diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 32ac06b6c1c778b20a3c35f3d0c9bc6c93a12647..cbb10dab60468e394719c75a743cc743424e9364 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-11-02  Tom de Vries  <tom@codesourcery.com>
+
+	PR tree-optimization/50672
+	* g++.dg/pr50672.C: New test.
+
 2011-11-02  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.target/i386/avx-cvt-2.c (dg-options): Add -mtune=generic.
diff --git a/gcc/testsuite/g++.dg/pr50672.C b/gcc/testsuite/g++.dg/pr50672.C
new file mode 100644
index 0000000000000000000000000000000000000000..fb310082edc92eb8c5a9f36024672d5ba370c92a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr50672.C
@@ -0,0 +1,101 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-tail-merge" } */
+typedef int BoxCoordinate;
+typedef int BoxDimension;
+const BoxDimension X = 0;
+const BoxDimension Y = 1;
+const BoxDimension NDimensions = 2;
+class BoxPoint {
+    BoxCoordinate point[NDimensions];
+public:
+    bool isValid() const;
+    void operator += (const BoxPoint& p)     {
+        if (isValid() && p.isValid())  {
+            point[X] += p.point[X];
+        }
+    }
+    const BoxCoordinate& operator [] (const BoxDimension& dimension) const {
+        return point[dimension];
+    }
+};
+class BoxRegion {
+public:
+    BoxCoordinate& origin(BoxDimension d) const;
+    BoxCoordinate& space(BoxDimension d) const;
+};
+inline bool operator <= (const BoxPoint& p, const BoxRegion& r) {
+    for (BoxDimension d = X;
+         d <= Y;
+         d++)  if (p[d] < r.origin(d) || p[d] >= r.origin(d) + r.space(d))     
+return false;
+    return true;
+}
+typedef struct _WidgetRec *Widget;
+struct GraphGC {
+    BoxPoint offsetIfSelected;
+};
+class GraphNode;
+class GraphEdge {
+public:
+    GraphNode *from() const;
+    GraphNode *to() const;
+};
+class LineGraphEdge: public GraphEdge {
+protected:
+    virtual void drawLine(Widget w,      const GraphGC& gc) const;
+    void _print(const GraphGC &gc) const;
+};
+class ArcGraphEdge: public LineGraphEdge {
+    static bool center(const BoxPoint& p1, const BoxPoint& p2,
+                       const BoxPoint& p3, double& x, double& y);
+    void makeLine(Widget w,     const GraphGC& gc) const;
+};
+class GraphNode {
+public:
+    bool& selected();
+    GraphEdge *firstTo() const;
+    GraphEdge *nextTo(GraphEdge *ref) const;
+    virtual const BoxPoint& pos() const = 0;
+    virtual const BoxRegion& region(const GraphGC& gc) const = 0;
+    virtual bool isHint() const;
+};
+class PosGraphNode: public GraphNode { };
+class RegionGraphNode: public PosGraphNode { };
+class HintGraphNode: public RegionGraphNode { };
+void ArcGraphEdge::makeLine(Widget w, const GraphGC& gc) const {
+    HintGraphNode *arc_hint = 0;
+    RegionGraphNode *arc_from = 0;
+    RegionGraphNode *arc_to = 0;
+    bool make_arc = true;
+    if (from()->isHint() && to()->isHint())     {
+        make_arc = false;
+    }
+    else if (from()->isHint() && from()->firstTo() != 0)     {
+        if (arc_hint == 0 || arc_from == 0 || arc_to == 0
+            || arc_hint->nextTo(arc_hint->firstTo()) != 0)  {
+            make_arc = false;
+        }
+    }
+    if (!make_arc)     {
+        if (w != 0)      LineGraphEdge::drawLine(w, gc);
+        else      LineGraphEdge::_print(gc);
+        return;
+    }
+    BoxPoint pos_from = arc_from->pos();
+    BoxRegion region_from = arc_from->region(gc);
+    BoxPoint pos_to = arc_to->pos();
+    BoxRegion region_to = arc_to->region(gc);
+    BoxPoint pos_hint = arc_hint->pos();
+    if (arc_hint->selected())     {
+        pos_hint += gc.offsetIfSelected;
+    }
+    if (pos_hint <= region_from || pos_hint <= region_to)     {
+        return;
+    }
+    double cx, cy;
+    bool ok = center(pos_from, pos_hint, pos_to, cx, cy);
+    if (!ok)     {
+        if (w != 0)      LineGraphEdge::drawLine(w, gc);
+        else      LineGraphEdge::_print(gc);
+    }
+}