From: Eric Botcazou <ebotcazou@adacore.com>
To: Richard Guenther <richard.guenther@gmail.com>
Cc: Easwaran Raman <eraman@google.com>, gcc-patches@gcc.gnu.org
Subject: Re: Mark variables addressable if they are copied using libcall in RTL expander
Date: Wed, 22 Jun 2011 14:26:00 -0000 [thread overview]
Message-ID: <201106221613.09011.ebotcazou@adacore.com> (raw)
In-Reply-To: <BANLkTim2g4XqUMuM8YYrWjsjucwnuUbNqA@mail.gmail.com>
> 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
next prev parent reply other threads:[~2011-06-22 14:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-21 2:15 Easwaran Raman
2011-06-21 9:02 ` Richard Guenther
2011-06-22 13:15 ` Eric Botcazou
2011-06-22 13:53 ` Jakub Jelinek
2011-06-22 13:54 ` Richard Guenther
2011-06-22 14:26 ` Eric Botcazou [this message]
2011-06-22 19:39 ` Easwaran Raman
2011-06-23 10:00 ` Eric Botcazou
2011-06-23 10:32 ` Richard Guenther
2011-06-23 11:07 ` Eric Botcazou
2011-06-23 19:16 ` Easwaran Raman
2011-06-23 19:32 ` Jakub Jelinek
2011-06-23 21:56 ` Easwaran Raman
2011-06-24 9:00 ` Richard Guenther
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