Internal Compiler Error Help

[Saurabh Das via Digitalmars-d-learn]

Hello,

We have been working on a genetic programming project, and 
occasionally the compiler fails and gives an internal error. I've 
captured and reduced one of these down to a single expression. 
See http://dpaste.dzfl.pl/e7a66aa067ab (reduced_expr.d)

When I compile this file using: dmd -c -O reduced_expr.d

It says:
DMD 2.066.1] Internal error: backend/cod1.c 1562
DMD 2.067.1] Internal error: backend/cod1.c 1567

The compile succeeds without the '-O' flag.

Am I correct in assuming that an internal error in the compiler 
should be filed as a bug report?

As you can see, the expression is a massive ugly thing, as is 
often the case with genetic programming. I'd like to reduce this 
expression further before filing said bug report. I recall seeing 
a project on this forum which automatically figures out the 
simplest program which causes a compile failure. Can someone 
kindly point me to it?

Thanks,
Saurabh