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Re-enable difference rule using set_sort directly

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Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com>
This commit is contained in:
copilot-swe-agent[bot] 2025-10-14 09:49:19 +00:00
parent 4ad33caf99
commit 8da94d2ca3
3 changed files with 12 additions and 8 deletions
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13
src/ast/rewriter/finite_set_rewriter.cpp
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@ -63,10 +63,15 @@ br_status finite_set_rewriter::mk_intersect(unsigned num_args, expr * const * ar
br_status finite_set_rewriter::mk_difference(expr * arg1, expr * arg2, expr_ref & result) {
// set.difference(x, x) -> set.empty
// Note: This simplification is currently disabled due to issues with mk_empty
// in finite_set_decl_plugin. The mk_empty utility function expects an element_sort
// but the plugin's mk_empty expects a finite_set_sort, causing conflicts.
// TODO: Re-enable once finite_set_decl_plugin is fixed
if (arg1 == arg2) {
// Get the set sort directly from the argument
sort* set_sort = arg1->get_sort();
SASSERT(m_util.is_finite_set(set_sort));
// Call mk_empty with set_sort directly as suggested
result = m_util.mk_empty(set_sort);
return BR_DONE;
}
return BR_FAILED;
}

2
src/ast/rewriter/finite_set_rewriter.h
View file

@ -16,7 +16,7 @@ Sample rewrite rules:
set.subset(x,y) -> set.intersect(x,y) = x
set.union(x, x) -> x
set.intersect(x, x) -> x
set.difference(x, x) -> set.empty (currently disabled due to mk_empty issues)
set.difference(x, x) -> set.empty
Generally this module implements basic algebraic simplification rules for finite sets
where the signature is defined in finite_set_decl_plugin.h.

5
src/test/finite_set_rewriter.cpp
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@ -82,12 +82,11 @@ static void test_difference_same() {
app_ref s1(fsets.mk_range(zero, ten), m);
// Test set.difference(s1, s1) -> empty
// Note: This simplification is currently disabled due to issues with mk_empty
expr_ref result(m);
br_status st = rw.mk_difference(s1, s1, result);
// Currently disabled, so should return BR_FAILED
ENSURE(st == BR_FAILED);
ENSURE(st == BR_DONE);
ENSURE(fsets.is_empty(result));
}
static void test_subset_rewrite() {