C2 sometimes generates instructions that compute values that go unused, e.g. JDK-8020282. For the ideal graph, we have verification passes to ensure the graph is well-formed. Applying this principle to the generated assembly, we can set out to find such instructions automatically.

A few possibilities to strive towards that:
 - Apply heuristics that detect when the result of an instruction is immediately overwritten by another instruction without reading from it.
 - Leverage the information we have in the hotspot (dis)assembler to perform basic symbolic execution to mark unused computations.