$ perl -MO=Concise,-exec -e'f() unless $x'
1  <0> enter
2  <;> nextstate(main 1 -e:1) v:{
3  <#> gvsv[*x] s
4  <|> or(other->5) vK/1
5      <0> pushmark s
6      <#> gv[*f] s/EARLYCV
7      <1> entersub[t3] vKS/TARG,1
8  <@> leave[1 ref] vKP/REFC
-e syntax OK

$ perl -MO=Concise,-exec -e'$x or f()'
1  <0> enter
2  <;> nextstate(main 1 -e:1) v:{
3  <#> gvsv[*x] s
4  <|> or(other->5) vK/1
5      <0> pushmark s
6      <#> gv[*f] s/EARLYCV
7      <1> entersub[t4] vKS/TARG,1
8  <@> leave[1 ref] vKP/REFC
-e syntax OK