what is the difference with and without crc extension support

[Martin Liška]

On 3/3/22 14:52, Dongjiu Geng wrote:
> Thanks for the answer, my source file is complex，it is not convenient
> attach,  because it is company code.

I see. So then you can try -fdump-tree-optimized and compare the corresponding dump file.
Or you can use -fdump-tree-all -fdump-rtl-all and do the same.

> According to your  experience，
> what is the reason about it?

Dunno.

Cheers,
Martin

> 
> Martin Liška <mliska@suse.cz> 于2022年3月3日周四 21:48写道：
>>
>> On 3/3/22 14:41, Dongjiu Geng via Gcc wrote:
>>> Hi,
>>>        My program does not use CRC instructions，but I find the compiled
>>> binary has much difference between using "-march=armv8-a+crc" and
>>> using "-march=armv8-a". Even stranger, when I use
>>> "-march=armv8-a+crc", I find my compiled binary can not run. but when
>>> I change -O2 to -O0 based on "-march=armv8-a+crc",  it can run. I  do
>>> not  know what is the reason.. can you answer it? Thanks.
>>
>> Hello.
>>
>> Please report bug here:
>> https://gcc.gnu.org/bugzilla/
>>
>> and attach a pre-processed source file:
>> https://gcc.gnu.org/bugs/
>>
>> Martin