Function alloc 

pub fn alloc<'c>(
    context: &'c Context,
    type: MemRefType<'c>,
    dynamic_sizes: &[Value<'c, '_>],
    symbols: &[Value<'c, '_>],
    alignment: Option<IntegerAttribute<'c>>,
    location: Location<'c>,
) -> Operation<'c>

Create a memref.alloc operation.