Abstract: A technique for performing an analysis of a logic design (that includes a native memory array embodied in a netlist) includes detecting an initial transient behavior in the logic design as embodied in the netlist. The technique also includes determining a duration of the initial transient behavior and gathering reduction information on the logic design based on the initial transient behavior. The netlist is then modified based on the reduction information.

Abstract: A logic synthesis program, method and system for simplifying and/or reducing a logic design receives output from a logic simulator that uses symbolic values for stimulus and contains symbolic values in the logic simulator output. Relationships between the nodes dependent on symbolic values can be used to merge nodes or otherwise simplify the logic design. Behaviors such as oscillators, transient values, identical signals, dependent logical states and chicken-switch determined states that depend on the symbolic values can be detected in the simulation results and the netlist simplified using the results of the detection. The netlist can be simplified by inserting registers to represent nodes that assume a symbolic value or combination based on symbolic values either statically or after an initial transient.

Abstract: A mechanism is provided for simplifying a netlist before computational resources are exceeded. For each of a set of suspected equivalences in a proof graph of a netlist, a determination is made as to whether equivalence holds for at least one of an equivalence or an equivalence class by identifying whether the equivalence or equivalence class is either affecting or non-affecting. Responsive to the equivalence or equivalence class being affecting, a proof dependency is recorded as an edge in a proof graph. For each node in the proof graph, a determination is made as to whether the node has a falsified dependency. Responsive to the node failing to have a falsified dependency, identification is made that all dependencies are satisfied and that the equivalences represented by the node in the proof graph are sequential equivalences. The netlist is then simplified by consuming the sequential equivalences.

Abstract: In a first aspect, a first method of designing a circuit is provided. The first method includes the steps of (1) providing a model of an original circuit design including a latch; (2) providing a model of a modified version of the original circuit design, wherein the modified version of the original circuit design includes a set of latches associated with the latch of the original circuit design and voting logic having inputs coupled to respective outputs of latches in the latch set; and (3) during Boolean equivalency checking (BEC), injecting an error on at most a largest minority of the inputs of the voting logic to test the voting logic function.

Abstract: Mechanisms are provided in a design environment for eliminating, coalescing, or bypassing ports. The design environment comprises one mechanism to eliminate unnecessary ports in arrays using disabled and disconnected pin information. The design environment may comprise another mechanism to combine and reduce the number of array ports using address comparisons. The design environment may comprise another mechanism to combine and reduce the number of array ports using disjoint enable comparisons. The design environment may comprise one mechanism to combine and reduce the number of array ports using “don't care” computations. The design environment may comprise another mechanism to reduce the number of array ports through bypassing write-to-read paths around arrays.

Abstract: A technique for performing an analysis of a logic design includes detecting an initial transient behavior in a logic design embodied in a netlist. A duration of the initial transient behavior is also determined. Reduction information on the logic design is gathered based on the initial transient behavior. The netlist is then modified based on the reduction information.

Abstract: A logic synthesis program, method and system for simplifying and/or reducing a logic design receives output from a logic simulator that uses symbolic values for stimulus and contains symbolic values in the logic simulator output. Relationships between the nodes dependent on symbolic values can be used to merge nodes or otherwise simplify the logic design. Behaviors such as oscillators, transient values, identical signals, dependent logical states and chicken-switch determined states that depend on the symbolic values can be detected in the simulation results and the netlist simplified using the results of the detection. The netlist can be simplified by inserting registers to represent nodes that assume a symbolic value or combination based on symbolic values either statically or after an initial transient.

Abstract: A logic simulation program, method and system for obtaining a set of reachable states for a logic design that can be used to provide input to other algorithms that simplify the netlist describing the logic design or perform other types of processing, provides an efficient, compact behavior when simulating large designs. Rather than simulating using ternary input and state value representations that are restricted to true, false and unknown, the techniques of the present invention use input symbolic values that are retained in the set of reachable states retained as the output. Behaviors such as oscillators, transient values, identical signals, dependent logical states and chicken-switch determined states can be detected in the simulation results and the netlist simplified using the results of the detection.

Abstract: Mechanisms are provided in a design environment for minimizing memory array representations for enhanced synthesis and verification. The design environment comprises one mechanism to compress the width of arrays using disconnected pin information. The design environment comprises another mechanism to simplify the enable conditions of array ports using “don't care” computations. The design environment comprises yet another mechanism to reduce address pins from an array through analysis of limitations of readable addresses.

Abstract: A mechanism is provided for simplifying a netlist before computational resources are exceeded. For each of a set of suspected equivalences in a proof graph of a netlist, a determination is made as to whether equivalence holds for at least one of an equivalence or an equivalence class by identifying whether the equivalence or equivalence class is either affecting or non-affecting. Responsive to the equivalence or equivalence class being affecting, a proof dependency is recorded as an edge in a proof graph. For each node in the proof graph, a determination is made as to whether the node has a falsified dependency. Responsive to the node failing to have a falsified dependency, identification is made that all dependencies are satisfied and that the equivalences represented by the node in the proof graph are sequential equivalences. The netlist is then simplified by consuming the sequential equivalences.

Abstract: A mechanism is provided for efficiently determining Boolean satisfiability (SAT) using lazy constraints. A determination is made as to whether a SAT problem is satisfied without constraints in a list of constraints. Responsive to the SAT problem being satisfied without constraints, a set of variable assignments that are determined in satisfying the SAT problem without constraints are fixed. For each constraint in the list of constraints, a determination is made as to whether the SAT problem with the constraint results in the set of variable assignments remaining constant. Responsive to the SAT problem with the constraint resulting in the set of variable assignments remaining constant, the constraint is added to a list of non-affecting constraints and a satisfied result is returned.

Abstract: A mechanism is provided for efficiently determining Boolean satisfiability (SAT) using lazy constraints. A determination is made as to whether a SAT problem is satisfied without constraints in a list of constraints. Responsive to the SAT problem being satisfied without constraints, a set of variable assignments that arc determined in satisfying the SAT problem without constraints are fixed. For each constraint in the list of constraints, a determination is made as to whether the SAT problem with the constraint results in the set of variable assignments remaining constant. Responsive to the SAT problem with the constraint resulting in the set of variable assignments remaining constant, the constraint is added to a list of non-affecting constraints and a satisfied result is returned.

Abstract: A mechanism is provided for simplifying a netlist before computational resources are exceeded. For each of a set of suspected equivalences in a proof graph of a netlist, a determination is made as to whether equivalence holds for at least one of an equivalence or an equivalence class by identifying whether the equivalence or equivalence class is either affecting or non-affecting. Responsive to the equivalence or equivalence class being affecting, a proof dependency is recorded as an edge in a proof graph. For each node in the proof graph, a determination is made as to whether the node has a falsified dependency. Responsive to the node failing to have a falsified dependency, identification is made that all dependencies are satisfied and that the equivalences represented by the node in the proof graph are sequential equivalences. The netlist is then simplified by consuming the sequential equivalences.

Abstract: Mechanisms are provided in a design environment for array concatenation. The design environment comprises one mechanism to concatenate arrays with enable- and address-compatible ports, thereby reducing the number of arrays in a netlist. The design environment comprises another mechanism to migrate read ports from one array to another based upon compatible enable-, address-, and data-compatible write ports, thereby reducing the number of arrays in a netlist. The design environment comprises yet another mechanism to eliminate unnecessary arrays.

Abstract: Mechanisms are provided for refining an abstraction of a netlist for verification or synthesis of an integrated circuit design. The mechanisms receive an abstracted netlist corresponding to an original netlist of the integrated circuit design. The mechanisms determine elements already present in the abstracted netlist and refine the abstracted netlist by expanding the abstracted netlist to include additional elements that are correlated with the elements already present in the abstracted netlist to thereby generate a refined abstracted netlist. In addition, the mechanisms utilize the refined abstracted netlist to perform at least one of verification or synthesis of the integrated circuit design.

Abstract: A method for performing verification is disclosed. The method includes selecting a set of gates to add to a first localization netlist and forming a refinement netlist. A min-cut is computed with sinks having one or more gates in the refinement netlist and sources comprising one or more inputs of an original netlist and one or more registers registers of the original netlist which are not part of the refinement netlist. A final localized netlist is obtained by adding one or more gates to the refinement netlist to grow the refinement netlist until reaching one or more cut-gates of the min-cut.

Abstract: A mechanism is provided for increasing the scalability of formal verification solutions through enabling the use of input reparameterization on logic models that include memory arrays. A pre-processing mechanism enables the selection of a cut-based design partition which enables optimal reductions though input reparameterization given a netlist with constraints. A post-processing mechanism next prevents input reparameterization from creating topologically inconsistent models in the presence of arrays. Additionally, this technique may be used to rectify inconsistent topologies that may arise when reparameterizing even netlists without arrays, namely false sequential dependencies across initialization constructs. Furthermore, a mechanism is provided to undo the effects of memory array based input reparameterization on verification results.

Abstract: A mechanism is provided for efficient redundancy identification, redundancy removal, and sequential equivalence checking with designs including memory arrays. The mechanism includes an array merging component to optimally merge an array output such that if the address is out-of-bounds or the port is not asserted, the array output is converted to a random output. The mechanism also includes a component for determining the equivalence of enabled array outputs rather than the array outputs directly and creating an enabled array output. The mechanism also includes a component that precludes potentially-redundant array cells from participating in the sequential redundancy removal determination. This component first checks for compatibility of the corresponding arrays, then the corresponding read port enables and addresses, then the corresponding initial values, and finally checking that writes to the corresponding columns yield a compatible set of values.

Abstract: A technique for performing an analysis of a logic design (that includes a native memory array embodied in a netlist) includes detecting an initial transient behavior in the logic design as embodied in the netlist. The technique also includes determining a duration of the initial transient behavior and gathering reduction information on the logic design based on the initial transient behavior. The netlist is then modified based on the reduction information.

Abstract: Mechanisms are provided for refining an abstraction of a netlist for verification or synthesis of an integrated circuit design. The mechanisms receive an abstracted netlist corresponding to an original netlist of the integrated circuit design. The mechanisms determine elements already present in the abstracted netlist and refine the abstracted netlist by expanding the abstracted netlist to include additional elements that are correlated with the elements already present in the abstracted netlist to thereby generate a refined abstracted netlist. In addition, the mechanisms utilize the refined abstracted netlist to perform at least one of verification or synthesis of the integrated circuit design.