[cfe-dev] Fwd: Optimization flags causing segfault on clang

[Craig Topper via cfe-dev]

That's not supposed to happen. What was the failure?

On Fri, Jul 7, 2017 at 1:01 AM ROHIT KUMAR <rohitpoddar92 at gmail.com> wrote:

> Yes. With this flag, I got compilation failure.
>
> On Jul 7, 2017 1:28 PM, "Craig Topper" <craig.topper at gmail.com> wrote:
>
>> You got a compilation failure not a runtime failure?
>>
>> On Fri, Jul 7, 2017 at 12:19 AM ROHIT KUMAR <rohitpoddar92 at gmail.com>
>> wrote:
>>
>>> Thanks, Craig.
>>>
>>> So with this argument, the build failed on compilation with the last log
>>> as
>>>
>>> *"BISECT: NOT running pass (60626) optimize barriers pass on function
>>> ... "*
>>>
>>> It points to a function in a class where we also had a high suspicion
>>> for. So it makes sense.
>>>
>>> So it is very likely that the way our code is written is not meeting the
>>> standards used by clang and one or other optimization is breaking it.
>>>
>>> Do you have any idea which flag is doing this "optimize barriers pass on
>>> function" which we can ignore?
>>>
>>>
>>> On Fri, Jul 7, 2017 at 11:55 AM, Craig Topper <craig.topper at gmail.com>
>>> wrote:
>>>
>>>> You can use -mllvm -opt-bisect-limit=<limit> to bisect where the error
>>>> occurs. More documentation here http://llvm.org/docs/OptBisect.html
>>>>
>>>> ~Craig
>>>>
>>>> On Thu, Jul 6, 2017 at 11:18 PM, ROHIT KUMAR via cfe-dev <
>>>> cfe-dev at lists.llvm.org> wrote:
>>>>
>>>>> Hey,
>>>>>
>>>>> Context: Android native code built with clang using Android Studio.
>>>>>
>>>>> We have been using GCC(Eclipse) for quite a while, now we are trying
>>>>> to move our huge code base to clang (to AndroidStudio).
>>>>>
>>>>> With GCC we were using -O3 optimization and everything was working
>>>>> fine, but with clang, even -O1 is causing Android apps to crash on runtime
>>>>> with the seg fault.
>>>>>
>>>>> Since apps are working fine when compiled with -O0, so my guess is
>>>>> some kind of optimization is not supported for our code base which is/are
>>>>> introduced by O1/2/3 flags.
>>>>>
>>>>> Is there a way I can disable the flags introduced by -O1 one-by-one to
>>>>> figure out the culprit flag(s)?
>>>>>
>>>>> Can anyone suggest me such flags to disable optimizations one-by-one?
>>>>> I tried googling but could not find much help.
>>>>>
>>>>> I am stuck on this issue for quite a while now. I would really
>>>>> appreciate the help. I am looking for a more general advice on flags to
>>>>> disable optimizations one-by-one with -O1, because making changes in the
>>>>> code base would not be possible.
>>>>>
>>>>> Thanks.
>>>>> Rohit Kumar
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> cfe-dev mailing list
>>>>> cfe-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>>>
>>>>>
>>>>
>>> --
>> ~Craig
>>
> --
~Craig
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