Even more illegal instruction stuff

[John Klos <john%ziaspace.com@localhost>]

2010/07/25 08:11:20  1103/9089=12.1% devel/autoconf @ vax> 
autom4te_perllibdir='..'/lib                                  AUTOM4TE_CFG='../lib/autom4te.cfg'    ../bin/autom4te      -B '..'/lib -B '..'/lib --language M4sh --cache '' --melt ./autoconf.as -o autoconf.in
2010/07/25 08:11:20  1103/9089=12.1% devel/autoconf @ vax> [1]   Illegal 
instruction (core dumped) autom4te_perllib...
2010/07/25 08:11:20  1103/9089=12.1% devel/autoconf @ vax> *** Error code 132


My other VAXstation 4000/60, which is in the midst of a bulk package 
build, failed on devel/autoconf and is now working its way through the 
thousands of packages which depend on devel/autoconf. The illegal 
instruction was in perl:

x/i $pc
0x7f506772 <boot_POSIX+4000>:   cvtfd $0x[invalid f-float],-(sp)

How would one go about figuring out what code in perl executed this?

Thanks,
John