If you have a look at memory allocation and the op tree with -MO=Debug then you can see that Perl appears to be allocating space in line with requirements. You can see ops 60 32 40 32 40 124 40 76 bytes appart in physical memory.... Pot luck not overwriting a neighbouring op I would have thought:

C:\>type test.pl
my $greet = "Hello World!\n";
print $greet;

C:\>perl -MO=Debug test.pl
LISTOP (0x1bb3c00)
        op_next         0x0
        op_sibling      0x0
        op_ppaddr       PL_ppaddr[OP_LEAVE]
        op_targ         1
        op_type         178
        op_seq          6616
        op_flags        13
        op_private      64
        op_first        0x1bb3b1c
        op_last         0x1bb3bb8
        op_children     5
OP (0x1bb3b1c)
        op_next         0x1bb3c28
        op_sibling      0x1bb3c28
        op_ppaddr       PL_ppaddr[OP_ENTER]
        op_targ         0
        op_type         177
        op_seq          6607
        op_flags        0
        op_private      0
COP (0x1bb3c28)
        op_next         0x1bb3ccc
        op_sibling      0x1bb3ca4
        op_ppaddr       PL_ppaddr[OP_NEXTSTATE]
        op_targ         0
        op_type         174
        op_seq          6608
        op_flags        1
        op_private      0
        cop_label
        cop_stashpv     main
        cop_file        test.pl
        cop_seq         6608
        cop_arybase     0
        cop_line        1
        cop_warnings    0x0
BINOP (0x1bb3ca4)
        op_next         0x1bb3b5c
        op_sibling      0x1bb3b5c
        op_ppaddr       PL_ppaddr[OP_SASSIGN]
        op_targ         0
        op_type         36
        op_seq          6611
        op_flags        69
        op_private      2
        op_first        0x1bb3ccc
        op_last         0x1bb3d18
SVOP (0x1bb3ccc)
        op_next         0x1bb3d18
        op_sibling      0x1bb3d18
        op_ppaddr       PL_ppaddr[OP_CONST]
        op_targ         3
        op_type         5
        op_seq          6609
        op_flags        2
        op_private      0
        op_sv           0x0
Nullsv
OP (0x1bb3d18)
        op_next         0x1bb3ca4
        op_sibling      0x0
        op_ppaddr       PL_ppaddr[OP_PADSV]
        op_targ         1
        op_type         9
        op_seq          6610
        op_flags        178
        op_private      128
COP (0x1bb3b5c)
        op_next         0x1bb3b98
        op_sibling      0x1bb3bb8
        op_ppaddr       PL_ppaddr[OP_NEXTSTATE]
        op_targ         0
        op_type         174
        op_seq          6612
        op_flags        1
        op_private      0
        cop_label
        cop_stashpv     main
        cop_file        test.pl
        cop_seq         6612
        cop_arybase     0
        cop_line        2
        cop_warnings    0x0
LISTOP (0x1bb3bb8)
        op_next         0x1bb3c00
        op_sibling      0x0
        op_ppaddr       PL_ppaddr[OP_PRINT]
        op_targ         0
        op_type         209
        op_seq          6615
        op_flags        5
        op_private      0
        op_first        0x1bb3b98
        op_last         0x1bb3be0
        op_children     2
OP (0x1bb3b98)
        op_next         0x1bb3be0
        op_sibling      0x1bb3be0
        op_ppaddr       PL_ppaddr[OP_PUSHMARK]
        op_targ         0
        op_type         3
        op_seq          6613
        op_flags        2
        op_private      0
OP (0x1bb3be0)
        op_next         0x1bb3bb8
        op_sibling      0x0
        op_ppaddr       PL_ppaddr[OP_PADSV]
        op_targ         1
        op_type         9
        op_seq          6614
        op_flags        3
        op_private      0
test.pl syntax OK

C:\>perl -MO=Debug test.pl >debug
test.pl syntax OK

C:\>perl -ne "m/op_next\s*(\S+)/ and $h{$1}++;END{print \"$_\n\" for s
+ort{$a<=>$b}map{hex}keys %h}" debug
0
29047644
29047704
29047736
29047776
29047808
29047848
29047972
29048012
29048088

C:\>perl -ne "m/op_next\s*(\S+)/ and $h{$1}++;END{print \"$_\n\" for s
+ort{$a<=>$b}map{hex}keys %h}" debug >memloc

C:\>perl -ne "print $_-$a,$/;$a=$_" memloc
0
29047644
60
32
40
32
40
124
40
76

C:\>
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