Re: beta gfortran 14.x.y (using -march=native and intrinsic repeat) gives a signal SIGILL

[Jerry D <jvdelisle2@gmail.com>]

On 8/12/23 6:41 AM, Jorge D'Elia wrote:
> Hi Paul,
> 
> ----- Mensaje original -----
>> De: "Paul Richard Thomas" <paul.richard.thomas@gmail.com>
>> Para: "Jerry" <jvdelisle2@gmail.com>
>> CC: "Jorge D'Elia" <jdelia@cimec.unl.edu.ar>, "Gfortran List" <fortran@gcc.gnu.org>, "Jorge D'Elia"
>> <jdelia@intec.unl.edu.ar>
>> Enviado: Sábado, 12 de Agosto 2023 3:56:44
>> Asunto: Re: beta gfortran 14.x.y (using -march=native and intrinsic repeat) gives a signal SIGILL
>>
>> Hi Jorge,
>>
>>> There were some recent patches in this area IIRC.
>>>
>>> Jerry
>>
>> The tree dump is identical to mine, obtained with GNU Fortran (GCC)
>> 14.0.0 20230809 (experimental), so I doubt that any recent patches are
>> responsible.
> 
> It seems so. Furthermore, I have the feeling that the problem is outside
> GFortran, between the use of -mtune=native versus -march=native. For example,
> 
> $ gfortran --version
> GNU Fortran (GCC) 14.0.0 20230808 (experimental)
> 
> $ ls -all
> total 4
> drwxr-xr-x. 1 jdelia jdelia   16 Aug 12 10:06 .
> drwxr-xr-x. 1 jdelia jdelia 2782 Aug 12 10:05 ..
> -rwxr-xr-x. 1 jdelia jdelia  223 Aug 11 08:28 test.f90
> 
> $ gfortran -mtune=native -fcheck=all -std=f2018 -Wall -Werror -Wextra -g -fdump-tree-original -o test-mtune.exe test.f90
> $ ls -all
> total 36
> drwxr-xr-x. 1 jdelia jdelia   110 Aug 12 10:17 .
> drwxr-xr-x. 1 jdelia jdelia  2782 Aug 12 10:05 ..
> -rwxr-xr-x. 1 jdelia jdelia   223 Aug 11 08:28 test.f90
> -rwxr-xr-x. 1 jdelia jdelia 26856 Aug 12 10:17 test-mtune.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:17 test-mtune-test.f90.005t.original
> 
> $ mv test-mtune-test.f90.005t.original test-mtune.f90.005t.original
> 
> $ ls -all
> total 36
> drwxr-xr-x. 1 jdelia jdelia   100 Aug 12 10:19 .
> drwxr-xr-x. 1 jdelia jdelia  2782 Aug 12 10:05 ..
> -rwxr-xr-x. 1 jdelia jdelia   223 Aug 11 08:28 test.f90
> -rwxr-xr-x. 1 jdelia jdelia 26856 Aug 12 10:17 test-mtune.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:17 test-mtune.f90.005t.original
> 
> $ gfortran -march=native -fcheck=all -std=f2018 -Wall -Werror -Wextra -g -fdump-tree-original -o test-march.exe test.f90
> $ ls -all
> total 68
> drwxr-xr-x. 1 jdelia jdelia   194 Aug 12 10:19 .
> drwxr-xr-x. 1 jdelia jdelia  2782 Aug 12 10:05 ..
> -rwxr-xr-x. 1 jdelia jdelia   223 Aug 11 08:28 test.f90
> -rwxr-xr-x. 1 jdelia jdelia 28064 Aug 12 10:19 test-march.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:19 test-march-test.f90.005t.original
> -rwxr-xr-x. 1 jdelia jdelia 26856 Aug 12 10:17 test-mtune.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:17 test-mtune.f90.005t.original
> 
> $ mv test-march-test.f90.005t.original test-march.f90.005t.original
> 
> $ ls -all
> total 68
> drwxr-xr-x. 1 jdelia jdelia   184 Aug 12 10:19 .
> drwxr-xr-x. 1 jdelia jdelia  2782 Aug 12 10:05 ..
> -rwxr-xr-x. 1 jdelia jdelia   223 Aug 11 08:28 test.f90
> -rwxr-xr-x. 1 jdelia jdelia 28064 Aug 12 10:19 test-march.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:19 test-march.f90.005t.original
> -rwxr-xr-x. 1 jdelia jdelia 26856 Aug 12 10:17 test-mtune.exe
> -rw-r--r--. 1 jdelia jdelia  1405 Aug 12 10:17 test-mtune.f90.005t.original
> 
> $ diff test-mtune.f90.005t.original test-march.f90.005t.original
> # (nothing is shown, thus both tree dumps ares identical).
> 
> $ test-mtune.exe
>    cc :
> 
> $ test-march.exe
> 
> Program received signal SIGILL: Illegal instruction.
> 
> Backtrace for this error:
> #0  0x15268845fb1f in ???
> #1  0x4011c2 in test
> 	at /home/jdelia/TEST/test.f90:6
> #2  0x4012ae in main
> 	at /home/jdelia/TEST/test.f90:8
> Illegal instruction (core dumped)
> 
>> Being unable to reproduce the error, there is not much that I can do.
>> Sorry
> 
> Non problem. To avoid this error, for now we exclude the use
> of -march=native in our makefiles, and just use -mtune=native.
> 
>> Paul
> 
> Thanks for your time.
> 
> Regards.
> Jorge.
> --

I have not been able to reproduce it here.  I tried on:

gcc version 14.0.0 20230804 (experimental) (GCC)

and

gcc version 14.0.0 20230812 (experimental) (GCC)

I wonder if you caught a version in between changes happening?

$ lscpu
Architecture:            x86_64
   CPU op-mode(s):        32-bit, 64-bit
   Address sizes:         48 bits physical, 48 bits virtual
   Byte Order:            Little Endian

I started to draft a PR this morning, not sure.

I know it is a pain to do, can you build a later version of gfortran and 
see if your results are different?

Also, I have seen times where the libgfortran files were out of sync 
with the build because LD_LIBRARY_PATH was not pointing in the correct 
place.  So check these things.

Regards,

Jerry