FS#69879 : [nauty] Illegal instruction when executing `geng`

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FS#69879 - [nauty] Illegal instruction when executing `geng`

Attached to Project: Community Packages
Opened by Artemis (Artemis) - Thursday, 04 March 2021, 09:21 GMT
Last edited by Antonio Rojas (arojas) - Thursday, 04 March 2021, 10:25 GMT

Task Type	Bug Report
Category	Packages
Status	Closed
Assigned To	Antonio Rojas (arojas)
Architecture	x86_64
Severity	Medium
Priority	Normal
Reported Version
Due in Version	Undecided
Due Date	Undecided
Percent Complete
Votes	0
Private	No

Details

Description:
When executing `geng 2` from nauty I get a core dump with `illegal hardware instruction`.
The stack trace is
```
Stack trace of thread 252504:
#0 0x000055b358617e27 n/a (geng + 0x1e27)
#1 0x00007f7548ac0b25 __libc_start_main (libc.so.6 + 0x27b25)
#2 0x000055b3586188de n/a (geng + 0x28de)
```

I have current nauty version 27r1-1.

When building the current version from the nauty website with just `./configure` and `make` I can execute the newly built `./geng 2` just fine without any error. So I guess that this is an error in the Arch build?

The offending assembly instruction seems to be `shlx rdi,rax,rcx` which, according to this website [1], is in the BMI2 feature group which in turn was introduced with Intel Haswell starting in 2013 [2]. As I have an older CPU (Ivy Bridge, 2012) I guess there's the problem.

I suspect that some optimizations were turned on due to it being compiled on a newer CPU?

I attached my `/proc/cpuinfo`, the output of running `./configure` (as `configure.log`) and the generated `config.log` in the hope that it helps and I'm happy to provide further details if needed.

[1] https://www.felixcloutier.com/x86/sarx:shlx:shrx
[2] https://en.wikipedia.org/wiki/Bit_manipulation_instruction_set