Infinite loop in transformExpr()

I've stumbled upon what seems to be a core-dumping infinite recursion
in transformExpr(), on 8.1.6.

Backtrace:

Core was generated by `postgres'.
Program terminated with signal 10, Bus error.
Reading symbols from /usr/lib/libssl.so.3...(no debugging symbols
found)...done.
Loaded symbols for /usr/lib/libssl.so.3
Reading symbols from /lib/libcrypto.so.3...(no debugging symbols
found)...done.
Loaded symbols for /lib/libcrypto.so.3
Reading symbols from /lib/libz.so.2...(no debugging symbols
found)...done.
Loaded symbols for /lib/libz.so.2
Reading symbols from /lib/libreadline.so.5...(no debugging symbols
found)...done.
Loaded symbols for /lib/libreadline.so.5
Reading symbols from /lib/libcrypt.so.2...(no debugging symbols
found)...done.
Loaded symbols for /lib/libcrypt.so.2
Reading symbols from /lib/libm.so.3...(no debugging symbols
found)...done.
Loaded symbols for /lib/libm.so.3
Reading symbols from /lib/libutil.so.4...(no debugging symbols
found)...done.
Loaded symbols for /lib/libutil.so.4
Reading symbols from /lib/libc.so.5...(no debugging symbols
found)...done.
Loaded symbols for /lib/libc.so.5
Reading symbols from /lib/libncurses.so.5...(no debugging symbols
found)...done.
Loaded symbols for /lib/libncurses.so.5
Reading symbols from /usr/local/lib/postgresql/dblink.so...(no
debugging symbols found)...done.
Loaded symbols for /usr/local/lib/postgresql/dblink.so
Reading symbols from /usr/local/lib/libpq.so.4...(no debugging symbols
found)...done.
Loaded symbols for /usr/local/lib/libpq.so.4
Reading symbols from /usr/lib/libpthread.so.1...(no debugging symbols
found)...done.
Loaded symbols for /usr/lib/libpthread.so.1
Reading symbols from /libexec/ld-elf.so.1...(no debugging symbols
found)...done.
Loaded symbols for /libexec/ld-elf.so.1

#0 0x080d5979 in transformExpr ()
#1 0x080d6700 in transformExpr ()
#2 0x080d5bbb in transformExpr ()
[...]
#21669 0x080d6700 in transformExpr ()
#21670 0x080d5bbb in transformExpr ()
#21671 0x080d669e in transformExpr ()
#21672 0x080d5ba5 in transformExpr ()
#21673 0x080d4f10 in transformWhereClause ()
#21674 0x080c13dd in parse_sub_analyze ()
#21675 0x080bf36f in parse_sub_analyze ()
#21676 0x080bf110 in parse_sub_analyze ()
#21677 0x080bf021 in parse_analyze ()
#21678 0x0818d949 in pg_analyze_and_rewrite ()
#21679 0x0818dd76 in pg_plan_queries ()
#21680 0x081908d5 in PostgresMain ()
#21681 0x0816e084 in ClosePostmasterPorts ()
#21682 0x0816d887 in ClosePostmasterPorts ()
#21683 0x0816bbcf in PostmasterMain ()
#21684 0x0816b5ed in PostmasterMain ()
#21685 0x0813376b in main ()

This is postgres 8.1.6 compiled from ports (with
--enable-thread-safety) on FreeBSD/i386 5.3 (gcc version 3.4.2
[FreeBSD] 20040728).

Should I file a bug report?

Thanks!

Fernando.