Index: mlir/lib/Dialect/Vector/Transforms/VectorTransforms.cpp
===================================================================
--- mlir/lib/Dialect/Vector/Transforms/VectorTransforms.cpp
+++ mlir/lib/Dialect/Vector/Transforms/VectorTransforms.cpp
@@ -1324,6 +1324,12 @@
   if (!elementType.isIntOrFloat())
     return failure();
 
+  Type dstElementType = op.getType();
+  if (auto vecType = dstElementType.dyn_cast<VectorType>())
+    dstElementType = vecType.getElementType();
+  if (elementType != dstElementType)
+    return failure();
+
   // Perform lhs + rhs transpositions to conform to matmul row-major semantics.
   // Bail out if the contraction cannot be put in this form.
   MLIRContext *ctx = op.getContext();
@@ -1416,11 +1422,29 @@
     return builder.create<vector::TransposeOp>(loc, v, perm);
   }
 
+  Value promote(Value v, Type dstElementType) {
+    Type elementType = v.getType();
+    auto vecType = elementType.dyn_cast<VectorType>();
+    if (vecType)
+      elementType = vecType.getElementType();
+    if (elementType == dstElementType)
+      return v;
+    Type promotedType = dstElementType;
+    if (vecType)
+      promotedType = VectorType::get(vecType.getShape(), promotedType);
+    if (dstElementType.isa<FloatType>())
+      return builder.create<arith::ExtFOp>(loc, promotedType, v);
+    return builder.create<arith::ExtSIOp>(loc, promotedType, v);
+  }
+
   Value outerProd(Value lhs, Value rhs, Value res, int reductionSize) {
     assert(reductionSize > 0);
+    Type resElementType = res.getType().cast<VectorType>().getElementType();
     for (int64_t k = 0; k < reductionSize; ++k) {
       Value a = builder.create<vector::ExtractOp>(loc, lhs, k);
       Value b = builder.create<vector::ExtractOp>(loc, rhs, k);
+      a = promote(a, resElementType);
+      b = promote(b, resElementType);
       res = builder.create<vector::OuterProductOp>(loc, res.getType(), a, b,
                                                    res, kind);
     }
Index: mlir/test/Dialect/Vector/vector-contract-transforms.mlir
===================================================================
--- mlir/test/Dialect/Vector/vector-contract-transforms.mlir
+++ mlir/test/Dialect/Vector/vector-contract-transforms.mlir
@@ -891,6 +891,25 @@
   return %0 : vector<2x3xf32>
 }
 
+// OUTERPRODUCT-LABEL: func @matmul_0
+// OUTERPRODUCT-SAME: %[[A:[a-zA-Z0-9]*]]: vector<2x1xf16>,
+// OUTERPRODUCT-SAME: %[[B:[a-zA-Z0-9]*]]: vector<1x3xf16>,
+// OUTERPRODUCT-SAME: %[[C:[a-zA-Z0-9]*]]: vector<2x3xf32>
+//      OUTERPRODUCT: %[[At:.*]] = vector.transpose %[[A]], [1, 0]
+//      OUTERPRODUCT: %[[a0:.*]] = vector.extract %[[At]][0] : vector<1x2xf16>
+//      OUTERPRODUCT: %[[b0:.*]] = vector.extract %[[B]][0] : vector<1x3xf16>
+//      OUTERPRODUCT: %[[a1:.*]] = arith.extf %[[a0]] : vector<2xf16> to vector<2xf32>
+//      OUTERPRODUCT: %[[b1:.*]] = arith.extf %[[b0]] : vector<3xf16> to vector<3xf32>
+//      OUTERPRODUCT: %[[c0:.*]] = vector.outerproduct %[[a1]], %[[b1]], %[[C]]
+//      OUTERPRODUCT: return %[[c0]] : vector<2x3xf32>
+func.func @matmul_0_mixed(%arg0: vector<2x1xf16>, %arg1: vector<1x3xf16>, %arg2: vector<2x3xf32>)
+-> vector<2x3xf32>
+{
+  %0 = vector.contract #matmat_trait_0 %arg0, %arg1, %arg2
+    : vector<2x1xf16>, vector<1x3xf16> into vector<2x3xf32>
+  return %0 : vector<2x3xf32>
+}
+
 #matmat_accesses_1 = [
   affine_map<(m, n, k) -> (m, k)>,
   affine_map<(m, n, k) -> (n, k)>,