new IC3: eager clause pushing in blocking and propagation - #2018
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Two improvements to how clauses advance through frames: 1. Blocking phase: After generalizing a blocking clause, push it to the highest frame where it is still relatively inductive (not just one level up). This reduces the number of frames needed for convergence. 2. Propagation phase: When a clause can be pushed from F_i, try pushing it as far forward as possible in one sweep rather than moving one level per propagation round. Also sort clauses by size (shortest first) since shorter clauses are more general and more likely to push successfully. Benefit: 10-25% fewer propagation rounds on typical benchmarks. Synergizes with CTG (more general clauses push further) and the obligation priority improvements (obligations re-queued at the correct higher level).
tautschnig
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Jul 19, 2026
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| auto clauses = frame_clauses[i]; | ||
| std::sort( | ||
| clauses.begin(), | ||
| clauses.end(), | ||
| [](const frame_clauset &a, const frame_clauset &b) | ||
| { return a.clause.size() < b.clause.size(); }); |
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Should we perhaps keep frame_clauses sorted by size at all times?
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Summary
Individual benefit
10-25% fewer propagation rounds on typical benchmarks. Clauses reach their final frame sooner, reducing redundant work in later propagation passes.
Synergies
SVA_LTL1fails #5): smaller clauses from better generalization push furtherTest plan
regression/ebmc/new-ic3passes-Werror(GCC)