Automatic generalized phase abstraction for formal verification

Abstract

Abstract-A standard approach to improving circuit performance is to use an N -phase design style where combinational logic is interspersed freely between level sensitive latches controlled by separate clocks. Unfortunately, the use of an N -phase design style will increase the number of state variables by a factor of N , making formal verification many orders of magnitude harder. Previous approaches to solving this problem restrict the kind of designs that can be handled severely and construct an abstracted netlist with fewer state variables by a syntactic analysis that requires the user to identify clocks. We extend the current state of the art by introducing a phase abstraction algorithm that (1) poses no restrictions on the design style that can be used, that (2) avoids an error prone syntactic analysis, that (3) requires no input from users, and that (4) can be integrated into any model checker without requiring HDL code analysis.

ABC: An Academic Industrial-Strength Verification Tool

“…• Phase abstraction, trying to identify clock-like periodic behaviors and deciding to unfold the design several frames depending on the clocks found and the amount of simplification this may allow [6].…”

Speculative reduction-based scalable redundancy identification

“…For SYNTH3, the application of phase abstraction MOD [21] followed by min-area retiming RET [13] and combinational optimization COM [12] on the speculatively-reduced netlist is able to efficiently solve all miters. For IOC, MOD and COM followed by structural isomorphism detection ISO dramatically simplifies the speculatively-reduced netlist.…”

Deeper Bound in BMC by Combining Constant Propagation and Abstraction

“…This leads to an improved bounded model-checking algorithm, which we call BMC-CP. Similar preprocessing simplifications have been shown to be successful [1,4,14,2,15,19]. Our contribution is showing how inputs of the design with a known cyclic pattern can be used as constrains in preprocessing simplifications of the BMC formula for a CNF SAT solver.…”