Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3951,9 +3951,8 @@
       Type *OriginalTy = I->getType();
       Type *ScalarTruncatedTy =
           IntegerType::get(OriginalTy->getContext(), KV.second);
-      auto *TruncatedTy = FixedVectorType::get(
-          ScalarTruncatedTy,
-          cast<FixedVectorType>(OriginalTy)->getNumElements());
+      auto *TruncatedTy = VectorType::get(
+          ScalarTruncatedTy, cast<VectorType>(OriginalTy)->getElementCount());
       if (TruncatedTy == OriginalTy)
         continue;
 
Index: llvm/test/Transforms/LoopVectorize/scalable-trunc-min-bitwidth.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LoopVectorize/scalable-trunc-min-bitwidth.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -loop-vectorize -scalable-vectorization=on -force-target-supports-scalable-vectors -S | FileCheck %s
+
+define void @trunc_minimal_bitwidth(i8* %bptr, i16* %hptr, i32 %sptr, i64 %dptr) {
+; CHECK-LABEL: @trunc_minimal_bitwidth(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[INDVARS_IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[INDVARS_IV_NEXT:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = load i8, i8* [[BPTR:%.*]], align 1
+; CHECK-NEXT:    [[CONV:%.*]] = zext i8 [[TMP0]] to i32
+; CHECK-NEXT:    [[CONV21:%.*]] = trunc i32 [[SPTR:%.*]] to i16
+; CHECK-NEXT:    [[ARRAYIDX23:%.*]] = getelementptr inbounds i16, i16* [[HPTR:%.*]], i64 [[INDVARS_IV]]
+; CHECK-NEXT:    store i16 [[CONV21]], i16* [[ARRAYIDX23]], align 2
+; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
+; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_IV_NEXT]], [[DPTR:%.*]]
+; CHECK-NEXT:    br label [[FOR_BODY]]
+entry:
+  br label %for.body
+
+for.body:                                             ; preds = %for.body.pre, %for.body
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %0 = load i8, i8* %bptr, align 1
+  %conv = zext i8 %0 to i32
+  %conv21 = trunc i32 %sptr to i16
+  %arrayidx23 = getelementptr inbounds i16, i16* %hptr, i64 %indvars.iv
+  store i16 %conv21, i16* %arrayidx23, align 2
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond.not = icmp eq i64 %indvars.iv.next, %dptr
+  br label %for.body
+}