3 files changed, 30 insertions, 10 deletions
diff --git a/src/preprocessing/passes/bv_to_int.cpp b/src/preprocessing/passes/bv_to_int.cpp
index b6f53f8c2..ad2707035 100644
--- a/src/preprocessing/passes/bv_to_int.cpp
+++ b/src/preprocessing/passes/bv_to_int.cpp
@@ -408,6 +408,14 @@ Node BVToInt::translateWithChildren(Node original,
       returnNode = translated_children[0];
       break;
     }
+    case kind::INT_TO_BITVECTOR:
+    {
+      // ((_ int2bv n) t) ---> (mod t 2^n)
+      size_t sz = original.getOperator().getConst<IntToBitVector>().d_size;
+      returnNode = d_nm->mkNode(
+          kind::INTS_MODULUS_TOTAL, translated_children[0], pow2(sz));
+    }
+    break;
     case kind::BITVECTOR_AND:
     {
       // We support three configurations:
diff --git a/src/smt/set_defaults.cpp b/src/smt/set_defaults.cpp
index b9095c91b..31d14c569 100644
--- a/src/smt/set_defaults.cpp
+++ b/src/smt/set_defaults.cpp
@@ -163,15 +163,6 @@ void setDefaults(LogicInfo& logic, bool isInternalSubsolver)
     }
   }
 
-  /* Only BVSolver::LAZY natively supports int2bv and nat2bv, for other solvers
-   * we need to eagerly eliminate the operators. */
-  if (options::bvSolver() == options::BVSolver::SIMPLE
-      || options::bvSolver() == options::BVSolver::BITBLAST)
-  {
-    opts.bv.bvLazyReduceExtf = false;
-    opts.bv.bvLazyRewriteExtf = false;
-  }
-
   /* Disable bit-level propagation by default for the BITBLAST solver. */
   if (options::bvSolver() == options::BVSolver::BITBLAST)
   {
@@ -198,6 +189,8 @@ void setDefaults(LogicInfo& logic, bool isInternalSubsolver)
 
   if (options::solveBVAsInt() != options::SolveBVAsIntMode::OFF)
   {
+    // do not rewrite bv2nat eagerly
+    opts.bv.bvLazyRewriteExtf = true;
     if (options::boolToBitvector() != options::BoolToBVMode::OFF)
     {
       throw OptionException(
@@ -222,6 +215,14 @@ void setDefaults(LogicInfo& logic, bool isInternalSubsolver)
       logic.lock();
     }
   }
+  else if (options::bvSolver() == options::BVSolver::SIMPLE
+           || options::bvSolver() == options::BVSolver::BITBLAST)
+  {
+    // Only BVSolver::LAZY natively supports int2bv and nat2bv, for other
+    // solvers we need to eagerly eliminate the operators. Note this is only
+    // applied if we are not eliminating BV (e.g. with solveBVAsInt).
+    opts.bv.bvLazyReduceExtf = false;
+  }
 
   // set options about ackermannization
   if (options::ackermann() && options::produceModels()
diff --git a/src/theory/bv/theory_bv_rewriter.cpp b/src/theory/bv/theory_bv_rewriter.cpp
index 476803c59..4e1076763 100644
--- a/src/theory/bv/theory_bv_rewriter.cpp
+++ b/src/theory/bv/theory_bv_rewriter.cpp
@@ -64,7 +64,18 @@ TrustNode TheoryBVRewriter::expandDefinition(Node node)
     case kind::BITVECTOR_SDIV:
     case kind::BITVECTOR_SREM:
     case kind::BITVECTOR_SMOD: ret = eliminateBVSDiv(node); break;
-
+    case kind::BITVECTOR_TO_NAT:
+      if (!options::bvLazyReduceExtf())
+      {
+        ret = utils::eliminateBv2Nat(node);
+      }
+      break;
+    case kind::INT_TO_BITVECTOR:
+      if (!options::bvLazyReduceExtf())
+      {
+        ret = utils::eliminateInt2Bv(node);
+      }
+      break;
     default: break;
   }
   if (!ret.isNull() && node != ret)