From: Jeff Law <law@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>, Alan Modra <amodra@gmail.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
Bernd Schmidt <bschmidt@redhat.com>,
gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] PR69195, Reload confused by invalid reg equivs
Date: Sat, 12 Mar 2016 08:26:00 -0000 [thread overview]
Message-ID: <56E3D2BF.90508@redhat.com> (raw)
In-Reply-To: <20160312075821.GK3017@tucnak.redhat.com>
On 03/12/2016 12:58 AM, Jakub Jelinek wrote:
> On Sat, Mar 12, 2016 at 09:43:50AM +1030, Alan Modra wrote:
>> The underlying problem happens somewhere in tree-ssa-dse.c. So we get
>> an indirect jump to a random location instead of a jump to 0.
>
> Well, the testcase is there just to make sure we don't ICE on it.
> And, changing just DSE can't be a complete solution, because one can use
> uninitialized var from the beginning:
> int
> foo (void)
> {
> int x;
> goto *&x;
> }
>
> Jakub
>
I believe Alan's point is DSE deleted the assignment to x which can't be
right as long as we've left in goto *&x.
The goto *&x should be a use of x and thus should have kept the
assignment live.
Jeff
next prev parent reply other threads:[~2016-03-12 8:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 14:54 [RFC] " Alan Modra
2016-03-04 17:40 ` Bernd Schmidt
2016-03-07 14:47 ` Alan Modra
2016-03-10 9:18 ` [PATCH] " Alan Modra
2016-03-10 9:48 ` Bernd Schmidt
2016-03-11 20:40 ` Andreas Schwab
2016-03-11 22:16 ` Alan Modra
2016-03-11 23:13 ` Alan Modra
2016-03-12 7:58 ` Jakub Jelinek
2016-03-12 8:26 ` Jeff Law [this message]
2016-03-12 9:07 ` Alan Modra
2016-03-12 9:29 ` Jakub Jelinek
2016-03-12 11:10 ` Richard Biener
2016-03-12 17:07 ` Jeff Law
2016-03-14 9:56 ` Richard Biener
2016-03-14 19:00 ` Jeff Law
2016-03-15 2:27 ` Alan Modra
2016-03-15 12:17 ` Bernd Schmidt
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