They are synonyms, and you can find that out with B::Deparse: 
$ perl -MO=Deparse -e 'foreach (1..2) { }'
foreach $_ (1 .. 2) {
    ();
}
-e syntax OK
$ perl -MO=Deparse -e 'for (1..2) { }'
foreach $_ (1 .. 2) {
    ();
}
-e syntax OK

[download]

So they produce the same optree

In reply to Re: For vs. Foreach by moritz
in thread For vs. Foreach by mattford63

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