[Bug tree-optimization/18595] [4.0 Regression] IV-OPTS is O(N^3)

[dberlin at dberlin dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-01-25 00:50 -------
Subject: Re:  [4.0 Regression] IV-OPTS is O(N^3)



On Mon, 25 Jan 2005, rakdver at atrey dot karlin dot mff dot cuni dot cz wrote:

>
> ------- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni dot cz  2005-01-25 00:49 -------
> Subject: Re:  [4.0 Regression] IV-OPTS is O(N^3)
>
>>>>>> Uh, symbolic references are or will be used to do data dependence when
>>>>>> MEM_REF and ARRAY_REF couldn't be generated from the pointers.
>>>>>
>>>>> How?  If the reference is left in symbolic form, it means that you know
>>>>> nothing about its value,
>>>>
>>>> Wrong.
>>>>
>>>> We could know things about it's value, such as ranges. We just don't know
>>>> an exact number.
>>>
>>> OK.  This is work for VRP, not scev.
>>
>> And once we have it, we can talk about removing the symbolic stuff from
>> SCEV :)
>
> Once we use any value range info from SCEV, we can speak about leaving
> symbolic references in SCEV until we have a proper VRP :-)
See autovec branch.




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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18595