diff --git a/distrho/src/DistrhoPluginInternal.hpp b/distrho/src/DistrhoPluginInternal.hpp
index 58be2ffb..8a6b91f6 100644
--- a/distrho/src/DistrhoPluginInternal.hpp
+++ b/distrho/src/DistrhoPluginInternal.hpp
@@ -225,8 +225,10 @@ public:
 #if DISTRHO_PLUGIN_WANT_PORT_GROUPS
         std::set<int32_t> portGroupIndices;
 
+#if DISTRHO_PLUGIN_NUM_INPUTS+DISTRHO_PLUGIN_NUM_OUTPUTS > 0
         for (uint32_t i=0; i < DISTRHO_PLUGIN_NUM_INPUTS+DISTRHO_PLUGIN_NUM_OUTPUTS; ++i)
             portGroupIndices.insert(fData->audioPorts[i].group);
+#endif
 
         for (uint32_t i=0, count=fData->parameterCount; i < count; ++i)
             portGroupIndices.insert(fData->parameters[i].group);
diff --git a/distrho/src/DistrhoPluginLV2export.cpp b/distrho/src/DistrhoPluginLV2export.cpp
index 13f37746..5423c6cb 100644
--- a/distrho/src/DistrhoPluginLV2export.cpp
+++ b/distrho/src/DistrhoPluginLV2export.cpp
@@ -804,11 +804,15 @@ void lv2_generate_ttl(const char* const basename)
                 bool isInput = false;
                 bool isOutput = false;
 
+#if DISTRHO_PLUGIN_NUM_INPUTS > 0
                 for (uint32_t i=0; i < DISTRHO_PLUGIN_NUM_INPUTS && !isInput; ++i)
                     isInput = plugin.getAudioPort(true, i).group == pgroupIndex;
+#endif
 
+#if DISTRHO_PLUGIN_NUM_OUTPUTS > 0
                 for (uint32_t i=0; i < DISTRHO_PLUGIN_NUM_OUTPUTS && !isOutput; ++i)
                     isOutput = plugin.getAudioPort(false, i).group == pgroupIndex;
+#endif
 
                 for (uint32_t i=0, count=plugin.getParameterCount(); i < count && (!isInput || !isOutput); ++i)
                 {