> I fear this isn't enough considering pass-by-value aggregates that
> are callee copied.
It's indeed not sufficient for arguments passed by reference but callee-copied.
This is PR target/49454. For gcc.c-torture/execute/20000717-1.c:
typedef struct trio { int a, b, c; } trio;
int
foo (trio t, int i)
{
return bar (i, t);
}
yiedls in the .optimized dump:
foo (struct trio t, int i)
{
int D.1968;
struct trio t.0;
<bb 2>:
t.0 = t;
D.1968_2 = bar (i_1(D), t.0);
return D.1968_2;
}
and the aggregate copy is elided by DSE because t.0 isn't may_be_aliased. This
seems to be a pre-existing bug though: its address is passed to bar in RTL.
--
Eric Botcazou
