g_new0 performance

Submitted by Morten Welinder

Description

g_new0 is very often called with a constant object count, notably one. Therefore, the total size if often known at compile time and the compiler ought to be able to zero the structure in a smarter way that just memset.

Unfortunately, g_new0 is implemented in terms of g_malloc0 so the size knowledge is tossed away, :-(

For gcc, something like this ought to work:

#define g_new0(struct_type, n_structs)
({ gsize _gnew0_size = sizeof (struct_type) * (n_structs); struct_type *_gnew0_res = g_malloc (_gnew0_size); memset (_gnew0_res, 0, _gnew0_size); _gnew0_res; })