  This paper reports on our experiences with verifying automotive C code by
state-of-the-art open source software model checkers. The embedded C code is
automatically generated from Simulink open-loop controller models. Its diverse
features (decision logic, floating-point and pointer arithmetic, rate limiters
and state-flow systems) and the extensive use of floating-point variables make
verifying the code highly challenging. Our study reveals large discrepancies in
coverage - which is at most only 20% of all requirements --- and tool strength
compared to results from the main annual software verification competition. A
hand-crafted, simple extension of the verifier CBMC with $k$-induction delivers
results on 63% of the requirements while the proprietary BTC EmbeddedValidator
covers 80% and obtains bounded verification results for most of the remaining
requirements.
