From: Eric Botcazou <ebotcazou@libertysurf.fr>
To: Ian Lance Taylor <iant@google.com>
Cc: gcc-patches@gcc.gnu.org,
Kenneth Zadeck <zadeck@naturalbridge.com>,
Uros Bizjak <ubizjak@gmail.com>
Subject: Re: [PATCH, rtl-optimization]: Fix PR rtl-optimization/33638
Date: Mon, 15 Oct 2007 07:43:00 -0000 [thread overview]
Message-ID: <200710150804.42107.ebotcazou@libertysurf.fr> (raw)
In-Reply-To: <m3y7e5oy32.fsf@localhost.localdomain>
> Note that a const call only reads the frame if there is a MEM in
> CALL_INSN_FUNCTION_USAGE. On many platforms a const call will not
> normally read the frame.
Sure, that's what is explained at the beginning of the big comment. Note that
the DSE from flow.c did the same (invalidate all stack pointer based stores).
> I have the feeling that your previous patch has more or less wiped out
> DSE for const calls. Does DSE still actually eliminate any stores in
> the presence of a const call?
Definitely, the patch doesn't change anything for stores with constant base:
__attribute__ ((const)) int f (int i) { return i; }
int a;
void g (void)
{
a = 1;
a = f(0);
}
Compile at -O -fno-tree-dse.
--
Eric Botcazou
next prev parent reply other threads:[~2007-10-15 6:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-08 12:14 Uros Bizjak
2007-10-08 12:35 ` [Bug rtl-optimization/33638] [4.3 regression]: wrong code with -fforce-addr Kenneth Zadeck
2007-10-09 6:01 ` [PATCH, rtl-optimization]: Fix PR rtl-optimization/33638 Ian Lance Taylor
2007-10-09 6:38 ` Eric Botcazou
2007-10-09 7:19 ` Ian Lance Taylor
2007-10-09 11:51 ` Kenneth Zadeck
2007-10-09 12:31 ` Uros Bizjak
2007-10-09 15:42 ` Ian Lance Taylor
2007-10-09 15:42 ` Ian Lance Taylor
2007-10-09 16:05 ` Kenneth Zadeck
2007-10-09 17:09 ` Ian Lance Taylor
2007-10-09 19:37 ` Eric Botcazou
2007-10-09 19:55 ` Kenneth Zadeck
2007-10-09 21:55 ` Eric Botcazou
2007-10-10 12:19 ` Eric Botcazou
2007-10-10 19:21 ` Eric Botcazou
2007-10-12 15:49 ` Ian Lance Taylor
2007-10-12 17:10 ` Eric Botcazou
2007-10-14 16:29 ` Eric Botcazou
2007-10-15 5:47 ` Ian Lance Taylor
2007-10-15 7:43 ` Eric Botcazou [this message]
2007-10-10 10:45 ` Eric Botcazou
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