diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -9691,7 +9691,8 @@
 The first operand of an '``extractelement``' instruction is a value of
 :ref:`vector <t_vector>` type. The second operand is an index indicating
 the position from which to extract the element. The index may be a
-variable of any integer type.
+variable of any integer type, and will be zero extended or truncated 
+depending on the target.
 
 Semantics:
 """"""""""
@@ -9736,7 +9737,8 @@
 :ref:`vector <t_vector>` type. The second operand is a scalar value whose
 type must equal the element type of the first operand. The third operand
 is an index indicating the position at which to insert the value. The
-index may be a variable of any integer type.
+index may be a variable of any integer type, and will be zero extended or 
+truncated depending on the target.
 
 Semantics:
 """"""""""
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2808,7 +2808,7 @@
   Register Idx;
   if (auto *CI = dyn_cast<ConstantInt>(U.getOperand(1))) {
     if (CI->getBitWidth() != PreferredVecIdxWidth) {
-      APInt NewIdx = CI->getValue().sextOrTrunc(PreferredVecIdxWidth);
+      APInt NewIdx = CI->getValue().zextOrTrunc(PreferredVecIdxWidth);
       auto *NewIdxCI = ConstantInt::get(CI->getContext(), NewIdx);
       Idx = getOrCreateVReg(*NewIdxCI);
     }
@@ -2817,7 +2817,7 @@
     Idx = getOrCreateVReg(*U.getOperand(1));
   if (MRI->getType(Idx).getSizeInBits() != PreferredVecIdxWidth) {
     const LLT VecIdxTy = LLT::scalar(PreferredVecIdxWidth);
-    Idx = MIRBuilder.buildSExtOrTrunc(VecIdxTy, Idx).getReg(0);
+    Idx = MIRBuilder.buildZExtOrTrunc(VecIdxTy, Idx).getReg(0);
   }
   MIRBuilder.buildExtractVectorElement(Res, Val, Idx);
   return true;
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -3545,7 +3545,7 @@
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDValue InVec = getValue(I.getOperand(0));
   SDValue InVal = getValue(I.getOperand(1));
-  SDValue InIdx = DAG.getSExtOrTrunc(getValue(I.getOperand(2)), getCurSDLoc(),
+  SDValue InIdx = DAG.getZExtOrTrunc(getValue(I.getOperand(2)), getCurSDLoc(),
                                      TLI.getVectorIdxTy(DAG.getDataLayout()));
   setValue(&I, DAG.getNode(ISD::INSERT_VECTOR_ELT, getCurSDLoc(),
                            TLI.getValueType(DAG.getDataLayout(), I.getType()),
@@ -3555,7 +3555,7 @@
 void SelectionDAGBuilder::visitExtractElement(const User &I) {
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDValue InVec = getValue(I.getOperand(0));
-  SDValue InIdx = DAG.getSExtOrTrunc(getValue(I.getOperand(1)), getCurSDLoc(),
+  SDValue InIdx = DAG.getZExtOrTrunc(getValue(I.getOperand(1)), getCurSDLoc(),
                                      TLI.getVectorIdxTy(DAG.getDataLayout()));
   setValue(&I, DAG.getNode(ISD::EXTRACT_VECTOR_ELT, getCurSDLoc(),
                            TLI.getValueType(DAG.getDataLayout(), I.getType()),
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
--- a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -1549,7 +1549,7 @@
 ; CHECK-LABEL: name: test_extractelement
 ; CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = COPY $d0
 ; CHECK: [[IDX:%[0-9]+]]:_(s32) = COPY $w0
-; CHECK: [[IDXEXT:%[0-9]+]]:_(s64) = G_SEXT [[IDX]]
+; CHECK: [[IDXEXT:%[0-9]+]]:_(s64) = G_ZEXT [[IDX]]
 ; CHECK: [[RES:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[VEC]](<2 x s32>), [[IDXEXT]](s64)
 ; CHECK: $w0 = COPY [[RES]](s32)
   %res = extractelement <2 x i32> %vec, i32 %idx
@@ -1566,6 +1566,27 @@
   ret i32 %res
 }
 
+define i32 @test_extractelement_const_idx_zext_i1(<2 x i32> %vec) {
+; CHECK-LABEL: name: test_extractelement
+; CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = COPY $d0
+; CHECK: [[IDX:%[0-9]+]]:_(s64) = G_CONSTANT i64 1
+; CHECK: [[RES:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[VEC]](<2 x s32>), [[IDX]](s64)
+; CHECK: $w0 = COPY [[RES]](s32)
+  %res = extractelement <2 x i32> %vec, i1 true
+  ret i32 %res
+}
+
+define i32 @test_extractelement_const_idx_zext_i8(<2 x i32> %vec) {
+; CHECK-LABEL: name: test_extractelement
+; CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = COPY $d0
+; CHECK: [[IDX:%[0-9]+]]:_(s64) = G_CONSTANT i64 255
+; CHECK: [[RES:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[VEC]](<2 x s32>), [[IDX]](s64)
+; CHECK: $w0 = COPY [[RES]](s32)
+  %res = extractelement <2 x i32> %vec, i8 255
+  ret i32 %res
+}
+
+
 define i32 @test_singleelementvector(i32 %elt){
 ; CHECK-LABEL: name: test_singleelementvector
 ; CHECK: [[ELT:%[0-9]+]]:_(s32) = COPY $w0
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-zext-vec-index.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-zext-vec-index.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-zext-vec-index.ll
@@ -0,0 +1,28 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc -march=amdgcn -O0 -stop-after=irtranslator -global-isel -verify-machineinstrs %s -o - | FileCheck %s
+
+define i8 @f_i1_1() {
+  ; CHECK-LABEL: name: f_i1_1
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK-NEXT:   [[DEF:%[0-9]+]]:_(<256 x s8>) = G_IMPLICIT_DEF
+  ; CHECK-NEXT:   [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+  ; CHECK-NEXT:   [[EVEC:%[0-9]+]]:_(s8) = G_EXTRACT_VECTOR_ELT [[DEF]](<256 x s8>), [[C]](s32)
+  ; CHECK-NEXT:   [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[EVEC]](s8)
+  ; CHECK-NEXT:   $vgpr0 = COPY [[ANYEXT]](s32)
+  ; CHECK-NEXT:   SI_RETURN implicit $vgpr0
+  %E1 = extractelement <256 x i8> undef, i1 true
+  ret i8 %E1
+}
+
+define i8 @f_i8_255() {
+  ; CHECK-LABEL: name: f_i8_255
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK-NEXT:   [[DEF:%[0-9]+]]:_(<256 x s8>) = G_IMPLICIT_DEF
+  ; CHECK-NEXT:   [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 255
+  ; CHECK-NEXT:   [[EVEC:%[0-9]+]]:_(s8) = G_EXTRACT_VECTOR_ELT [[DEF]](<256 x s8>), [[C]](s32)
+  ; CHECK-NEXT:   [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[EVEC]](s8)
+  ; CHECK-NEXT:   $vgpr0 = COPY [[ANYEXT]](s32)
+  ; CHECK-NEXT:   SI_RETURN implicit $vgpr0
+  %E1 = extractelement <256 x i8> undef, i8 255
+  ret i8 %E1
+}