From: Jeff Law <law@redhat.com>
To: Jakub Jelinek <jakub@redhat.com>, Richard Biener <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Fix -fcompare-debug issues caused by recent VRP assert expr sorting changes (PR debug/81278)
Date: Tue, 04 Jul 2017 15:07:00 -0000 [thread overview]
Message-ID: <a80c29ec-9ee3-082b-1e94-363ab178e5c6@redhat.com> (raw)
In-Reply-To: <20170704124152.GM2123@tucnak>
On 07/04/2017 06:41 AM, Jakub Jelinek wrote:
> On Tue, Jul 04, 2017 at 02:00:13PM +0200, Richard Biener wrote:
>>> That was intentional. If a->e != NULL, then we know that b->e != NULL,
>>> because we have
>>> else if (a->e != NULL && b->e == NULL)
>>> return -1;
>>> earlier. Similarly, if a->e == NULL, then we know that b-> == NULL, because
>>> we have:
>>> if (a->e == NULL && b->e != NULL)
>>> return 1;
>>> earlier.
>>
>> Ah, ok. Twisty ;) I suppose jump threading will have eliminated
>> the extra test.
>
> In the first case maybe, I doubt it would do that after the
> iterative_hash_expr calls which are likely not pure.
Correct. It'll have to assume that the memory objects changed.
Jeff
prev parent reply other threads:[~2017-07-04 15:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-04 11:32 Jakub Jelinek
2017-07-04 11:46 ` Richard Biener
2017-07-04 11:50 ` Jakub Jelinek
2017-07-04 12:00 ` Richard Biener
2017-07-04 12:42 ` Jakub Jelinek
2017-07-04 14:06 ` Richard Biener
2017-07-04 15:07 ` Jeff Law [this message]
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