diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2630,12 +2630,13 @@
 
       Type *SelectorTy = Type::getInt1Ty(Context);
 
-      // The selector might be an i1 or an <n x i1>
+      // The selector might be an i1, an <n x i1>, or a <vscale x n x i1>
       // Get the type from the ValueList before getting a forward ref.
       if (VectorType *VTy = dyn_cast<VectorType>(CurTy))
         if (Value *V = ValueList[Record[0]])
           if (SelectorTy != V->getType())
-            SelectorTy = VectorType::get(SelectorTy, VTy->getNumElements());
+            SelectorTy = VectorType::get(SelectorTy,
+                                         VTy->getElementCount());
 
       V = ConstantExpr::getSelect(ValueList.getConstantFwdRef(Record[0],
                                                               SelectorTy),
@@ -2693,7 +2694,7 @@
       Constant *Op0 = ValueList.getConstantFwdRef(Record[0], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
-                                                 OpTy->getNumElements());
+                                     OpTy->getElementCount());
       Constant *Op2 = ValueList.getConstantFwdRef(Record[2], ShufTy);
       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
       break;
@@ -2707,7 +2708,7 @@
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
       Type *ShufTy = VectorType::get(Type::getInt32Ty(Context),
-                                                 RTy->getNumElements());
+                                     RTy->getElementCount());
       Constant *Op2 = ValueList.getConstantFwdRef(Record[3], ShufTy);
       V = ConstantExpr::getShuffleVector(Op0, Op1, Op2);
       break;
@@ -4168,9 +4169,15 @@
         return error("Invalid record");
       if (!Vec1->getType()->isVectorTy() || !Vec2->getType()->isVectorTy())
         return error("Invalid type for value");
+
+      ElementCount EC1 = cast<VectorType>(Vec1->getType())->getElementCount();
+
+      if (EC1 != cast<VectorType>(Vec2->getType())->getElementCount())
+        return error("Mismatch between argument types");
+
       I = new ShuffleVectorInst(Vec1, Vec2, Mask);
       FullTy = VectorType::get(FullTy->getVectorElementType(),
-                               Mask->getType()->getVectorNumElements());
+                               EC1);
       InstructionList.push_back(I);
       break;
     }
diff --git a/llvm/test/Bitcode/vscale-round-trip.ll b/llvm/test/Bitcode/vscale-round-trip.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Bitcode/vscale-round-trip.ll
@@ -0,0 +1,49 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64"
+
+@important_val = extern_weak dso_local global i32, align 4
+
+; CHECK-LABEL: define <vscale x 4 x i32> @const_shufflevector(
+; CHECK: <vscale x 4 x i32> shufflevector (<vscale x 4 x i32>
+
+define <vscale x 4 x i32> @const_shufflevector() {
+  ret <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> zeroinitializer,
+                                        <vscale x 4 x i32> undef,
+                                        <vscale x 4 x i32> zeroinitializer)
+}
+
+; CHECK-LABEL: define <vscale x 4 x i32> @const_shufflevector_ex()
+; CHECK: <vscale x 4 x i32> shufflevector (<vscale x 2 x i32>
+
+define <vscale x 4 x i32> @const_shufflevector_ex() {
+  ret <vscale x 4 x i32> shufflevector (<vscale x 2 x i32> zeroinitializer,
+                                        <vscale x 2 x i32> undef,
+                                        <vscale x 4 x i32> zeroinitializer)
+}
+
+; CHECK-LABEL: define <vscale x 4 x i32> @non_const_shufflevector(
+; CHECK: %res = shufflevector <vscale x 4 x i32>
+
+define <vscale x 4 x i32> @non_const_shufflevector(<vscale x 4 x i32> %lhs,
+                                                   <vscale x 4 x i32> %rhs) {
+  %res = shufflevector <vscale x 4 x i32> %lhs,
+                       <vscale x 4 x i32> %rhs,
+                       <vscale x 4 x i32> zeroinitializer
+
+  ret <vscale x 4 x i32> %res
+}
+
+; CHECK-LABEL: define <vscale x 4 x i32> @const_select()
+; CHECK: <vscale x 4 x i32> select (<vscale x 4 x i1>
+
+define <vscale x 4 x i32> @const_select() {
+  ret <vscale x 4 x i32> select
+    (<vscale x 4 x i1> insertelement
+      (<vscale x 4 x i1> undef,
+       i1 icmp ne (i32* @important_val, i32* null),
+       i32 0),
+     <vscale x 4 x i32> zeroinitializer,
+     <vscale x 4 x i32> insertelement (<vscale x 4 x i32> undef, i32 1, i32 0))
+}