$n=4; 
print $n." -- ".(--$n||'no more'),".\n" while $n;

# output on perl 5.26 5.24 and before
4 -- 3.
3 -- 2.
2 -- 1.
1 -- no more.

# output on perl 5.28
3 -- 3.
2 -- 2.
1 -- 1.
0 -- no more.


##</code><code>##

$n=4; print $n." -- ",(--$n||'no more'),".\n" while $n;
                    #^--- is a comma now!

# output on perl 5.28
4 -- 3.
3 -- 2.
2 -- 1.
1 -- no more.


##</code><code>##

use B::Concise; 
sub sample { $n=4; print $n." -- ".(--$n||'no more'),".\n" while $n; } 
B::Concise::compile('-exec', "sample", \&sample)->();

__DATA__

# output in perl 5.24

main::sample:
1  <;> nextstate(main -12 99bottles.pl:2) v:{
2  <$> const[IV 4] s
3  <#> gvsv[*n] s
4  <2> sassign vKS/2
5  <;> nextstate(main -12 99bottles.pl:2) v:{
6  <0> enter
7  <#> gvsv[*n] s
8  <|> and(other->9) K/1
9      <0> pushmark s
a      <#> gvsv[*n] s
b      <$> const[PV " -- "] s
c      <2> concat[t3] sK/2
d      <#> gvsv[*n] s
e      <1> predec sK/1
f      <|> or(other->g) sK/1
g          <$> const[PV "no more"] s
h      <2> concat[t5] sKS/2
i      <$> const[PV ".\n"] s
j      <@> print sK
k      <0> unstack s
           goto 7
l  <@> leave K*
m  <1> leavesub[1 ref] K/REFC,1
B::Concise::compile(CODE(0x5ef428))
1  <;> nextstate(main -12 99bottles.pl:2) v:{
2  <$> const[IV 4] s
3  <#> gvsv[*n] s
4  <2> sassign vKS/2
5  <;> nextstate(main -12 99bottles.pl:2) v:{
6  <0> enter
7  <#> gvsv[*n] s
8  <|> and(other->9) K/1
9      <0> pushmark s
a      <#> gvsv[*n] s
b      <$> const[PV " -- "] s
c      <2> concat[t3] sK/2
d      <#> gvsv[*n] s
e      <1> predec sK/1
f      <|> or(other->g) sK/1
g          <$> const[PV "no more"] s
h      <2> concat[t5] sKS/2
i      <$> const[PV ".\n"] s
j      <@> print sK
k      <0> unstack s
           goto 7
l  <@> leave K*
m  <1> leavesub[1 ref] K/REFC,1


# output in 5.28

main::sample:
1  <;> nextstate(main -8 99bottles.pl:2) v:{
2  <$> const[IV 4] s
3  <#> gvsv[*n] s
4  <2> sassign vKS/2
5  <;> nextstate(main -8 99bottles.pl:2) v:{
6  <0> enter
7  <#> gvsv[*n] s
8  <|> and(other->9) K/1
9      <0> pushmark s
a      <#> gvsv[*n] s
b      <#> gvsv[*n] s
c      <1> predec sK/1
d      <|> or(other->e) sK/1
e          <$> const[PV "no more"] s
f      <+> multiconcat(" -- ",-1,4,-1)[t5] sK
g      <$> const[PV ".\n"] s
h      <@> print sK
i      <0> unstack s
           goto 7
j  <@> leave K*
k  <1> leavesub[1 ref] K/REFC,1
B::Concise::compile(CODE(0x4fe6e0))
1  <;> nextstate(main -8 99bottles.pl:2) v:{
2  <$> const[IV 4] s
3  <#> gvsv[*n] s
4  <2> sassign vKS/2
5  <;> nextstate(main -8 99bottles.pl:2) v:{
6  <0> enter
7  <#> gvsv[*n] s
8  <|> and(other->9) K/1
9      <0> pushmark s
a      <#> gvsv[*n] s
b      <#> gvsv[*n] s
c      <1> predec sK/1
d      <|> or(other->e) sK/1
e          <$> const[PV "no more"] s
f      <+> multiconcat(" -- ",-1,4,-1)[t5] sK
g      <$> const[PV ".\n"] s
h      <@> print sK
i      <0> unstack s
           goto 7
j  <@> leave K*
k  <1> leavesub[1 ref] K/REFC,1