Description of problem:

The problem is perhaps best described by showing examples (see below) but given certain input, perl.req gets really, really slow. This came up when I went to upgrade the `cloc` package and `rpmbuild` seemingly got stuck and never finished. I dug into it a tiny bit and got a smaller reproducer (again, see below).

When I add letters to the variable name here perl.req gets *really* slow:

$ cat asdf
sub demo {
  ++$foo if  /\s*<<'/;
}


$ time /usr/lib/rpm/perl.req asdf
real	0m0.361s
user	0m0.358s
sys	0m0.003s

--------------------------------------------------------------

$ cat asdf
sub demo {
  ++$foobar if  /\s*<<'/;
}


$ time /usr/lib/rpm/perl.req asdf
real	0m2.891s
user	0m2.884s
sys	0m0.003s

--------------------------------------------------------------

$ cat asdf
sub demo {
  ++$foobarbaz if  /\s*<<'/;
}


$ time /usr/lib/rpm/perl.req asdf
real	0m23.902s
user	0m23.835s
sys	0m0.019s


Version-Release number of selected component (if applicable):
perl-generators-1.06-1.fc22.noarch

How reproducible:
I haven't tested on newer Fedora. I'm planning on upgrading to F23 or F24 this week, will be able to report then.


Steps to Reproduce:
1. Copypaste the above examples into a file
2. Run `/usr/lib/rpm/perl.req the_file`
3. ???
4. Profit

Actual results:
perl.req becomes very slow


Expected results:
perl.req doesn't become very slow. ;)

Additional info:
Happy to provide any other information, just let me know what you need.