Fix

Author: co63oc

paddle/phi/kernels/impl/matmul_kernel_impl.h

@@ -2002,6 +2002,7 @@ void MatmulKernel(const Context& ctx,
                   bool transpose_y,
                   DenseTensor* out) {
   if (x.numel() == 0 || y.numel() == 0) {
+    // input shape [1, 1, 5, 0], [1, 1, 0, 5], result shape is [1, 1, 5, 5]
     phi::Full<T, Context>(
         ctx, phi::IntArray(common::vectorize(out->dims())), 0, out);
     return;