$ diff <( perl -MO=Concise -e'($a,$b)=($b,$a)' \
                                      | perl -pe's/0x[\da-f]+/0x/g' ) \
        <( perl -MO=Concise -e'($x,$y)=($b,$a)' \
                                      | perl -pe's/0x[\da-f]+/0x/g' )
-e syntax OK
-e syntax OK
4c4
< 9     <2> aassign[t5] vKS/COMMON ->a
---
> 9     <2> aassign[t5] vKS ->a
14c14
< 7              <#> gvsv[*a] s ->8
---
> 7              <#> gvsv[*x] s ->8
16c16
< 8              <#> gvsv[*b] s ->9
---
> 8              <#> gvsv[*y] s ->9