40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
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#include "internal.h"
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#include "gates.h"
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#include "logging.h"
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bool
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kissat_find_equivalence_gate (kissat * solver, unsigned lit)
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{
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if (!GET_OPTION (equivalences))
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return false;
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if (!kissat_mark_binaries (solver, lit))
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return false;
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value *marks = solver->marks;
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unsigned not_lit = NOT (lit);
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watches *watches = &WATCHES (not_lit);
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unsigned replace = INVALID_LIT;
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for (all_binary_large_watches (watch, *watches))
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{
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if (!watch.type.binary)
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continue;
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const unsigned other = watch.binary.lit;
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const unsigned not_other = NOT (other);
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if (!marks[not_other])
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continue;
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replace = other;
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break;
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}
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kissat_unmark_binaries (solver, lit);
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if (replace == INVALID_LIT)
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return false;
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LOG ("found equivalence gate %s = %s", LOGLIT (lit), LOGLIT (replace));
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const watch watch1 = kissat_binary_watch (replace, false, false);
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PUSH_STACK (solver->gates[1], watch1);
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const watch watch0 = kissat_binary_watch (NOT (replace), false, false);
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PUSH_STACK (solver->gates[0], watch0);
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solver->gate_eliminated = GATE_ELIMINATED (equivalences);
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return true;
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}
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