Re: Improve DOM's ability to derive equivalences when traversing edges

[Jeff Law <law@redhat.com>]

On 08/29/2017 09:42 AM, Christophe Lyon wrote:
> On 29 August 2017 at 17:28, Jeff Law <law@redhat.com> wrote:
>> On 08/29/2017 03:13 AM, Christophe Lyon wrote:
>>> Hi Jeff,
>> [ ... ]
>>>>
>>>> commit a370df2c52074abbb044d1921a0c7df235758050
>>>> Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
>>>> Date:   Tue Aug 29 05:03:36 2017 +0000
>>>>
>>>>             * tree-ssa-dom.c (edge_info::record_simple_equiv): Call
>>>>             derive_equivalences.
>>>>             (derive_equivalences_from_bit_ior, record_temporary_equivalences):
>>>>             Code moved into....
>>>>             (edge_info::derive_equivalences): New private member function
>>>>
>>>>             * gcc.dg/torture/pr57214.c: Fix type of loop counter.
>>>>             * gcc.dg/tree-ssa/ssa-sink-16.c: Disable DOM.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-11.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-12.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-13.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-14.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-15.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-16.c: New test.
>>>>             * gcc.dg/tree-ssa/ssa-dom-thread-17.c: New test.
>>>>
>>>>     git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@251397 138bc75d-0d04-0410-961f-82ee72b054a4
>>>>
>>>
>>> 3 of the new tests fail on arm-none-linux-gnueabihf
>>> --with-cpu=cortex-a15 --with-fpu=vfpv3-d16-fp16
>>>
>>> FAIL:    gcc.dg/tree-ssa/ssa-dom-thread-11.c scan-tree-dump-times dom2
>>> "Threaded" 1
>>> FAIL:    gcc.dg/tree-ssa/ssa-dom-thread-14.c scan-tree-dump-times dom2
>>> "Threaded" 1
>>> FAIL:    gcc.dg/tree-ssa/ssa-dom-thread-16.c scan-tree-dump-times dom2
>>> "Threaded" 1
>>>
>>> they do pass when configuring for cpu cortex-a9/a15 and fpu neon-fp16/neon-vfpv4
>>>
>>> I do not have the dumps since it's automated testing; let me know if
>>> you need me to
>>> reproduce it manually and extract the dumps.
>> Strange.  I can't reproduce this.
>>
>> /home/law/gcc-testing/gcc2/configure --target=arm-none-linux-gnueabihf
>> --with-cpu=cortex-a15 --with-fpu=vfpv3-d16-fp16
>>
> 
> Sorry, it was a typo: I meant cortex-a5.
Ah.  I see it now.

Isn't this really an indicator that the ARM test in
check_effective_target_logical_op_short_circuit is wrong?

AFAICT that test just looks to see if a particular preprocessor symbol
is defined.

WOuldn't it be better to check the output of -mprint-tune-info which
should make the test DTRT in all situations?

jeff