diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1605,35 +1605,60 @@
 
   auto Unmerge = MIRBuilder.buildUnmerge(WideTy, WideSrc);
 
-  // Create a sequence of unmerges to the original results. since we may have
-  // widened the source, we will need to pad the results with dead defs to cover
-  // the source register.
-  // e.g. widen s16 to s32:
-  // %1:_(s16), %2:_(s16), %3:_(s16) = G_UNMERGE_VALUES %0:_(s48)
+  // Create a sequence of unmerges and merges to the original results. Since we
+  // may have widened the source, we will need to pad the results with dead defs
+  // to cover the source register.
+  // e.g. widen s48 to s64:
+  // %1:_(s48), %2:_(s48) = G_UNMERGE_VALUES %0:_(s96)
   //
   // =>
-  //  %4:_(s64) = G_ANYEXT %0:_(s48)
-  //  %5:_(s32), %6:_(s32) = G_UNMERGE_VALUES %4 ; Requested unmerge
-  //  %1:_(s16), %2:_(s16) = G_UNMERGE_VALUES %5 ; unpack to original regs
-  //  %3:_(s16), dead %7 = G_UNMERGE_VALUES %6 ; original reg + extra dead def
-
+  //  %4:_(s128) = G_ANYEXT %0:_(s96)
+  //  %5:_(s64), %6, %7 = G_UNMERGE_VALUES %4 ; Requested unmerge
+  //  ; unpack to GCD type, with extra dead defs
+  //  %8:_(s16), %9, %10, %11 = G_UNMERGE_VALUES %5:_(s64)
+  //  %12:_(s16), %13, dead %14, dead %15 = G_UNMERGE_VALUES %6:_(s64)
+  //  dead %16:_(s16), dead %17, dead %18, dead %18 = G_UNMERGE_VALUES %7:_(s64)
+  //  %1:_(s48) = G_MERGE_VALUES %8:_(s16), %9, %10   ; Remerge to destination
+  //  %2:_(s48) = G_MERGE_VALUES %11:_(s16), %12, %13 ; Remerge to destination
+  const LLT GCDTy = getGCDType(WideTy, DstTy);
   const int NumUnmerge = Unmerge->getNumOperands() - 1;
-  const int PartsPerUnmerge = WideTy.getSizeInBits() / DstTy.getSizeInBits();
-
-  for (int I = 0; I != NumUnmerge; ++I) {
-    auto MIB = MIRBuilder.buildInstr(TargetOpcode::G_UNMERGE_VALUES);
-
-    for (int J = 0; J != PartsPerUnmerge; ++J) {
-      int Idx = I * PartsPerUnmerge + J;
-      if (Idx < NumDst)
-        MIB.addDef(MI.getOperand(Idx).getReg());
-      else {
-        // Create dead def for excess components.
-        MIB.addDef(MRI.createGenericVirtualRegister(DstTy));
+  const int PartsPerRemerge = DstTy.getSizeInBits() / GCDTy.getSizeInBits();
+
+  // Directly unmerge to the destination without going through a GCD type
+  // if possible
+  if (PartsPerRemerge == 1) {
+    const int PartsPerUnmerge = WideTy.getSizeInBits() / DstTy.getSizeInBits();
+
+    for (int I = 0; I != NumUnmerge; ++I) {
+      auto MIB = MIRBuilder.buildInstr(TargetOpcode::G_UNMERGE_VALUES);
+
+      for (int J = 0; J != PartsPerUnmerge; ++J) {
+        int Idx = I * PartsPerUnmerge + J;
+        if (Idx < NumDst)
+          MIB.addDef(MI.getOperand(Idx).getReg());
+        else {
+          // Create dead def for excess components.
+          MIB.addDef(MRI.createGenericVirtualRegister(DstTy));
+        }
       }
+
+      MIB.addUse(Unmerge.getReg(I));
     }
+  } else {
+    SmallVector<Register, 16> Parts;
+    for (int J = 0; J != NumUnmerge; ++J)
+      extractGCDType(Parts, GCDTy, Unmerge.getReg(J));
+
+    SmallVector<Register, 4> RemergeParts;
+    for (int I = 0; I != NumDst; ++I) {
+      for (int J = 0; J < PartsPerRemerge; ++J) {
+        const int Idx = J + I * PartsPerRemerge;
+        RemergeParts.emplace_back(Parts[Idx]);
+      }
 
-    MIB.addUse(Unmerge.getReg(I));
+      MIRBuilder.buildMerge(MI.getOperand(I).getReg(), RemergeParts);
+      RemergeParts.clear();
+    }
   }
 
   MI.eraseFromParent();
diff --git a/llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp b/llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp
--- a/llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp
+++ b/llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp
@@ -3135,4 +3135,48 @@
   EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;
 }
 
+// Test fewer elements of G_INSERT_VECTOR_ELEMENT
+TEST_F(AArch64GISelMITest, widenScalarUnmerge) {
+  setUp();
+  if (!TM)
+    return;
+
+  DefineLegalizerInfo(A, {});
+
+  LLT S96{LLT::scalar(96)};
+  LLT S64{LLT::scalar(64)};
+  LLT S48{LLT::scalar(48)};
+
+  auto Src = B.buildAnyExt(S96, Copies[0]);
+  auto Unmerge = B.buildUnmerge(S48, Src);
+
+  AInfo Info(MF->getSubtarget());
+  DummyGISelObserver Observer;
+  LegalizerHelper Helper(*MF, Info, Observer, B);
+
+  // Perform Legalization
+  B.setInsertPt(*EntryMBB, Unmerge->getIterator());
+
+  // This should create unmerges to a GCD type (S16), then remerge to S48
+  EXPECT_EQ(LegalizerHelper::LegalizeResult::Legalized,
+            Helper.widenScalar(*Unmerge, 0, S64));
+
+  const auto *CheckStr = R"(
+  CHECK: [[COPY0:%[0-9]+]]:_(s64) = COPY
+  CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY
+  CHECK: [[COPY2:%[0-9]+]]:_(s64) = COPY
+  CHECK: [[ANYEXT:%[0-9]+]]:_(s96) = G_ANYEXT [[COPY0]]
+  CHECK: [[ANYEXT1:%[0-9]+]]:_(s192) = G_ANYEXT [[ANYEXT]]
+  CHECK: [[UNMERGE:%[0-9]+]]:_(s64), [[UNMERGE1:%[0-9]+]]:_(s64), [[UNMERGE2:%[0-9]+]]:_(s64) = G_UNMERGE_VALUES [[ANYEXT1]]
+  CHECK: [[UNMERGE3:%[0-9]+]]:_(s16), [[UNMERGE4:%[0-9]+]]:_(s16), [[UNMERGE5:%[0-9]+]]:_(s16), [[UNMERGE6:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[UNMERGE]]
+  CHECK: [[UNMERGE7:%[0-9]+]]:_(s16), [[UNMERGE8:%[0-9]+]]:_(s16), [[UNMERGE9:%[0-9]+]]:_(s16), [[UNMERGE10:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[UNMERGE1]]
+  CHECK: [[UNMERGE11:%[0-9]+]]:_(s16), [[UNMERGE12:%[0-9]+]]:_(s16), [[UNMERGE13:%[0-9]+]]:_(s16), [[UNMERGE14:%[0-9]+]]:_(s16) = G_UNMERGE_VALUES [[UNMERGE2]]
+  CHECK: [[MERGE:%[0-9]+]]:_(s48) = G_MERGE_VALUES [[UNMERGE3]]:_(s16), [[UNMERGE4]]:_(s16), [[UNMERGE5]]:_(s16)
+  CHECK: [[MERGE1:%[0-9]+]]:_(s48) = G_MERGE_VALUES [[UNMERGE6]]:_(s16), [[UNMERGE7]]:_(s16), [[UNMERGE8]]:_(s16)
+  )";
+
+  // Check
+  EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;
+}
+
 } // namespace