[Bug middle-end/37135] [4.3/4.4 Regression] code size increase for bit-fields assignment

["etienne_lorrain at yahoo dot fr" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from etienne_lorrain at yahoo dot fr  2008-08-17 19:31 -------
 It is not related to bitfields, this also show the problem:
struct color { unsigned char red, green, blue, transparent; } cur_color;
static const struct color mycolor = { 200, 10, 30, 0 };
void fct(void)
{
    cur_color = mycolor;
}
 with gcc-4.3.1 cur_color is initialised with 4 "movb" (so address is encoded 4
times)
 and with gcc-4.2 with a 32 bits constant and a single "movl".

 It seems to be the old problem of gcc not having a "write combining" pass
(converting consecutive byte/word writes into single double word writes), and
the "fix" of defining an intermediate variable is no more working.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37135