diff --git a/mlir/lib/Analysis/Presburger/PresburgerSet.cpp b/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
--- a/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
+++ b/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
@@ -523,8 +523,10 @@
 
   IntegerPolyhedron &a = polyhedrons[i];
   IntegerPolyhedron &b = polyhedrons[j];
-  assert(a.getNumLocalIds() == 0 && b.getNumLocalIds() == 0 &&
-         "Locals are not yet supported!");
+  /// Handling of local ids is not yet implemented, so these cases are skipped.
+  /// TODO: implement local id support.
+  if (a.getNumLocalIds() != 0 || b.getNumLocalIds() != 0)
+    return failure();
   Simplex &simpA = simplices[i];
   Simplex &simpB = simplices[j];
 
diff --git a/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp b/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
--- a/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
+++ b/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
@@ -645,6 +645,25 @@
   expectCoalesce(3, set);
 }
 
+TEST(SetTest, coalesceDiv) {
+  PresburgerSet set =
+      parsePresburgerSetFromPolyStrings(1, {
+                                               "(x) : (x floordiv 2 == 0)",
+                                               "(x) : (x floordiv 2 - 1 == 0)",
+                                           });
+  expectCoalesce(2, set);
+}
+
+TEST(SetTest, coalesceDivOtherContained) {
+  PresburgerSet set =
+      parsePresburgerSetFromPolyStrings(1, {
+                                               "(x) : (x floordiv 2 == 0)",
+                                               "(x) : (x == 0)",
+                                               "(x) : (x >= 0, -x + 1 >= 0)",
+                                           });
+  expectCoalesce(2, set);
+}
+
 static void
 expectComputedVolumeIsValidOverapprox(const PresburgerSet &set,
                                       Optional<uint64_t> trueVolume,