diff --git a/CMakeLists.txt b/CMakeLists.txt
index f60c8bde6..6f2332ce0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -162,7 +162,7 @@ if (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUXX)
     endif ()
 endif()
 
-if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     add_compile_options(-Wall)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-reorder" )
 
@@ -170,7 +170,7 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMPILER_ID}" STRE
     add_compile_options(-Werror=return-type)
 
     #removes LOTS of extraneous Eigen warnings (GCC only supports it since 6.1)
-    #if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6.1)
+    #if("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6.1)
         # add_compile_options(-Wno-ignored-attributes) # Tamas: Eigen include dirs are marked as SYSTEM
     #endif()
 
diff --git a/src/libslic3r/Utils.hpp b/src/libslic3r/Utils.hpp
index 09e24a475..8a4f1424b 100644
--- a/src/libslic3r/Utils.hpp
+++ b/src/libslic3r/Utils.hpp
@@ -172,7 +172,7 @@ extern std::string xml_escape(std::string text);
 #if defined __GNUC__ && __GNUC__ < 5 && !defined __clang__
 // Older GCCs don't have std::is_trivially_copyable
 // cf. https://gcc.gnu.org/onlinedocs/gcc-4.9.4/libstdc++/manual/manual/status.html#status.iso.2011
-#warning "GCC version < 5, faking std::is_trivially_copyable"
+// #warning "GCC version < 5, faking std::is_trivially_copyable"
 template<typename T> struct IsTriviallyCopyable { static constexpr bool value = true; };
 #else
 template<typename T> struct IsTriviallyCopyable : public std::is_trivially_copyable<T> {};
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
index 4b975e87e..a65074646 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
@@ -166,7 +166,7 @@ void GLGizmoBase::set_highlight_color(const float* color)
 
 void GLGizmoBase::enable_grabber(unsigned int id)
 {
-    if ((0 <= id) && (id < (unsigned int)m_grabbers.size()))
+    if (id < m_grabbers.size())
         m_grabbers[id].enabled = true;
 
     on_enable_grabber(id);
@@ -174,7 +174,7 @@ void GLGizmoBase::enable_grabber(unsigned int id)
 
 void GLGizmoBase::disable_grabber(unsigned int id)
 {
-    if ((0 <= id) && (id < (unsigned int)m_grabbers.size()))
+    if (id < m_grabbers.size())
         m_grabbers[id].enabled = false;
 
     on_disable_grabber(id);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoRotate.hpp b/src/slic3r/GUI/Gizmos/GLGizmoRotate.hpp
index 7846edb22..8733c9a11 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoRotate.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoRotate.hpp
@@ -93,19 +93,19 @@ protected:
     }
     virtual void on_set_hover_id()
     {
-        for (unsigned int i = 0; i < 3; ++i)
+        for (int i = 0; i < 3; ++i)
         {
             m_gizmos[i].set_hover_id((m_hover_id == i) ? 0 : -1);
         }
     }
     virtual void on_enable_grabber(unsigned int id)
     {
-        if ((0 <= id) && (id < 3))
+        if (id < 3)
             m_gizmos[id].enable_grabber(0);
     }
     virtual void on_disable_grabber(unsigned int id)
     {
-        if ((0 <= id) && (id < 3))
+        if (id < 3)
             m_gizmos[id].disable_grabber(0);
     }
     virtual void on_start_dragging();
diff --git a/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp b/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
index 2aaf55424..d96b806e5 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
@@ -223,7 +223,7 @@ void GLGizmosManager::update_data()
     enable_grabber(Rotate, 1, !is_wipe_tower);
 
     bool enable_scale_xyz = selection.is_single_full_instance() || selection.is_single_volume() || selection.is_single_modifier();
-    for (int i = 0; i < 6; ++i)
+    for (unsigned int i = 0; i < 6; ++i)
     {
         enable_grabber(Scale, i, enable_scale_xyz);
     }
diff --git a/src/slic3r/GUI/wxExtensions.hpp b/src/slic3r/GUI/wxExtensions.hpp
index 9a6460dcb..a704f79d7 100644
--- a/src/slic3r/GUI/wxExtensions.hpp
+++ b/src/slic3r/GUI/wxExtensions.hpp
@@ -323,9 +323,9 @@ public:
 	}
 
 	bool SwapChildrens(int frst_id, int scnd_id) {
-		if (GetChildCount() < 2 || 
-			frst_id < 0 || frst_id >= GetChildCount() || 
-			scnd_id < 0 || scnd_id >= GetChildCount())
+		if (GetChildCount() < 2 ||
+			frst_id < 0 || (size_t)frst_id >= GetChildCount() ||
+			scnd_id < 0 || (size_t)scnd_id >= GetChildCount())
 			return false;
 
 		ObjectDataViewModelNode new_scnd = *GetNthChild(frst_id);