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[bugfix] late propagations need to be re-propagated

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Indeed, the previous strategy was that late propagations didn't need to
be propagated since they already have been, however that may not be the
case as a conflict might arise during propagation. It manifested as a
bug when the conflict did *not* depend on local hyps, and was tragically
lost during popping.
This commit is contained in:
Guillaume Bury 2016-11-22 16:43:49 +01:00
parent 0dc44b1173
commit e3d8513286
1 changed files with 9 additions and 8 deletions
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17
src/core/internal.ml
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@ -383,8 +383,9 @@ module Make
else begin
Log.debugf 5 "Backtracking to lvl %d" (fun k -> k lvl);
(* We set the head of the solver and theory queue to what it was. *)
env.elt_head <- Vec.get env.elt_levels lvl;
env.th_head <- env.elt_head;
let head = ref (Vec.get env.elt_levels lvl) in
env.elt_head <- !head;
env.th_head <- !head;
(* Now we need to cleanup the vars that are not valid anymore
(i.e to the right of elt_head in the queue. *)
for c = env.elt_head to Vec.size env.elt_queue - 1 do
@ -394,8 +395,8 @@ module Make
a level lower than [lvl], in which case we just move it back. *)
| Lit l ->
if l.l_level <= lvl then begin
Vec.set env.elt_queue env.elt_head (of_lit l);
env.elt_head <- env.elt_head + 1
Vec.set env.elt_queue !head (of_lit l);
head := !head + 1
end else begin
l.assigned <- None;
l.l_level <- -1;
@ -404,11 +405,11 @@ module Make
(* A variable is not true/false anymore, one of two things can happen: *)
| Atom a ->
if a.var.v_level <= lvl then begin
(* It is a semantic propagation, which can be late, and has a level
(* It is a late propagation, which has a level
lower than where we backtrack, so we just move it to the head
of the queue, to be propagated again. *)
Vec.set env.elt_queue env.elt_head (of_atom a);
env.elt_head <- env.elt_head + 1
Vec.set env.elt_queue !head (of_atom a);
head := !head + 1
end else begin
(* it is a result of bolean propagation, or a semantic propagation
with a level higher than the level to which we backtrack,
@ -423,7 +424,7 @@ module Make
(* Recover the right theory state. *)
Plugin.backtrack (Vec.get env.th_levels lvl);
(* Resize the vectors according to their new size. *)
Vec.shrink env.elt_queue ((Vec.size env.elt_queue) - env.elt_head);
Vec.shrink env.elt_queue ((Vec.size env.elt_queue) - !head);
Vec.shrink env.elt_levels ((Vec.size env.elt_levels) - lvl);
Vec.shrink env.th_levels ((Vec.size env.th_levels) - lvl);
end;