diff --git a/rtengine/FTblockDN.cc b/rtengine/FTblockDN.cc
index e0d22d639..c74e49218 100644
--- a/rtengine/FTblockDN.cc
+++ b/rtengine/FTblockDN.cc
@@ -1677,10 +1677,7 @@ SSEFUNCTION void ImProcFunctions::RGB_denoise(int kall, Imagefloat * src, Imagef
                         }
 
                         delete labdn;
-
-                        if (Lin) {
-                            delete Lin;
-                        }
+                        delete Lin;
 
                     }//end of tile row
                 }//end of tile loop
diff --git a/rtengine/lcp.cc b/rtengine/lcp.cc
index 1ed601301..0f45e1270 100644
--- a/rtengine/lcp.cc
+++ b/rtengine/lcp.cc
@@ -276,7 +276,7 @@ float LCPMapper::calcVignetteFac(int x, int y) const
                                                    + 2.*aVig[0] * aVig[2] - 3.*param0Sqr * aVig[1]) * rsqr * rsqr));
 }
 
-LCPProfile::LCPProfile(Glib::ustring fname)
+LCPProfile::LCPProfile(const Glib::ustring &fname)
 {
     const int BufferSize = 8192;
     char buf[BufferSize];
diff --git a/rtengine/lcp.h b/rtengine/lcp.h
index 15d51d556..908bacf56 100644
--- a/rtengine/lcp.h
+++ b/rtengine/lcp.h
@@ -89,7 +89,7 @@ public:
     static const int MaxPersModelCount = 3000;
     LCPPersModel* aPersModel[MaxPersModelCount];  // Do NOT use std::list or something, it's buggy in GCC!
 
-    explicit LCPProfile(Glib::ustring fname);
+    explicit LCPProfile(const Glib::ustring &fname);
 
     void calcParams(int mode, float focalLength, float focusDist, float aperture, LCPModelCommon *pCorr1, LCPModelCommon *pCorr2, LCPModelCommon *pCorr3) const;  // Interpolates between the persModels frames
 
diff --git a/rtgui/ilabel.cc b/rtgui/ilabel.cc
index 591564305..2c7edfd80 100644
--- a/rtgui/ilabel.cc
+++ b/rtgui/ilabel.cc
@@ -18,7 +18,7 @@
  */
 #include "ilabel.h"
 
-ILabel::ILabel (Glib::ustring lab) : label(lab) {}
+ILabel::ILabel (const Glib::ustring &lab) : label(lab) {}
 
 void ILabel::on_realize()
 {
diff --git a/rtgui/ilabel.h b/rtgui/ilabel.h
index ab8f656cc..82064bd23 100644
--- a/rtgui/ilabel.h
+++ b/rtgui/ilabel.h
@@ -27,7 +27,7 @@ class ILabel : public Gtk::DrawingArea
     Glib::ustring label;
 
 public:
-    explicit ILabel (Glib::ustring lab);
+    explicit ILabel (const Glib::ustring &lab);
     bool on_expose_event(GdkEventExpose* event);
     void on_realize();
     void on_style_changed (const Glib::RefPtr<Gtk::Style>& style);
diff --git a/rtgui/partialpastedlg.cc b/rtgui/partialpastedlg.cc
index d017b5409..78631b725 100644
--- a/rtgui/partialpastedlg.cc
+++ b/rtgui/partialpastedlg.cc
@@ -20,7 +20,7 @@
 #include "multilangmgr.h"
 #include "paramsedited.h"
 
-PartialPasteDlg::PartialPasteDlg (Glib::ustring title)
+PartialPasteDlg::PartialPasteDlg (const Glib::ustring &title)
 {
 
     set_modal (true);
diff --git a/rtgui/partialpastedlg.h b/rtgui/partialpastedlg.h
index 57d77f532..a054b042e 100644
--- a/rtgui/partialpastedlg.h
+++ b/rtgui/partialpastedlg.h
@@ -132,7 +132,7 @@ public:
     sigc::connection raw_caredConn, raw_cablueConn, raw_ca_autocorrectConn, raw_hotpix_filtConn, raw_deadpix_filtConn, raw_linenoiseConn, raw_greenthreshConn, raw_ccStepsConn, raw_methodConn, raw_dcb_iterationsConn, raw_lmmse_iterationsConn, raw_dcb_enhanceConn, raw_exposConn, raw_preserConn, raw_blackConn;
 
 public:
-    explicit PartialPasteDlg (Glib::ustring title);
+    explicit PartialPasteDlg (const Glib::ustring &title);
 
     void applyPaste (rtengine::procparams::ProcParams* dstPP, ParamsEdited* dstPE, const rtengine::procparams::ProcParams* srcPP, const ParamsEdited* srcPE = NULL);
 
diff --git a/rtgui/saveasdlg.cc b/rtgui/saveasdlg.cc
index c9490f585..2afd1eb58 100644
--- a/rtgui/saveasdlg.cc
+++ b/rtgui/saveasdlg.cc
@@ -22,7 +22,7 @@
 #include "rtimage.h"
 
 extern Options options;
-SaveAsDialog::SaveAsDialog (Glib::ustring initialDir)
+SaveAsDialog::SaveAsDialog (const Glib::ustring &initialDir)
 {
 
     set_title(M("GENERAL_SAVE"));
diff --git a/rtgui/saveasdlg.h b/rtgui/saveasdlg.h
index 188d915fb..4810b46d9 100644
--- a/rtgui/saveasdlg.h
+++ b/rtgui/saveasdlg.h
@@ -45,7 +45,7 @@ protected:
     void  putToQueueClicked ();
 
 public:
-    explicit SaveAsDialog (Glib::ustring initialDir);
+    explicit SaveAsDialog (const Glib::ustring &initialDir);
 
     Glib::ustring   getFileName        ();
     Glib::ustring   getDirectory       ();