From: Qing Zhao <qing.zhao@oracle.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: gcc@gcc.gnu.org, Jeff Law <law@redhat.com>,
gcc Patches <gcc-patches@gcc.gnu.org>
Subject: Re: A bug in vrp_meet?
Date: Fri, 01 Mar 2019 21:02:00 -0000 [thread overview]
Message-ID: <ADBDF027-E33E-4CC1-AEDA-476B96C28337@oracle.com> (raw)
In-Reply-To: <E18B0E1D-000F-4104-A2B5-EE8C2BB31516@gmail.com>
> On Mar 1, 2019, at 1:25 PM, Richard Biener <richard.guenther@gmail.com> wrote:
>
> On March 1, 2019 6:49:20 PM GMT+01:00, Qing Zhao <qing.zhao@oracle.com <mailto:qing.zhao@oracle.com>> wrote:
>> Jeff,
>>
>> thanks a lot for the reply.
>>
>> this is really helpful.
>>
>> I double checked the dumped intermediate file for pass “dom3", and
>> located the following for _152:
>>
>> ****BEFORE the pass “dom3”, there is no _152, the corresponding Block
>> looks like:
>>
>> <bb 4> [local count: 12992277]:
>> _98 = (int) ufcMSR_52(D);
>> k_105 = (sword) ufcMSR_52(D);
>> i_49 = _98 > 0 ? k_105 : 0;
>>
>> ***During the pass “doms”, _152 is generated as following:
>>
>> Optimizing block #4
>> ….
>> Visiting statement:
>> i_49 = _98 > 0 ? k_105 : 0;
>> Meeting
>> [0, 65535]
>> and
>> [0, 0]
>> to
>> [0, 65535]
>> Intersecting
>> [0, 65535]
>> and
>> [0, 65535]
>> to
>> [0, 65535]
>> Optimizing statement i_49 = _98 > 0 ? k_105 : 0;
>> Replaced 'k_105' with variable '_98'
>> gimple_simplified to _152 = MAX_EXPR <_98, 0>;
>> i_49 = _152;
>> Folded to: i_49 = _152;
>> LKUP STMT i_49 = _152
>> ==== ASGN i_49 = _152
>>
>> then bb 4 becomes:
>>
>> <bb 4> [local count: 12992277]:
>> _98 = (int) ufcMSR_52(D);
>> k_105 = _98;
>> _152 = MAX_EXPR <_98, 0>;
>> i_49 = _152;
>>
>> and all the i_49 are replaced with _152.
>>
>> However, the value range info for _152 doesnot reflect the one for
>> i_49, it keeps as UNDEFINED.
>>
>> is this the root problem?
>
> It looks like DOM fails to visit stmts generated by simplification. Can you open a bug report with a testcase?
The problem is, It took me quite some time in order to come up with a small and independent testcase for this problem,
a little bit change made the error disappear.
do you have any suggestion on this? or can you give me some hint on how to fix this in DOM? then I can try the fix on my side?
Thanks a lot.
Qing
>
> Richard.
>
next prev parent reply other threads:[~2019-03-01 21:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 17:05 Qing Zhao
2019-02-28 19:54 ` Jeff Law
2019-03-01 17:49 ` Qing Zhao
2019-03-01 19:25 ` Richard Biener
2019-03-01 21:02 ` Qing Zhao [this message]
2019-03-04 11:45 ` Richard Biener
2019-03-04 16:09 ` Qing Zhao
2019-03-04 22:01 ` Qing Zhao
2019-03-05 9:48 ` Richard Biener
2019-03-05 10:44 ` Richard Biener
2019-03-05 14:45 ` Richard Biener
2019-03-05 21:36 ` Jeff Law
2019-03-06 10:06 ` Richard Biener
2019-03-07 12:47 ` Richard Biener
2019-05-05 21:09 ` Eric Botcazou
2019-05-06 11:27 ` Richard Biener
2019-03-19 19:53 ` Jeff Law
2019-03-20 8:27 ` Richard Biener
2019-03-05 21:27 ` Jeff Law
2019-03-05 21:17 ` Jeff Law
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