Looking at the output of B::Concise, there are two extra opcodes in the block version. Compare:

$ perl -MO=Concise -e 'my $total = 0; $total += $_ for(1..1e6);'

to:

$ perl -MO=Concise -e 'my $total = 0; for(1..1e6){$total += $_;}'

At first glance, it looks like the opcodes manage entering and exiting the block scope.

In reply to Re: Benchmarking for loops? by chromatic
in thread Benchmarking for loops? by Anonymous Monk

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