diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index a3e72994e..2e65c147e 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -32,11 +32,6 @@ sub regions {
     return [ map $self->get_region($_), 0..($self->region_count-1) ];
 }
 
-sub merge_slices {
-    my ($self) = @_;
-    $_->merge_slices for @{$self->regions};
-}
-
 sub make_perimeters {
     my $self = shift;
     Slic3r::debugf "Making perimeters for layer %d\n", $self->id;
diff --git a/xs/src/libslic3r/Layer.cpp b/xs/src/libslic3r/Layer.cpp
index 2e1a8c50e..250572fb7 100644
--- a/xs/src/libslic3r/Layer.cpp
+++ b/xs/src/libslic3r/Layer.cpp
@@ -126,6 +126,14 @@ Layer::make_slices()
     }
 }
 
+void
+Layer::merge_slices()
+{
+    FOREACH_LAYERREGION(this, layerm) {
+        (*layerm)->merge_slices();
+    }
+}
+
 template <class T>
 bool
 Layer::any_internal_region_slice_contains(const T &item) const
diff --git a/xs/src/libslic3r/Layer.hpp b/xs/src/libslic3r/Layer.hpp
index 8b2ef6f3f..d34abec36 100644
--- a/xs/src/libslic3r/Layer.hpp
+++ b/xs/src/libslic3r/Layer.hpp
@@ -95,6 +95,7 @@ class Layer {
     LayerRegion* add_region(PrintRegion* print_region);
     
     void make_slices();
+    void merge_slices();
     template <class T> bool any_internal_region_slice_contains(const T &item) const;
     template <class T> bool any_bottom_region_slice_contains(const T &item) const;
     
diff --git a/xs/xsp/Layer.xsp b/xs/xsp/Layer.xsp
index 611e2cae9..e8372206c 100644
--- a/xs/xsp/Layer.xsp
+++ b/xs/xsp/Layer.xsp
@@ -71,6 +71,7 @@
         %code%{ RETVAL = (int)(intptr_t)THIS; %};
     
     void make_slices();
+    void merge_slices();
     bool any_internal_region_slice_contains_polyline(Polyline* polyline)
         %code%{ RETVAL = THIS->any_internal_region_slice_contains(*polyline); %};
     bool any_bottom_region_slice_contains_polyline(Polyline* polyline)