Re: [PATCH][ARM] Fix for testcase after r228661

[Ramana Radhakrishnan <ramana dot gcc at googlemail dot com>]

On Tue, Oct 20, 2015 at 5:38 PM, Andre Vieira
<Andre.SimoesDiasVieira@arm.com> wrote:
>
>
> On 20/10/15 17:25, Ramana Radhakrishnan wrote:
>>
>> On Tue, Oct 20, 2015 at 4:52 PM, Andre Vieira
>> <Andre.SimoesDiasVieira@arm.com> wrote:
>>>
>>> Hi,
>>>
>>> This patch addresses PR-67948 by changing the xor-and.c test, initially
>>> written for a simplify-rtx pattern, to make it pass post r228661 (see
>>> https://gcc.gnu.org/ml/gcc-patches/2015-10/msg00676.html). This test no
>>> longer triggered the simplify-rtx pattern it was written for prior to
>>> r228661, though other optimizations did lead to the same assembly the
>>> test
>>> checked for. The optimization added with r228661 matches the pattern used
>>> in
>>> the test and optimizes it to a better and still valid sequence. Being
>>> unable
>>> to easily change the test to trigger the original simplify-rtx pattern, I
>>> chose to change it to pass with the new produced assembly sequence.
>>>
>>> This is correct because the transformation is valid and it yields a more
>>> efficient pattern. However, as I pointed out before this test doesn't
>>> test
>>> the optimization it originally was intended for.
>>>
>>> Tested by running regression tests for armv6.
>>>
>>> Is this OK to commit?
>>>
>>
>> Missing Changelog - please remember to put the PR number in the
>> Changelog in the correct format i.e PR testsuite/67948. Ok with that.
>>
>> I suspect that the simplify-rtx.c is much less likely to trigger given
>> your match.pd change, but it will be fun proving that.
>
> Ideally, I'd like to prove the simplify-rtx.c couldn't be triggered anymore.
> Though I wouldn't know where to begin with that. I did spend a tiny effort
> trying to trigger it with a version before the match.pd change, but with no
> success.

>>
>>
>> regards
>> ramana
>>
>>
>>> Thanks,
>>> Andre
>>
>>
> Here is the ChangeLog (with the PR), sorry for that!
>
> gcc/testsuite/ChangeLog
> 2015-10-15  Andre Vieira  <andre.simoesdiasvieira@arm.com>
>
>         PR testsuite/67948
>         * gcc.target/arm/xor-and.c: check for eor instead of orr.

Applied with a minor tweak to the changelog message.

regards
Ramana