help with bugpointing an invalid code generation

I normally use bugpoint to debug code gen crashes. I am having a
harder time using it to reduce an invalid code generation.

The code I want to reduce is the testcase of

llvm.org/PR4734

With some help from nick the best so far is

bugpoint -loop-rotate --append-exit-code --llc-safe opt1.bc -Xlinker -lstdc++

bugpoint will acknowledge that there is a problem, but instead of
doing a regular reduce as it would with a crash
it tries to split the file and fails to reduce the test that way.

Is there a way to force it to use the same reduction algorithm used
when reducing a crash?

Thanks,