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| author | Mathias Preiner <mathias.preiner@gmail.com> | 2021-08-25 17:50:53 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-08-26 00:50:53 +0000 |
| commit | a81064b538382670f25c87f138961f12def7880a (patch) | |
| tree | 7a536209012716bbe4c6fb4aa6c651b47494a3d5 | |
| parent | 71f025753f734ddade5da333dfe2d144fbc13221 (diff) | |
int2bv: Fix conversion of signed bit-vector values. (#7061)
This commit fixes the conversion of signed bit-vector values to integers in the int-to-bv preprocessing pass.
| -rw-r--r-- | src/preprocessing/passes/int_to_bv.cpp | 16 | ||||
| -rw-r--r-- | test/regress/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | test/regress/regress0/bv/int_to_bv_model2.smt2 | 6 |
3 files changed, 21 insertions, 2 deletions
diff --git a/src/preprocessing/passes/int_to_bv.cpp b/src/preprocessing/passes/int_to_bv.cpp index 8c18ccf54..41d52d1ae 100644 --- a/src/preprocessing/passes/int_to_bv.cpp +++ b/src/preprocessing/passes/int_to_bv.cpp @@ -217,8 +217,20 @@ Node IntToBV::intToBV(TNode n, NodeMap& cache) result = sm->mkDummySkolem("__intToBV_var", nm->mkBitVectorType(size), "Variable introduced in intToBV pass"); - Node bv2nat = nm->mkNode(kind::BITVECTOR_TO_NAT, result); - d_preprocContext->addSubstitution(current, bv2nat); + /** + * Correctly convert signed/unsigned BV values to Integers as follows + * x < 0 ? -nat(-x) : nat(x) + * where x refers to the bit-vector term `result`. + */ + BitVector bvzero(size, Integer(0)); + Node negResult = nm->mkNode(kind::BITVECTOR_TO_NAT, + nm->mkNode(kind::BITVECTOR_NEG, result)); + Node bv2int = nm->mkNode( + kind::ITE, + nm->mkNode(kind::BITVECTOR_SLT, result, nm->mkConst(bvzero)), + nm->mkNode(kind::UMINUS, negResult), + nm->mkNode(kind::BITVECTOR_TO_NAT, result)); + d_preprocContext->addSubstitution(current, bv2int); } } else if (current.isConst()) diff --git a/test/regress/CMakeLists.txt b/test/regress/CMakeLists.txt index ce047c877..ec6d04c1d 100644 --- a/test/regress/CMakeLists.txt +++ b/test/regress/CMakeLists.txt @@ -420,6 +420,7 @@ set(regress_0_tests regress0/bv/inequality05.smt2 regress0/bv/int_to_bv_err_on_demand_1.smt2 regress0/bv/int_to_bv_model.smt2 + regress0/bv/int_to_bv_model2.smt2 regress0/bv/issue-4075.smt2 regress0/bv/issue-4076.smt2 regress0/bv/issue-4130.smt2 diff --git a/test/regress/regress0/bv/int_to_bv_model2.smt2 b/test/regress/regress0/bv/int_to_bv_model2.smt2 new file mode 100644 index 000000000..d4ad9695f --- /dev/null +++ b/test/regress/regress0/bv/int_to_bv_model2.smt2 @@ -0,0 +1,6 @@ +; COMMAND-LINE: --solve-int-as-bv=5 --check-models +(set-logic QF_NIA) +(set-info :status sat) +(declare-const x Int) +(assert (< x 0)) +(check-sat) |