Word level predicate abstraction and refinement for verifying RTL Verilog

Model checking techniques applied to large industrial circuits suffer from the state space explosion problem. A major technique to address this problem is abstraction. The most commonly used abstraction technique for hardware verification is localization reduction, which removes latches that are not relevant to the property. However, localization reduction fails to reduce the size of the model if the property actually depends on most of the latches. This paper proposed the use of predicate abstraction for verifying RTL Verilog, a technique successfully used for software verification. The main challenge when using predicate abstraction is the discovery of suitable predicates. The authors proposed the use of weakest preconditions of Verilog statements in order to obtain new predicates during abstraction refinement. This technique has not been applied to circuits before. On benchmarks taken from an industrial microprocessor, safety properties with more than 32,000 latches in the cone of influence were successfully verified. The performance of the technique was compared with a modern model checker that implements localization reduction.