Index: lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -798,6 +798,7 @@
   SDValue WidenVecOp_EXTRACT_SUBVECTOR(SDNode *N);
   SDValue WidenVecOp_STORE(SDNode* N);
   SDValue WidenVecOp_MSTORE(SDNode* N, unsigned OpNo);
+  SDValue WidenVecOp_MGATHER(SDNode* N, unsigned OpNo);
   SDValue WidenVecOp_MSCATTER(SDNode* N, unsigned OpNo);
   SDValue WidenVecOp_SETCC(SDNode* N);
 
Index: lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -3633,6 +3633,7 @@
   case ISD::EXTRACT_VECTOR_ELT: Res = WidenVecOp_EXTRACT_VECTOR_ELT(N); break;
   case ISD::STORE:              Res = WidenVecOp_STORE(N); break;
   case ISD::MSTORE:             Res = WidenVecOp_MSTORE(N, OpNo); break;
+  case ISD::MGATHER:            Res = WidenVecOp_MGATHER(N, OpNo); break;
   case ISD::MSCATTER:           Res = WidenVecOp_MSCATTER(N, OpNo); break;
   case ISD::SETCC:              Res = WidenVecOp_SETCC(N); break;
   case ISD::FCOPYSIGN:          Res = WidenVecOp_FCOPYSIGN(N); break;
@@ -3898,36 +3899,86 @@
                             false, MST->isCompressingStore());
 }
 
-SDValue DAGTypeLegalizer::WidenVecOp_MSCATTER(SDNode *N, unsigned OpNo) {
-  assert(OpNo == 1 && "Can widen only data operand of mscatter");
-  MaskedScatterSDNode *MSC = cast<MaskedScatterSDNode>(N);
-  SDValue DataOp = MSC->getValue();
-  SDValue Mask = MSC->getMask();
+SDValue DAGTypeLegalizer::WidenVecOp_MGATHER(SDNode *N, unsigned OpNo) {
+  assert(OpNo == 4 && "Can widen only the index of mgather");
+  auto *MG = cast<MaskedGatherSDNode>(N);
+  SDValue DataOp = MG->getPassThru();
+  SDValue Mask = MG->getMask();
+  SDValue Scale = MG->getScale();
   EVT MaskVT = Mask.getValueType();
-  SDValue Scale = MSC->getScale();
+  EVT DataVT = DataOp.getValueType();
+
+  // Widen index.
+  SDValue Index = GetWidenedVector(MG->getIndex());
+  unsigned NumElts = Index.getValueType().getVectorNumElements();
 
   // Widen the value.
-  SDValue WideVal = GetWidenedVector(DataOp);
-  EVT WideVT = WideVal.getValueType();
-  unsigned NumElts = WideVT.getVectorNumElements();
-  SDLoc dl(N);
+  EVT WideDataVT = EVT::getVectorVT(*DAG.getContext(),
+                                    DataVT.getVectorElementType(),
+                                    NumElts);
+  DataOp = ModifyToType(DataOp, WideDataVT);
 
   // The mask should be widened as well.
   EVT WideMaskVT = EVT::getVectorVT(*DAG.getContext(),
                                     MaskVT.getVectorElementType(), NumElts);
   Mask = ModifyToType(Mask, WideMaskVT, true);
 
-  // Widen index.
+  SDLoc dl(N);
+  SDValue Ops[] = {MG->getChain(), DataOp, Mask, MG->getBasePtr(), Index,
+                   Scale};
+  SDValue Res = DAG.getMaskedGather(DAG.getVTList(WideDataVT, MVT::Other),
+                                    MG->getMemoryVT(), dl, Ops,
+                                    MG->getMemOperand());
+  ReplaceValueWith(SDValue(N, 1), Res.getValue(1));
+
+  Res = DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, N->getValueType(0), Res,
+                    DAG.getConstant(0, dl,
+                                    TLI.getVectorIdxTy(DAG.getDataLayout())));
+
+  ReplaceValueWith(SDValue(N, 0), Res.getValue(0));
+  return SDValue();
+}
+
+SDValue DAGTypeLegalizer::WidenVecOp_MSCATTER(SDNode *N, unsigned OpNo) {
+  MaskedScatterSDNode *MSC = cast<MaskedScatterSDNode>(N);
+  SDValue DataOp = MSC->getValue();
+  SDValue Mask = MSC->getMask();
   SDValue Index = MSC->getIndex();
-  EVT WideIndexVT = EVT::getVectorVT(*DAG.getContext(),
-                                     Index.getValueType().getScalarType(),
-                                     NumElts);
-  Index = ModifyToType(Index, WideIndexVT);
+  SDValue Scale = MSC->getScale();
 
-  SDValue Ops[] = {MSC->getChain(), WideVal, Mask, MSC->getBasePtr(), Index,
+  unsigned NumElts;
+  if (OpNo == 1) {
+    DataOp = GetWidenedVector(DataOp);
+    NumElts = DataOp.getValueType().getVectorNumElements();
+
+    // Widen index.
+    EVT IndexVT = Index.getValueType();
+    EVT WideIndexVT = EVT::getVectorVT(*DAG.getContext(),
+                                       IndexVT.getVectorElementType(), NumElts);
+
+    Index = ModifyToType(Index, WideIndexVT);
+  } else if (OpNo == 4) {
+    Index = GetWidenedVector(Index);
+    NumElts = Index.getValueType().getVectorNumElements();
+
+    // Widen the data.
+    EVT DataVT = DataOp.getValueType();
+    EVT WideDataVT = EVT::getVectorVT(*DAG.getContext(),
+                                      DataVT.getVectorElementType(), NumElts);
+    DataOp = ModifyToType(DataOp, WideDataVT);
+  } else
+    llvm_unreachable("Can't widen this operand of mscatter");
+
+  // The mask should be widened as well.
+  EVT MaskVT = Mask.getValueType();
+  EVT WideMaskVT = EVT::getVectorVT(*DAG.getContext(),
+                                    MaskVT.getVectorElementType(), NumElts);
+
+  Mask = ModifyToType(Mask, WideMaskVT, true);
+  SDValue Ops[] = {MSC->getChain(), DataOp, Mask, MSC->getBasePtr(), Index,
                    Scale};
   return DAG.getMaskedScatter(DAG.getVTList(MVT::Other),
-                              MSC->getMemoryVT(), dl, Ops,
+                              MSC->getMemoryVT(), SDLoc(N), Ops,
                               MSC->getMemOperand());
 }
 
Index: test/CodeGen/X86/masked_gather_scatter_widen.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/masked_gather_scatter_widen.ll
@@ -0,0 +1,140 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=+avx512vl -mattr=+avx512dq -x86-experimental-vector-widening-legalization < %s | FileCheck %s --check-prefix=CHECK --check-prefix=WIDEN
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -mattr=+avx512vl -mattr=+avx512dq < %s | FileCheck %s --check-prefix=CHECK --check-prefix=PROMOTE
+
+define <2 x double> @test_gather_v2i32_index(double* %base, <2 x i32> %ind, <2 x i1> %mask, <2 x double> %src0) {
+; WIDEN-LABEL: test_gather_v2i32_index:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    # kill: def $xmm2 killed $xmm2 def $ymm2
+; WIDEN-NEXT:    vpsllq $63, %xmm1, %xmm1
+; WIDEN-NEXT:    vpmovq2m %xmm1, %k1
+; WIDEN-NEXT:    vgatherdpd (%rdi,%xmm0,8), %ymm2 {%k1}
+; WIDEN-NEXT:    vmovapd %xmm2, %xmm0
+; WIDEN-NEXT:    vzeroupper
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_gather_v2i32_index:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $32, %xmm0, %xmm0
+; PROMOTE-NEXT:    vpsraq $32, %xmm0, %xmm0
+; PROMOTE-NEXT:    vpsllq $63, %xmm1, %xmm1
+; PROMOTE-NEXT:    vpmovq2m %xmm1, %k1
+; PROMOTE-NEXT:    vgatherqpd (%rdi,%xmm0,8), %xmm2 {%k1}
+; PROMOTE-NEXT:    vmovapd %xmm2, %xmm0
+; PROMOTE-NEXT:    retq
+  %gep.random = getelementptr double, double* %base, <2 x i32> %ind
+  %res = call <2 x double> @llvm.masked.gather.v2f64.v2p0f64(<2 x double*> %gep.random, i32 4, <2 x i1> %mask, <2 x double> %src0)
+  ret <2 x double> %res
+}
+
+define void @test_scatter_v2i32_index(<2 x double> %a1, double* %base, <2 x i32> %ind, <2 x i1> %mask) {
+; WIDEN-LABEL: test_scatter_v2i32_index:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    # kill: def $xmm0 killed $xmm0 def $ymm0
+; WIDEN-NEXT:    vpsllq $63, %xmm2, %xmm2
+; WIDEN-NEXT:    vpmovq2m %xmm2, %k1
+; WIDEN-NEXT:    vscatterdpd %ymm0, (%rdi,%xmm1,8) {%k1}
+; WIDEN-NEXT:    vzeroupper
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_scatter_v2i32_index:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $63, %xmm2, %xmm2
+; PROMOTE-NEXT:    vpmovq2m %xmm2, %k1
+; PROMOTE-NEXT:    vpsllq $32, %xmm1, %xmm1
+; PROMOTE-NEXT:    vpsraq $32, %xmm1, %xmm1
+; PROMOTE-NEXT:    vscatterqpd %xmm0, (%rdi,%xmm1,8) {%k1}
+; PROMOTE-NEXT:    retq
+  %gep = getelementptr double, double *%base, <2 x i32> %ind
+  call void @llvm.masked.scatter.v2f64.v2p0f64(<2 x double> %a1, <2 x double*> %gep, i32 4, <2 x i1> %mask)
+  ret void
+}
+
+define <2 x i32> @test_gather_v2i32_data(<2 x i32*> %ptr, <2 x i1> %mask, <2 x i32> %src0) {
+; WIDEN-LABEL: test_gather_v2i32_data:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    vpsllq $63, %xmm1, %xmm1
+; WIDEN-NEXT:    vpmovq2m %xmm1, %k1
+; WIDEN-NEXT:    vpgatherqd (,%xmm0), %xmm2 {%k1}
+; WIDEN-NEXT:    vmovdqa %xmm2, %xmm0
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_gather_v2i32_data:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $63, %xmm1, %xmm1
+; PROMOTE-NEXT:    vpmovq2m %xmm1, %k1
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm1 = xmm2[0,2,2,3]
+; PROMOTE-NEXT:    vpgatherqd (,%xmm0), %xmm1 {%k1}
+; PROMOTE-NEXT:    vpmovzxdq {{.*#+}} xmm0 = xmm1[0],zero,xmm1[1],zero
+; PROMOTE-NEXT:    retq
+  %res = call <2 x i32> @llvm.masked.gather.v2i32.v2p0i32(<2 x i32*> %ptr, i32 4, <2 x i1> %mask, <2 x i32> %src0)
+  ret <2 x i32>%res
+}
+
+define void @test_scatter_v2i32_data(<2 x i32>%a1, <2 x i32*> %ptr, <2 x i1>%mask) {
+; WIDEN-LABEL: test_scatter_v2i32_data:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    vpsllq $63, %xmm2, %xmm2
+; WIDEN-NEXT:    vpmovq2m %xmm2, %k1
+; WIDEN-NEXT:    vpscatterqd %xmm0, (,%xmm1) {%k1}
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_scatter_v2i32_data:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $63, %xmm2, %xmm2
+; PROMOTE-NEXT:    vpmovq2m %xmm2, %k1
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
+; PROMOTE-NEXT:    vpscatterqd %xmm0, (,%xmm1) {%k1}
+; PROMOTE-NEXT:    retq
+  call void @llvm.masked.scatter.v2i32.v2p0i32(<2 x i32> %a1, <2 x i32*> %ptr, i32 4, <2 x i1> %mask)
+  ret void
+}
+
+define <2 x i32> @test_gather_v2i32_data_index(i32* %base, <2 x i32> %ind, <2 x i1> %mask, <2 x i32> %src0) {
+; WIDEN-LABEL: test_gather_v2i32_data_index:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    vpsllq $63, %xmm1, %xmm1
+; WIDEN-NEXT:    vpmovq2m %xmm1, %k1
+; WIDEN-NEXT:    vpgatherdd (%rdi,%xmm0,4), %xmm2 {%k1}
+; WIDEN-NEXT:    vmovdqa %xmm2, %xmm0
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_gather_v2i32_data_index:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $63, %xmm1, %xmm1
+; PROMOTE-NEXT:    vpmovq2m %xmm1, %k1
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm1 = xmm2[0,2,2,3]
+; PROMOTE-NEXT:    vpgatherdd (%rdi,%xmm0,4), %xmm1 {%k1}
+; PROMOTE-NEXT:    vpmovzxdq {{.*#+}} xmm0 = xmm1[0],zero,xmm1[1],zero
+; PROMOTE-NEXT:    retq
+  %gep.random = getelementptr i32, i32* %base, <2 x i32> %ind
+  %res = call <2 x i32> @llvm.masked.gather.v2i32.v2p0i32(<2 x i32*> %gep.random, i32 4, <2 x i1> %mask, <2 x i32> %src0)
+  ret <2 x i32> %res
+}
+
+define void @test_scatter_v2i32_data_index(<2 x i32> %a1, i32* %base, <2 x i32> %ind, <2 x i1> %mask) {
+; WIDEN-LABEL: test_scatter_v2i32_data_index:
+; WIDEN:       # %bb.0:
+; WIDEN-NEXT:    vpsllq $63, %xmm2, %xmm2
+; WIDEN-NEXT:    vpmovq2m %xmm2, %k1
+; WIDEN-NEXT:    vpscatterdd %xmm0, (%rdi,%xmm1,4) {%k1}
+; WIDEN-NEXT:    retq
+;
+; PROMOTE-LABEL: test_scatter_v2i32_data_index:
+; PROMOTE:       # %bb.0:
+; PROMOTE-NEXT:    vpsllq $63, %xmm2, %xmm2
+; PROMOTE-NEXT:    vpmovq2m %xmm2, %k1
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
+; PROMOTE-NEXT:    vpshufd {{.*#+}} xmm1 = xmm1[0,2,2,3]
+; PROMOTE-NEXT:    vpscatterdd %xmm0, (%rdi,%xmm1,4) {%k1}
+; PROMOTE-NEXT:    retq
+  %gep = getelementptr i32, i32 *%base, <2 x i32> %ind
+  call void @llvm.masked.scatter.v2i32.v2p0i32(<2 x i32> %a1, <2 x i32*> %gep, i32 4, <2 x i1> %mask)
+  ret void
+}
+
+declare <2 x double> @llvm.masked.gather.v2f64.v2p0f64(<2 x double*>, i32, <2 x i1>, <2 x double>)
+declare void @llvm.masked.scatter.v2f64.v2p0f64(<2 x double>, <2 x double*>, i32, <2 x i1>)
+declare <2 x i32> @llvm.masked.gather.v2i32.v2p0i32(<2 x i32*>, i32, <2 x i1>, <2 x i32>)
+declare void @llvm.masked.scatter.v2i32.v2p0i32(<2 x i32> , <2 x i32*> , i32 , <2 x i1>)