diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -216,6 +216,16 @@
   if (type.getNumElements() == 0)
     return nullptr;
 
+  // Check that the raw data size matches what is expected for the scalar size.
+  // TODO: in theory, we could repack the data here to keep constructing from
+  // raw data.
+  // TODO: we may also need to consider endianness when cross-compiling to an
+  // architecture where it is different.
+  unsigned elementByteSize = denseElementsAttr.getRawData().size() /
+                             denseElementsAttr.getNumElements();
+  if (8 * elementByteSize != innermostLLVMType->getScalarSizeInBits())
+    return nullptr;
+
   // Compute the shape of all dimensions but the innermost. Note that the
   // innermost dimension may be that of the vector element type.
   bool hasVectorElementType = type.getElementType().isa<VectorType>();
diff --git a/mlir/test/Target/LLVMIR/llvmir.mlir b/mlir/test/Target/LLVMIR/llvmir.mlir
--- a/mlir/test/Target/LLVMIR/llvmir.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir.mlir
@@ -1251,6 +1251,20 @@
   llvm.return %1 : !llvm.array<2 x !llvm.array<2 x !llvm.struct<(i32, i32)>>>
 }
 
+// CHECK-LABEL: @indexconstantsplat
+llvm.func @indexconstantsplat() -> vector<3xi32> {
+  %1 = llvm.mlir.constant(dense<42> : vector<3xindex>) : vector<3xi32>
+  // CHECK: ret <3 x i32> <i32 42, i32 42, i32 42>
+  llvm.return %1 : vector<3xi32>
+}
+
+// CHECK-LABEL: @indexconstantarray
+llvm.func @indexconstantarray() -> vector<3xi32> {
+  %1 = llvm.mlir.constant(dense<[0, 1, 2]> : vector<3xindex>) : vector<3xi32>
+  // CHECK: ret <3 x i32> <i32 0, i32 1, i32 2> 
+  llvm.return %1 : vector<3xi32>
+}
+
 llvm.func @noreach() {
 // CHECK:    unreachable
   llvm.unreachable