diff --git a/kernels/builders/primrefgen_presplit.h b/kernels/builders/primrefgen_presplit.h
index db9010995d..a63371235d 100644
--- a/kernels/builders/primrefgen_presplit.h
+++ b/kernels/builders/primrefgen_presplit.h
@@ -116,7 +116,7 @@ namespace embree
 	const float area_aabb  = area(ref.bounds());
 	const float area_prim  = primitiveArea(ref);
         if (area_prim == 0.0f) return 0.0f;
-        const unsigned int diff = 31 - lzcnt(mc.x^mc.y);
+        const int diff = 31 - lzcnt(mc.x^mc.y);
         //assert(area_prim <= area_aabb); // may trigger due to numerical issues 
         const float area_diff = max(0.0f, area_aabb - area_prim);
         //const float priority = powf(area_diff * powf(PRIORITY_SPLIT_POS_WEIGHT,(float)diff),1.0f/4.0f);   
@@ -287,7 +287,10 @@ namespace embree
         },[](const float& a, const float& b) -> float { return a+b; });
 
       /* compute number of splits per primitive */
-      const float inv_psum = 1.0f / psum;
+      float inv_psum = 1.0f;
+      if (psum > 0.0) {
+        inv_psum = 1.0f / psum;
+      }
       parallel_for( size_t(0), numPrimitives, size_t(MIN_STEP_SIZE), [&](const range<size_t>& r) -> void {
           for (size_t i=r.begin(); i<r.end(); i++)
           {
diff --git a/kernels/subdiv/half_edge.h b/kernels/subdiv/half_edge.h
index baf019cd79..8cb4f24845 100644
--- a/kernels/subdiv/half_edge.h
+++ b/kernels/subdiv/half_edge.h
@@ -316,6 +316,7 @@ namespace embree
         const Vec3fa v = vertices[p->getStartVertexIndex()];
         if (!isvalid(v)) return false;
       }
+      if (n < 2) return false;
       N += n-2;
       return n >= 3 && n <= MAX_PATCH_VALENCE;
     }
diff --git a/tutorials/buildbench/buildbench_device.cpp b/tutorials/buildbench/buildbench_device.cpp
index d0deba1992..20abbac68b 100644
--- a/tutorials/buildbench/buildbench_device.cpp
+++ b/tutorials/buildbench/buildbench_device.cpp
@@ -219,10 +219,14 @@ namespace embree {
       FATAL("unknown flags");
 
     if (iterations == 0) iterations = 1;
+    if (time != 0.0) {
     std::cout << iterations << " iterations, " << primitives << " primitives, " << objects << " objects, "
               << time/iterations << " s, "
               << 1.0 / (time/iterations) * primitives / 1000000.0 << " Mprims/s" << std::endl;
-
+    }
+    else {
+      std::cout << "error: measured build time of 0!\n";
+    }
     rtcReleaseScene (scene);
   }
   
@@ -523,10 +527,11 @@ namespace embree {
       }
 
       if (iterations == 0) iterations = 1;
-      std::cout << primitives << " primitives, " << objects << " objects, "
-                << time/iterations << " s, "
-                << 1.0 / (time/iterations) * primitives / 1000000.0 << " Mprims/s" << std::endl;
-
+      if (time > 0.0) {
+        std::cout << primitives << " primitives, " << objects << " objects, "
+                  << time/iterations << " s, "
+                  << 1.0 / (time/iterations) * primitives / 1000000.0 << " Mprims/s" << std::endl;
+      }
       rtcReleaseScene(helper.scene);
     }
 
diff --git a/tutorials/common/image/tinyexr.h b/tutorials/common/image/tinyexr.h
index a3aa50db54..54fa1b5644 100644
--- a/tutorials/common/image/tinyexr.h
+++ b/tutorials/common/image/tinyexr.h
@@ -6717,20 +6717,22 @@ int LoadEXRFromMemory(float **out_rgba, int *width, int *height,
 
     if (idxR == -1) {
       tinyexr::SetErrorMessage("R channel not found", err);
-
-      // @todo { free exr_image }
+      FreeEXRHeader(&exr_header);
+      FreeEXRImage(&exr_image);
       return TINYEXR_ERROR_INVALID_DATA;
     }
 
     if (idxG == -1) {
       tinyexr::SetErrorMessage("G channel not found", err);
-      // @todo { free exr_image }
+      FreeEXRHeader(&exr_header);
+      FreeEXRImage(&exr_image);
       return TINYEXR_ERROR_INVALID_DATA;
     }
 
     if (idxB == -1) {
       tinyexr::SetErrorMessage("B channel not found", err);
-      // @todo { free exr_image }
+      FreeEXRHeader(&exr_header);
+      FreeEXRImage(&exr_image);
       return TINYEXR_ERROR_INVALID_DATA;
     }
 
diff --git a/tutorials/common/scenegraph/materials.h b/tutorials/common/scenegraph/materials.h
index f966096dd2..335cba8aa8 100644
--- a/tutorials/common/scenegraph/materials.h
+++ b/tutorials/common/scenegraph/materials.h
@@ -109,11 +109,11 @@ namespace embree
         map_d(nullptr), map_Ka(nullptr), map_Kd(nullptr), map_Ks(nullptr), map_Kt(nullptr), map_Ns(nullptr), map_Displ(nullptr) {}
 
     OBJMaterial (float d, const std::shared_ptr<Texture> map_d,
-                 const Vec3fa& Ka, const std::shared_ptr<Texture> map_Ka, 
-                 const Vec3fa& Kd, const std::shared_ptr<Texture> map_Kd, 
-                 const Vec3fa& Ks, const std::shared_ptr<Texture> map_Ks,
-                 const Vec3fa& Kt, const std::shared_ptr<Texture> map_Kt, 
-                 const float Ns, const std::shared_ptr<Texture> map_Ns, 
+                 const Vec3fa& Ka, const std::shared_ptr<Texture> &map_Ka,
+                 const Vec3fa& Kd, const std::shared_ptr<Texture> &map_Kd,
+                 const Vec3fa& Ks, const std::shared_ptr<Texture> &map_Ks,
+                 const Vec3fa& Kt, const std::shared_ptr<Texture> &map_Kt,
+                 const float Ns, const std::shared_ptr<Texture> &map_Ns,
                  const std::shared_ptr<Texture> map_Displ)
       : base(MATERIAL_OBJ), illum(0), d(d), Ns(Ns), Ni(1.f), Ka(Ka), Kd(Kd), Ks(Ks), Kt(Kt), 
       map_d(nullptr), map_Ka(nullptr), map_Kd(nullptr), map_Ks(nullptr), map_Kt(nullptr), map_Ns(nullptr), map_Displ(nullptr),
diff --git a/tutorials/common/scenegraph/obj_loader.cpp b/tutorials/common/scenegraph/obj_loader.cpp
index f23f33f1b4..17deb2496a 100644
--- a/tutorials/common/scenegraph/obj_loader.cpp
+++ b/tutorials/common/scenegraph/obj_loader.cpp
@@ -199,7 +199,7 @@ namespace embree
           face.push_back(vtx);
           parseSepOpt(token);
         }
-        curGroup.push_back(face);
+        curGroup.emplace_back(face);
         continue;
       }
 
@@ -230,7 +230,7 @@ namespace embree
           hair[3*i+0].w = r;
           if (i != N) hair[3*i+1].w = r;
         }
-        curGroupHair.push_back(hair);
+        curGroupHair.emplace_back(hair);
       }
       
       /*! parse edge crease */
diff --git a/tutorials/common/scenegraph/ply_loader.cpp b/tutorials/common/scenegraph/ply_loader.cpp
index be31c81140..20d18c3430 100644
--- a/tutorials/common/scenegraph/ply_loader.cpp
+++ b/tutorials/common/scenegraph/ply_loader.cpp
@@ -118,7 +118,7 @@ namespace embree
           if (line == "end_header") break;
           if (line.find_first_of('#') == 0) continue;
           if (line == "") continue;
-          header.push_back(line);
+          header.emplace_back(line);
         }
 
         /* parse header */
@@ -191,7 +191,7 @@ namespace embree
           Type ty = parseType(line);
           std::string name; line >> name;
           elt.type[name] = ty; 
-          elt.properties.push_back(name);
+          elt.properties.emplace_back(name);
         }
 
         mesh.elements[name] = elt;
@@ -267,7 +267,7 @@ namespace embree
         std::vector<size_t> lst;
         size_t num = loadInteger(index_ty);
         for (size_t i=0; i<num; i++) lst.push_back(loadInteger(data_ty));
-        vec.push_back(lst);
+        vec.emplace_back(lst);
       }
 
       /* load a data element */
diff --git a/tutorials/common/scenegraph/scenegraph.h b/tutorials/common/scenegraph/scenegraph.h
index 6f043fc80d..41e067c660 100644
--- a/tutorials/common/scenegraph/scenegraph.h
+++ b/tutorials/common/scenegraph/scenegraph.h
@@ -993,7 +993,7 @@ namespace embree
     struct AnimatedLightNode : public LightNode
     {
       AnimatedLightNode (const std::vector<Ref<LightNode>>&& lights, BBox1f time_range)
-        : lights(lights), time_range(time_range) {}
+        : lights(std::move(lights)), time_range(time_range) {}
 
       virtual LightType getType() const {
         return lights[0]->getType();
diff --git a/tutorials/common/scenegraph/texture.cpp b/tutorials/common/scenegraph/texture.cpp
index 9c1302aa93..d2f25810ab 100644
--- a/tutorials/common/scenegraph/texture.cpp
+++ b/tutorials/common/scenegraph/texture.cpp
@@ -21,8 +21,8 @@ namespace embree
   Texture::Texture () 
     : width(-1), height(-1), format(INVALID), bytesPerTexel(0), width_mask(0), height_mask(0), data(nullptr) {}
   
-  Texture::Texture(Ref<Image> img, const std::string fileName)
-    : width(unsigned(img->width)), height(unsigned(img->height)), format(RGBA8), bytesPerTexel(4), width_mask(0), height_mask(0), data(nullptr), fileName(fileName)
+  Texture::Texture(Ref<Image> img, std::string &&fileName)
+    : width(unsigned(img->width)), height(unsigned(img->height)), format(RGBA8), bytesPerTexel(4), width_mask(0), height_mask(0), data(nullptr), fileName(std::move(fileName))
   {
     width_mask  = isPowerOf2(width) ? width-1 : 0;
     height_mask = isPowerOf2(height) ? height-1 : 0;
diff --git a/tutorials/common/scenegraph/texture.h b/tutorials/common/scenegraph/texture.h
index 4f3e71da97..f53b97497a 100644
--- a/tutorials/common/scenegraph/texture.h
+++ b/tutorials/common/scenegraph/texture.h
@@ -41,7 +41,7 @@ namespace embree
     
   public:
     Texture (); 
-    Texture (Ref<Image> image, const std::string fileName); 
+    Texture (Ref<Image> image, std::string &&fileName); 
     Texture (unsigned width, unsigned height, const Format format, const char* in = nullptr);
     ~Texture ();
 
diff --git a/tutorials/common/scenegraph/xml_loader.cpp b/tutorials/common/scenegraph/xml_loader.cpp
index af0ac1cc2f..479844aee8 100644
--- a/tutorials/common/scenegraph/xml_loader.cpp
+++ b/tutorials/common/scenegraph/xml_loader.cpp
@@ -77,7 +77,7 @@ namespace embree
     Variant (const std::string& str) : type(STRING), str(str) {}
 
     /*! Constructs a variant object holding a texture value. */
-    Variant (const std::shared_ptr<Texture> tex) : type(TEXTURE), texture(tex) {}
+    Variant (const std::shared_ptr<Texture> tex) : type(TEXTURE), texture(std::move(tex)) {}
 
     /*! Extracts a boolean from the variant type. */
     bool  getBool () const { return b[0]; }
@@ -1371,7 +1371,7 @@ namespace embree
 
       data[i++] = Vec3fa(0, r, 0);
       data[i++] = Vec3fa(0, -r, 0);
-      mesh->positions.push_back(data);
+      mesh->positions.emplace_back(data);
     }
 
     {
@@ -1500,10 +1500,10 @@ namespace embree
           }
       }
 
-      hairs->positions.push_back(pos);
-      if (is_normaloriented) hairs->normals.push_back(norm);
-      if (is_hermite) hairs->tangents.push_back(tans);
-      if (is_hermite && is_normaloriented) hairs->dnormals.push_back(dnorm);
+      hairs->positions.emplace_back(pos);
+      if (is_normaloriented) hairs->normals.emplace_back(norm);
+      if (is_hermite) hairs->tangents.emplace_back(tans);
+      if (is_hermite && is_normaloriented) hairs->dnormals.emplace_back(dnorm);
 
       // linear uses 3 segments per hair
       if (is_linear) {
diff --git a/tutorials/common/tutorial/benchmark_render.h b/tutorials/common/tutorial/benchmark_render.h
index 54a2ce2457..4b56f98d68 100644
--- a/tutorials/common/tutorial/benchmark_render.h
+++ b/tutorials/common/tutorial/benchmark_render.h
@@ -109,7 +109,7 @@ static void renderBenchmarkLegacy(BenchState& state, BenchParams& params ,int ar
       if (numTotalFrames >= 1024 && (i % 64 == 0))
       {
         double rate = 0;
-        if (fpsStat.getAvg()) rate = 100.0f*fpsStat.getSigma()/fpsStat.getAvg();
+        if (fpsStat.getAvg() != 0.0) rate = 100.0f*fpsStat.getSigma()/fpsStat.getAvg();
 
         std::cout << "frame [" << std::setw(3) << i << " / " << std::setw(3) << numTotalFrames << "]: "
                   << std::setw(8) << fps << " fps, "
diff --git a/tutorials/external/catch.hpp b/tutorials/external/catch.hpp
index 8c4cfe478c..05afd4535d 100644
--- a/tutorials/external/catch.hpp
+++ b/tutorials/external/catch.hpp
@@ -4635,7 +4635,7 @@ namespace Catch {
                 TestSpec::PatternPtr pattern = std::make_shared<T>( token );
                 if( m_exclusion )
                     pattern = std::make_shared<TestSpec::ExcludedPattern>( pattern );
-                m_currentFilter.m_patterns.push_back( pattern );
+                m_currentFilter.m_patterns.emplace_back( pattern );
             }
             m_exclusion = false;
             m_mode = None;
diff --git a/tutorials/next_hit/next_hit_device.cpp b/tutorials/next_hit/next_hit_device.cpp
index b723525f2a..0978c6bb6b 100644
--- a/tutorials/next_hit/next_hit_device.cpp
+++ b/tutorials/next_hit/next_hit_device.cpp
@@ -26,12 +26,13 @@ RTCFeatureFlags g_feature_mask;
 struct HitList
 {
   HitList (const TutorialData& data)
-    : data(data), begin(0), end(0) {}
+    : data(data), begin(0), end(0) {
+    }
 
   /* Hit structure that defines complete order over hits */
   struct Hit
   {
-    Hit() {}
+    Hit() : opaque(false), t(0.0f), primID(RTC_INVALID_GEOMETRY_ID), geomID(RTC_INVALID_GEOMETRY_ID), instID(RTC_INVALID_GEOMETRY_ID) {}
 
     Hit (bool opaque, float t, unsigned int primID = 0xFFFFFFFF, unsigned int geomID = 0xFFFFFFFF, unsigned int instID = 0xFFFFFFFF)
       : opaque(opaque), t(t), primID(primID), geomID(geomID), instID(instID) {}
@@ -317,6 +318,10 @@ Vec3ff renderPixelStandard(const TutorialData& data, float x, float y,
   
   /* initialize ray */
   Ray ray(Vec3fa(camera.xfm.p), Vec3fa(normalize(x*camera.xfm.l.vx + y*camera.xfm.l.vy + camera.xfm.l.vz)), 0.0f, inf, 0.0f);
+  ray.Ng = {0.0f, 1.0f, 0.0f};
+  ray.flags = 0;
+  ray.id = 0;
+  ray.u = ray.v = 0.0f;
 
   /* either gather hits in single pass or using multiple passes */
   HitList hits(data);
diff --git a/tutorials/verify/verify.cpp b/tutorials/verify/verify.cpp
index 1839da439d..cb1edc00aa 100644
--- a/tutorials/verify/verify.cpp
+++ b/tutorials/verify/verify.cpp
@@ -7074,15 +7074,16 @@ namespace embree
     plot << "set title \"" << outFileName.name() << "\"" << std::endl; 
     plot << "set xlabel \"" + xlabel + "\"" << std::endl;
     if (f != 1.0f) plot << "set logscale x" << std::endl;
-    if (benchmarks.size())
+    if (benchmarks.size()) {
       plot << "set ylabel \"" << benchmarks[0]->unit << "\"" << std::endl;
-    plot << "set yrange [0:]" << std::endl;
+      plot << "set yrange [0:]" << std::endl;
 
-    plot << "plot \\" << std::endl;
-    for (size_t i=0; i<benchmarks.size(); i++) {
-      plot << "\"" << outFileName.name() << "." << benchmarks[i]->name << ".txt\" using 1:2 title \"" << benchmarks[i]->name << "\" with lines";
-      if (i != benchmarks.size()-1) plot << ",\\";
-      plot << std::endl;
+      plot << "plot \\" << std::endl;
+      for (size_t i=0; i<benchmarks.size(); i++) {
+        plot << "\"" << outFileName.name() << "." << benchmarks[i]->name << ".txt\" using 1:2 title \"" << benchmarks[i]->name << "\" with lines";
+        if (i != benchmarks.size()-1) plot << ",\\";
+        plot << std::endl;
+      }
     }
     plot << std::endl;
     plot.close();