Added a ScopedNoDenormal class to temporarily disable denormals

examples/DSP module plugin demo/DSP module plugin demo.jucer

@@ -125,5 +125,5 @@
     <MODULE id="juce_gui_extra" showAllCode="1" useLocalCopy="0" useGlobalPath="0"/>
     <MODULE id="juce_opengl" showAllCode="1" useLocalCopy="0" useGlobalPath="0"/>
   </MODULES>
-  <JUCEOPTIONS JUCE_QUICKTIME="disabled"/>
+  <JUCEOPTIONS JUCE_QUICKTIME="disabled" JUCE_DSP_ENABLE_SNAP_TO_ZERO="disabled"/>
 </JUCERPROJECT>

examples/DSP module plugin demo/JuceLibraryCode/AppConfig.h

@@ -130,6 +130,10 @@
  //#define JUCE_FORCE_USE_LEGACY_PARAM_IDS 1
 #endif
 
+#ifndef    JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+ //#define JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE 1
+#endif
+
 #ifndef    JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
  //#define JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS 1
 #endif
@@ -214,6 +218,10 @@
  //#define JUCE_DSP_USE_STATIC_FFTW 1
 #endif
 
+#ifndef    JUCE_DSP_ENABLE_SNAP_TO_ZERO
+ #define   JUCE_DSP_ENABLE_SNAP_TO_ZERO 0
+#endif
+
 //==============================================================================
 // juce_events flags:
 

examples/DSP module plugin demo/Source/PluginProcessor.cpp

@@ -114,6 +114,8 @@ void DspModulePluginDemoAudioProcessor::releaseResources()
 
 void DspModulePluginDemoAudioProcessor::process (dsp::ProcessContextReplacing<float> context) noexcept
 {
+    ScopedNoDenormals noDenormals;
+
     // Input volume applied with a LinearSmoothedValue
     inputVolume.process (context);
 

extras/Projucer/JuceLibraryCode/BinaryData.cpp

@@ -1617,6 +1617,7 @@ static const unsigned char temp_binary_data_8[] =
 "\r\n"
 "void FILTERCLASSNAME::processBlock (AudioSampleBuffer& buffer, MidiBuffer& midiMessages)\r\n"
 "{\r\n"
+"    ScopedNoDenormals noDenormals;\r\n"
 "    const int totalNumInputChannels  = getTotalNumInputChannels();\r\n"
 "    const int totalNumOutputChannels = getTotalNumOutputChannels();\r\n"
 "\r\n"
@@ -7028,7 +7029,7 @@ const char* getNamedResource (const char* resourceNameUTF8, int& numBytes) throw
         case 0xafccbd3f:  numBytes = 3141; return jucer_AudioComponentTemplate_cpp;
         case 0x27c5a93a:  numBytes = 1310; return jucer_AudioPluginEditorTemplate_cpp;
         case 0x4d0721bf:  numBytes = 938; return jucer_AudioPluginEditorTemplate_h;
-        case 0x51b49ac5:  numBytes = 5611; return jucer_AudioPluginFilterTemplate_cpp;
+        case 0x51b49ac5:  numBytes = 5647; return jucer_AudioPluginFilterTemplate_cpp;
         case 0x488afa0a:  numBytes = 2245; return jucer_AudioPluginFilterTemplate_h;
         case 0xabad7041:  numBytes = 2151; return jucer_ComponentTemplate_cpp;
         case 0xfc72fe86:  numBytes = 2064; return jucer_ComponentTemplate_h;

extras/Projucer/JuceLibraryCode/BinaryData.h

@@ -33,7 +33,7 @@ namespace BinaryData
     const int            jucer_AudioPluginEditorTemplate_hSize = 938;
 
     extern const char*   jucer_AudioPluginFilterTemplate_cpp;
-    const int            jucer_AudioPluginFilterTemplate_cppSize = 5611;
+    const int            jucer_AudioPluginFilterTemplate_cppSize = 5647;
 
     extern const char*   jucer_AudioPluginFilterTemplate_h;
     const int            jucer_AudioPluginFilterTemplate_hSize = 2245;

extras/Projucer/Source/BinaryData/jucer_AudioPluginFilterTemplate.cpp

@@ -131,6 +131,7 @@ bool FILTERCLASSNAME::isBusesLayoutSupported (const BusesLayout& layouts) const
 
 void FILTERCLASSNAME::processBlock (AudioSampleBuffer& buffer, MidiBuffer& midiMessages)
 {
+    ScopedNoDenormals noDenormals;
     const int totalNumInputChannels  = getTotalNumInputChannels();
     const int totalNumOutputChannels = getTotalNumOutputChannels();
 

modules/juce_audio_basics/buffers/juce_FloatVectorOperations.h

@@ -221,4 +221,34 @@ public:
     static void JUCE_CALLTYPE disableDenormalisedNumberSupport() noexcept;
 };
 
+//==============================================================================
+/**
+     Helper class providing an RAII-based mechanism for temporarily disabling
+     denormals on your CPU.
+*/
+class ScopedNoDenormals
+{
+public:
+    inline ScopedNoDenormals() noexcept
+    {
+       #if JUCE_USE_SSE_INTRINSICS
+        mxcsr = _mm_getcsr();
+        _mm_setcsr (mxcsr | 0x8040); // add the DAZ and FZ bits
+       #endif
+    }
+
+
+    inline ~ScopedNoDenormals() noexcept
+    {
+       #if JUCE_USE_SSE_INTRINSICS
+        _mm_setcsr (mxcsr);
+       #endif
+    }
+
+private:
+    #if JUCE_USE_SSE_INTRINSICS
+     unsigned int mxcsr;
+    #endif
+};
+
 } // namespace juce

modules/juce_audio_basics/juce_audio_basics.h

@@ -51,6 +51,7 @@
 
 #include <juce_core/juce_core.h>
 
+//==============================================================================
 #undef Complex  // apparently some C libraries actually define these symbols (!)
 #undef Factor
 

modules/juce_dsp/juce_dsp.h

@@ -166,6 +166,23 @@
  #define JUCE_DSP_USE_STATIC_FFTW 0
 #endif
 
+/** Config: JUCE_DSP_ENABLE_SNAP_TO_ZERO
+
+    Enables code in the dsp module to avoid floating point denormals during the
+    processing of some of the dsp module's filters.
+
+    Enabling this will add a slight performance overhead to the DSP module's
+    filters and algorithms. If your audio app already disables denormals altogether
+    (for exmaple, by using the ScopedNoDenormals class or the
+    FloatVectorOperations::disableDenormalisedNumberSupport method), then you
+    can safely disable this flag to shave off a few cpu cycles from the DSP module's
+    filters and algorithms.
+*/
+#ifndef JUCE_DSP_ENABLE_SNAP_TO_ZERO
+ #define JUCE_DSP_ENABLE_SNAP_TO_ZERO 1
+#endif
+
+
 //==============================================================================
 #undef Complex  // apparently some C libraries actually define these symbols (!)
 #undef Factor
@@ -185,11 +202,19 @@ namespace juce
 
                 This function will work with both primitives and simple containers.
             */
+          #if JUCE_DSP_ENABLE_SNAP_TO_ZERO
             inline void snapToZero (float&       x) noexcept            { JUCE_SNAP_TO_ZERO (x); }
            #ifndef DOXYGEN
             inline void snapToZero (double&      x) noexcept            { JUCE_SNAP_TO_ZERO (x); }
             inline void snapToZero (long double& x) noexcept            { JUCE_SNAP_TO_ZERO (x); }
            #endif
+          #else
+            inline void snapToZero (float&       x) noexcept            { ignoreUnused (x); }
+           #ifndef DOXYGEN
+            inline void snapToZero (double&      x) noexcept            { ignoreUnused (x); }
+            inline void snapToZero (long double& x) noexcept            { ignoreUnused (x); }
+           #endif
+          #endif
         }
     }
 }

modules/juce_dsp/processors/juce_Oversampling.cpp

@@ -444,7 +444,7 @@ public:
                 auto numStages = coefficientsUp.size();
 
                 for (auto n = 0; n < numStages; n++)
-                    JUCE_SNAP_TO_ZERO (lv1[n]);
+                    util::snapToZero (lv1[n]);
             }
         }
         else
@@ -455,7 +455,7 @@ public:
                 auto numStages = coefficientsDown.size();
 
                 for (auto n = 0; n < numStages; n++)
-                    JUCE_SNAP_TO_ZERO (lv1[n]);
+                    util::snapToZero (lv1[n]);
             }
         }
     }