internal error heapCensus unknown object with +RTS -N -hT
$ ghc -O3 -Wall --make -threaded -rtsopts -fspec-constr-count=50 autotune.hs ... $ ./autotune +RTS -N -hT -RTS ... autotune: internal error: heapCensus, unknown object: -538405951 (GHC version 7.0.3 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
The unknown object number varies between program runs, and I got a segmentation fault too in one test.
I didn't manage to provoke a crash with each of -N or -hT alone, but the combination seems problematic.
I compiled ghc-7.0.3 from source with INTEGER_LIBRARY=integer-simple (so I can use hmpfr); my code uses hmpfr, parallel, ad, Vec, and possibly some other things from hackage too - I can try to make a simple test case at some point, or attach the code as-is if it would be useful.