On Mon, Jun 1, 2015 at 6:41 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Tue, May 26, 2015 at 1:13 PM, Bin.Cheng <amker.cheng@gmail.com> wrote:
>> Hi,
>> The first part patch improving how we handle overflow in scev is
>> posted at https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01795.html .
>> Here comes the second part patch.
>>
>> This patch does below improvements:
>>   1) Computes and records control iv for each loop's exit edge.  This
>> provides a way to compute overflow information in loop niter and use
>> it in different customers.  It think it's useful, especially with
>> option -funsafe-loop-optimizers.
>>   2) Improve chrec_convert by adding new interface
>> loop_exits_before_overflow.  It checks if a converted IV overflows
>> wrto its type and loop using overflow information of loop's control
>> iv.  This basically propagates no-overflow information from control iv
>> to ivs converted from control iv.  Moreover, we can further improve
>> the logic by using possible VRP information in the future.
>>
>> With this patch, cases like scev-9.c and scev-10.c in patch can be
>> handled now.  Cases reported in PR48052 can be vectorized too.
>> Opinions?
>
> -ENOPATCH
Here comes the patch.  Sorry for the inconvenience.

Thanks,
bin
>
>> Thanks,
>> bin
>>
>>
>> 2015-05-26  Bin Cheng  <bin.cheng@arm.com>
>>
>>     * cfgloop.h (struct control_iv): New.
>>     (struct loop): New field control_ivs.
>>     * tree-ssa-loop-niter.c : Include "stor-layout.h".
>>     (number_of_iterations_lt): Set no_overflow information.
>>     (number_of_iterations_exit): Init control iv in niter struct.
>>     (record_control_iv): New.
>>     (estimate_numbers_of_iterations_loop): Call record_control_iv.
>>     (loop_exits_before_overflow): New.  Interface factored out of
>>     scev_probably_wraps_p.
>>     (scev_probably_wraps_p): Factor loop niter related code into
>>     loop_exits_before_overflow.
>>     (free_numbers_of_iterations_estimates_loop): Free control ivs.
>>     * tree-ssa-loop-niter.h (free_loop_control_ivs): New.
>>
>> gcc/testsuite/ChangeLog
>> 2015-05-26  Bin Cheng  <bin.cheng@arm.com>
>>
>>     PR tree-optimization/48052
>>     * gcc.dg/tree-ssa/scev-8.c: New.
>>     * gcc.dg/tree-ssa/scev-9.c: New.
>>     * gcc.dg/tree-ssa/scev-10.c: New.
>>     * gcc.dg/vect/pr48052.c: New.