Comment 15 for bug 1940029

root@f:~# apt install gcc-10 libc6-dev-i386
...
root@f:~# gcc-10 -Wall -Werror test.c -o test.o
root@f:~# gcc-10 -march=i486 -Wall -Werror test.c -o test.o
cc1: error: CPU you selected does not support x86-64 instruction set
cc1: error: ‘-fcf-protection=full’ is not supported for this target

^^ issue
gcc-10 -v |& tail -n 1
gcc version 10.3.0 (Ubuntu 10.3.0-1ubuntu1~20.04)

Upgrade to 10.5.0-1ubuntu1~20.04 worked fine (but was a bit much output as I move to all in proposed)

root@f:~# gcc-10 -v |& tail -n 1
gcc version 10.5.0 (Ubuntu 10.5.0-1ubuntu1~20.04)
root@f:~# gcc-10 -march=i486 -Wall -Werror test.c -o test.o
cc1: error: CPU you selected does not support x86-64 instruction set
cc1: error: ‘-fcf-protection=full’ is not supported for this target

Hmm, is this bug really fixed.
Sorry I didn't have the time to manually verify any of the before.
But it seems it was released without a verification due to that :-/

Checking latest Jammy as I had it around:

$ gcc-11 -v |& tail -n 1
gcc version 11.3.0 (Ubuntu 11.3.0-1ubuntu1~22.04.1)
$ gcc-11 -march=i486 -Wall -Werror test.c -o test.o
cc1: error: CPU you selected does not support x86-64 instruction set
cc1: error: ‘-fcf-protection=full’ is not supported for this target

$ gcc-12 -v |& tail -n 1
gcc version 12.1.0 (Ubuntu 12.1.0-2ubuntu1~22.04)
$ gcc-12 -march=i486 -Wall -Werror test.c -o test.o
cc1: error: CPU you selected does not support x86-64 instruction set
cc1: error: ‘-fcf-protection=full’ is not supported for this target