Correctly unshare variables for div and mod constraints. Fixes #170.

Gecode · Aug 31, 2023 · d1bd874 · d1bd874
1 parent c32cd81
commit d1bd874
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Showing 3 changed files with 17 additions and 2 deletions.
diff --git a/changelog.in b/changelog.in
@@ -77,6 +77,14 @@ Rank:   minor
 [DESCRIPTION]
 Correctly unshare variables for inverse constraint.
 
+[ENTRY]
+Module: flatzinc
+What:   bug
+Issue:  170
+Rank:   minor
+[DESCRIPTION]
+Correctly unshare variables for div and mod constraints.
+
 [ENTRY]
 Module: flatzinc
 What:   bug

diff --git a/gecode/flatzinc/registry.cpp b/gecode/flatzinc/registry.cpp
@@ -469,13 +469,17 @@ namespace Gecode { namespace FlatZinc {
       IntVar x0 = s.arg2IntVar(ce[0]);
       IntVar x1 = s.arg2IntVar(ce[1]);
       IntVar x2 = s.arg2IntVar(ce[2]);
-      div(s,x0,x1,x2, s.ann2ipl(ann));
+      IntVarArgs x = {x0, x1, x2};
+      unshare(s, x);
+      div(s,x[0],x[1],x[2], s.ann2ipl(ann));
     }
     void p_int_mod(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {
       IntVar x0 = s.arg2IntVar(ce[0]);
       IntVar x1 = s.arg2IntVar(ce[1]);
       IntVar x2 = s.arg2IntVar(ce[2]);
-      mod(s,x0,x1,x2, s.ann2ipl(ann));
+      IntVarArgs x = {x0, x1, x2};
+      unshare(s, x);
+      mod(s,x[0],x[1],x[2], s.ann2ipl(ann));
     }
 
     void p_int_min(FlatZincSpace& s, const ConExpr& ce, AST::Node* ann) {

diff --git a/gecode/int/arithmetic.cpp b/gecode/int/arithmetic.cpp
@@ -327,6 +327,9 @@ namespace Gecode {
   divmod(Home home, IntVar x0, IntVar x1, IntVar x2, IntVar x3,
          IntPropLevel) {
     using namespace Int;
+    IntVarArgs allvars = {x0, x1, x2, x3};
+    if (same(allvars))
+      throw ArgumentSame("Int::divmod");
     GECODE_POST;
 
     IntVar prod(home, Int::Limits::min, Int::Limits::max);