> On 16 Sep 2021, at 18:11, Qing Zhao via Gcc-patches <gcc-patches@gcc.gnu.org>
> wrote:
>
>
>
>> On Sep 16, 2021, at 10:47 AM, Jakub Jelinek <ja...@redhat.com> wrote:
>>
>> On Thu, Sep 16, 2021 at 03:39:46PM +0000, Qing Zhao wrote:
>>>> Even -mtune= is needed if you want to stay safe, otherwise people testing
>>>> with --target_board=unix/-mtune=cascadelake (or whatever else) might get
>>>> failures.
>>>
>>> Okay. Will try this.
>>>>
>>>>>> and ideally also -fno-stack-protector
>>>>>> -fno-stack-clash-protection etc.
>>>>>
>>>>> Could you explain a little bit on this why?
>>>>
>>>> In case people test e.g. with
>>>> --target_board=unix/\{,-fstack-protector-all\}
>>>> etc. (e.g. in Fedora/RHEL we do).
>>>> For the RTL scanning checks if they are done fairly early, those options
>>>> might not change anything, but with the ones scanning in the assembly,
>>>> one needs to watch if those options don't add e.g. in the prologue or
>>>> epilogue further copies of the instructions you scan for.
>>>
>>> I see.
>>>
>>> Thank you.
>>
>> Basically, try to test with a bunch of semi-randomly chosen option sets and
>> see what breaks and what works and then for the cases you think are common
>> enough and worth adjusting testcases adjust them, otherwise add dg-options
>> to make sure the expected arch/tune/etc. are in effect.
>> make check-gcc
>> RUNTESTFLAGS='--target_board=unix\{-m64,-m64/-march=skylake-avx512,-m64/-fstack-protector-all,-m64/-fstack-clash-protection,-m32/-mno-sse,-m32/-mtune=bonnell,-m32/-march=bonnell,-m32/-fstack-protector-all/-fstack-clash-protection\}
>> i386.exp=auto-init*'
>
> Thanks a lot for the suggestions and help, I will try this.
I might suggest adding -fPIC or -fpic to the mix too (if it’s relevant to the
tests) there are quite a few testcases that fail when run on Darwin (or HJ’s
pic tester versions) because of the difference in code-gen.
Iain
>
> Qing
>> etc.
>>
>> Jakub
