i32 [[AB1]], i32 1
+; CHECK-NEXT:    [[R2:%.*]] = insertelement <8 x i32> [[R1]], i32 [[AB2]], i32 2
+; CHECK-NEXT:    [[R3:%.*]] = insertelement <8 x i32> [[R2]], i32 [[AB3]], i32 3
+; CHECK-NEXT:    [[R5:%.*]] = insertelement <8 x i32> [[R3]], i32 [[AB5]], i32 5
 ; CHECK-NEXT:    [[R6:%.*]] = insertelement <8 x i32> [[R5]], i32 [[AB6]], i32 6
 ; CHECK-NEXT:    [[R7:%.*]] = insertelement <8 x i32> [[R6]], i32 [[AB7]], i32 7
 ; CHECK-NEXT:    ret <8 x i32> [[R7]]