Re: Ping: Re: [PATCH 1/2] gcc: Remove unneeded global flag.

[Jeff Law <law@redhat.com>]

On 11/29/2016 07:02 AM, Andrew Burgess wrote:
> * Jeff Law <law@redhat.com> [2016-11-28 15:08:46 -0700]:
>
>> On 11/24/2016 02:40 PM, Andrew Burgess wrote:
>>> * Christophe Lyon <christophe.lyon@linaro.org> [2016-11-21 13:47:09 +0100]:
>>>
>>>> On 20 November 2016 at 18:27, Mike Stump <mikestump@comcast.net> wrote:
>>>>> On Nov 19, 2016, at 1:59 PM, Andrew Burgess <andrew.burgess@embecosm.com> wrote:
>>>>>>> So, your new test fails on arm* targets:
>>>>>>
>>>>>> After a little digging I think the problem might be that
>>>>>> -freorder-blocks-and-partition is not supported on arm.
>>>>>>
>>>>>> This should be detected as the new tests include:
>>>>>>
>>>>>>    /* { dg-require-effective-target freorder } */
>>>>>>
>>>>>> however this test passed on arm as -freorder-blocks-and-partition does
>>>>>> not issue any warning unless -fprofile-use is also passed.
>>>>>>
>>>>>> The patch below extends check_effective_target_freorder to check using
>>>>>> -fprofile-use.  With this change in place the tests are skipped on
>>>>>> arm.
>>>>>
>>>>>> All feedback welcome,
>>>>>
>>>>> Seems reasonable, unless a -freorder-blocks-and-partition/-fprofile-use person thinks this is the wrong solution.
>>>>>
>>>>
>>>> Hi,
>>>>
>>>> As promised, I tested this patch: it makes
>>>> gcc.dg/tree-prof/section-attr-[123].c
>>>> unsupported on arm*, and thus they are not failing anymore :-)
>>>>
>>>> However, it also makes other tests unsupported, while they used to pass:
>>>>
>>>>   gcc.dg/pr33648.c
>>>>   gcc.dg/pr46685.c
>>>>   gcc.dg/tree-prof/20041218-1.c
>>>>   gcc.dg/tree-prof/bb-reorg.c
>>>>   gcc.dg/tree-prof/cold_partition_label.c
>>>>   gcc.dg/tree-prof/comp-goto-1.c
>>>>   gcc.dg/tree-prof/pr34999.c
>>>>   gcc.dg/tree-prof/pr45354.c
>>>>   gcc.dg/tree-prof/pr50907.c
>>>>   gcc.dg/tree-prof/pr52027.c
>>>>   gcc.dg/tree-prof/va-arg-pack-1.c
>>>>
>>>> and failures are now unsupported:
>>>>   gcc.dg/tree-prof/cold_partition_label.c
>>>>   gcc.dg/tree-prof/section-attr-1.c
>>>>   gcc.dg/tree-prof/section-attr-2.c
>>>>   gcc.dg/tree-prof/section-attr-3.c
>>>>
>>>> So, maybe this patch is too strong?
>>>
>>> In all of the cases that used to pass the tests are compile only tests
>>> (except for cold_partition_label, which I discuss below).
>>>
>>> On ARM passing -fprofile-use and -freorder-blocks-and-partition
>>> results in a warning, and the -freorder-blocks-and-partition flag is
>>> ignored.  However, disabling -freorder-blocks-and-partition doesn't
>>> stop any of the tests compiling, hence the passes.
>>>
>>> All the tests include:
>>>
>>>   /* { dg-require-effective-target freorder } */
>>>
>>> which I understand to mean, the tests requires the 'freorder' feature
>>> to be supported (which corresponds to -freorder-blocks-and-partition).
>>>
>>> For cold_partition_label and my new tests it's seems clear that the
>>> lack of support for -freorder-blocks-and-partition on ARM is the cause
>>> of the test failures.
>>>
>>> So, is it reasonable to give up the other tests as "unsupported"?  I'd
>>> be inclined to say yes, but I happy to rework the patch if anyone has
>>> a suggestion for an alternative approach.
>> It is reasonable.  It's not uncommon to have to drop various tests to
>> UNSUPPORTED, particularly things which depend on assembler/linker
>> capabilities, the target runtime system, etc.
>
> OK, I'm going to take that as approval for my patch[1].  I'll wait a
> couple of days to give people a chance to correct me, then I'll push
> the change.  This should resolve the test regressions I introduced for
> ARM.
I'll just go ahead and explicitly ACK this.

Thanks,
jeff