diff --git a/src/libslic3r/EdgeGrid.cpp b/src/libslic3r/EdgeGrid.cpp
index 4985b788e4..c1c8fbcd98 100644
--- a/src/libslic3r/EdgeGrid.cpp
+++ b/src/libslic3r/EdgeGrid.cpp
@@ -1307,9 +1307,9 @@ Polygons EdgeGrid::Grid::contours_simplified(coord_t offset, bool fill_holes) co
 	// 1) Collect the lines.
 	std::vector<Line> lines;
 	EndPointMapType start_point_to_line_idx;
-	for (int r = 0; r <= int(m_rows); ++ r) {
-		for (int c = 0; c <= int(m_cols); ++ c) {
-			int  addr    = (r + 1) * cell_cols + c + 1;
+	for (coord_t r = 0; r <= coord_t(m_rows); ++ r) {
+		for (coord_t c = 0; c <= coord_t(m_cols); ++ c) {
+			size_t  addr    = (r + 1) * cell_cols + c + 1;
 			bool left    = cell_inside[addr - 1];
 			bool top     = cell_inside[addr - cell_cols];
 			bool current = cell_inside[addr];
diff --git a/src/libslic3r/libslic3r.h b/src/libslic3r/libslic3r.h
index 86d9241656..e95222f502 100644
--- a/src/libslic3r/libslic3r.h
+++ b/src/libslic3r/libslic3r.h
@@ -40,7 +40,7 @@
 using coord_t = int32_t;
 #else
 //FIXME At least FillRectilinear2 and std::boost Voronoi require coord_t to be 32bit.
-typedef int64_t coord_t;
+using coord_t = int64_t;
 #endif
 
 using coordf_t = double;
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 1191bf55f3..b4778e3932 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -5065,8 +5065,11 @@ std::vector<Vec2f> GLCanvas3D::get_empty_cells(const Vec2f start_point, const Ve
     Vec2d vmin(build_volume.min.x(), build_volume.min.y()), vmax(build_volume.max.x(), build_volume.max.y());
     BoundingBoxf bbox(vmin, vmax);
     std::vector<Vec2f> cells;
+    std::vector<Vec2f> cells_ret;
     auto min_x = start_point.x() - step(0) * int((start_point.x() - bbox.min.x()) / step(0));
     auto min_y = start_point.y() - step(1) * int((start_point.y() - bbox.min.y()) / step(1));
+    cells.reserve(((bbox.max.x() - min_x) / step(0)) * ((bbox.max.y() - min_y) / step(1)));
+    cells_ret.reserve(cells.size());
     for (float x = min_x; x < bbox.max.x() - step(0) / 2; x += step(0))
         for (float y = min_y; y < bbox.max.y() - step(1) / 2; y += step(1))
         {
@@ -5093,10 +5096,10 @@ std::vector<Vec2f> GLCanvas3D::get_empty_cells(const Vec2f start_point, const Ve
 
             for (auto it = cells.begin(); it != cells.end(); )
             {
-                if (inst_hull_2d.contains(Point(scale_(it->x()), scale_(it->y()))))
-                    it = cells.erase(it);
-                else
-                    it++;
+                if (!inst_hull_2d.contains(Point(scale_(it->x()), scale_(it->y()))))
+                    cells_ret.push_back(*it);
+
+                it++;
             }
         }
     }
@@ -5106,8 +5109,8 @@ std::vector<Vec2f> GLCanvas3D::get_empty_cells(const Vec2f start_point, const Ve
         start(0) = bbox.center()(0);
         start(1) = bbox.center()(1);
     }
-    std::sort(cells.begin(), cells.end(), [start](const Vec2f& cell1, const Vec2f& cell2) {return (cell1 - start).norm() < (cell2 - start).norm(); });
-    return cells;
+    std::sort(cells_ret.begin(), cells_ret.end(), [start](const Vec2f& cell1, const Vec2f& cell2) {return (cell1 - start).norm() < (cell2 - start).norm(); });
+    return cells_ret;
 }
 
 Vec2f GLCanvas3D::get_nearest_empty_cell(const Vec2f start_point, const Vec2f step)