diff --git a/modules/juce_audio_basics/buffers/juce_AudioSampleBuffer.h b/modules/juce_audio_basics/buffers/juce_AudioSampleBuffer.h
index ddd5889673..5fbad7aac5 100644
--- a/modules/juce_audio_basics/buffers/juce_AudioSampleBuffer.h
+++ b/modules/juce_audio_basics/buffers/juce_AudioSampleBuffer.h
@@ -569,17 +569,17 @@ public:
     */
     void clear() noexcept
     {
-        if (! isClear)
-        {
-            for (int i = 0; i < numChannels; ++i)
-            {
-                JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4661)
-                FloatVectorOperations::clear (channels[i], size);
-                JUCE_END_IGNORE_WARNINGS_MSVC
-            }
+        if (isClear)
+            return;
 
-            isClear = true;
+        for (int i = 0; i < numChannels; ++i)
+        {
+            JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4661)
+            FloatVectorOperations::clear (channels[i], size);
+            JUCE_END_IGNORE_WARNINGS_MSVC
         }
+
+        isClear = true;
     }
 
     /** Clears a specified region of all the channels.
@@ -598,13 +598,13 @@ public:
     {
         jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
 
-        if (! isClear)
-        {
-            for (int i = 0; i < numChannels; ++i)
-                FloatVectorOperations::clear (channels[i] + startSample, numSamples);
+        if (isClear)
+            return;
 
-            isClear = (startSample == 0 && numSamples == size);
-        }
+        for (int i = 0; i < numChannels; ++i)
+            FloatVectorOperations::clear (channels[i] + startSample, numSamples);
+
+        isClear = (startSample == 0 && numSamples == size);
     }
 
     /** Clears a specified region of just one channel.
@@ -700,11 +700,11 @@ public:
         jassert (isPositiveAndBelow (channel, numChannels));
         jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
 
-        if (! isClear)
-        {
-            auto* d = channels[channel] + startSample;
-            FloatVectorOperations::multiply (d, gain, numSamples);
-        }
+        if (isClear)
+            return;
+
+        auto* d = channels[channel] + startSample;
+        FloatVectorOperations::multiply (d, gain, numSamples);
     }
 
     /** Applies a gain multiple to a region of all the channels.
@@ -736,19 +736,19 @@ public:
     void applyGainRamp (int channel, int startSample, int numSamples,
                         Type startGain, Type endGain) noexcept
     {
-        if (! isClear)
+        jassert (isPositiveAndBelow (channel, numChannels));
+        jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
+
+        if (isClear)
+            return;
+
+        const auto increment = (endGain - startGain) / (float) numSamples;
+        auto* d = channels[channel] + startSample;
+
+        while (--numSamples >= 0)
         {
-            jassert (isPositiveAndBelow (channel, numChannels));
-            jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
-
-            const auto increment = (endGain - startGain) / (float) numSamples;
-            auto* d = channels[channel] + startSample;
-
-            while (--numSamples >= 0)
-            {
-                *d++ *= startGain;
-                startGain += increment;
-            }
+            *d++ *= startGain;
+            startGain += increment;
         }
     }
 
@@ -801,25 +801,25 @@ public:
         jassert (isPositiveAndBelow (sourceChannel, source.numChannels));
         jassert (sourceStartSample >= 0 && sourceStartSample + numSamples <= source.size);
 
-        if (numSamples > 0 && ! source.isClear)
+        if (numSamples <= 0 || source.isClear)
+            return;
+
+        auto* d = channels[destChannel] + destStartSample;
+        auto* s = source.channels[sourceChannel] + sourceStartSample;
+
+        JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4661)
+
+        if (isClear)
         {
-            auto* d = channels[destChannel] + destStartSample;
-            auto* s = source.channels[sourceChannel] + sourceStartSample;
-
-            JUCE_BEGIN_IGNORE_WARNINGS_MSVC (4661)
-
-            if (isClear)
-            {
-                isClear = false;
-                FloatVectorOperations::copyWithMultiply (d, s, gainToApplyToSource, numSamples);
-            }
-            else
-            {
-                FloatVectorOperations::addWithMultiply (d, s, gainToApplyToSource, numSamples);
-            }
-
-            JUCE_END_IGNORE_WARNINGS_MSVC
+            isClear = false;
+            FloatVectorOperations::copyWithMultiply (d, s, gainToApplyToSource, numSamples);
         }
+        else
+        {
+            FloatVectorOperations::addWithMultiply (d, s, gainToApplyToSource, numSamples);
+        }
+
+        JUCE_END_IGNORE_WARNINGS_MSVC
     }
 
     /** Adds samples from an array of floats to one of the channels.
@@ -846,6 +846,9 @@ public:
         jassert (destStartSample >= 0 && numSamples >= 0 && destStartSample + numSamples <= size);
         jassert (source != nullptr);
 
+        if (numSamples <= 0)
+            return;
+
         auto* d = channels[destChannel] + destStartSample;
 
         if (isClear)
@@ -889,19 +892,19 @@ public:
         jassert (destStartSample >= 0 && numSamples >= 0 && destStartSample + numSamples <= size);
         jassert (source != nullptr);
 
-        if (numSamples > 0)
-        {
-            isClear = false;
-            const auto increment = (endGain - startGain) / (Type) numSamples;
-            auto* d = channels[destChannel] + destStartSample;
+        if (numSamples <= 0)
+            return;
 
-            while (--numSamples >= 0)
-            {
-                *d++ += startGain * *source++;
-                startGain += increment;
-            }
+        isClear = false;
+        const auto increment = (endGain - startGain) / (Type) numSamples;
+        auto* d = channels[destChannel] + destStartSample;
+
+        while (--numSamples >= 0)
+        {
+            *d++ += startGain * *source++;
+            startGain += increment;
         }
-    }
+}
 
     /** Copies samples from another buffer to this one.
 
@@ -930,20 +933,20 @@ public:
         jassert (isPositiveAndBelow (sourceChannel, source.numChannels));
         jassert (sourceStartSample >= 0 && numSamples >= 0 && sourceStartSample + numSamples <= source.size);
 
-        if (numSamples > 0)
+        if (numSamples <= 0)
+            return;
+
+        if (source.isClear)
         {
-            if (source.isClear)
-            {
-                if (! isClear)
-                    FloatVectorOperations::clear (channels[destChannel] + destStartSample, numSamples);
-            }
-            else
-            {
-                isClear = false;
-                FloatVectorOperations::copy (channels[destChannel] + destStartSample,
-                                             source.channels[sourceChannel] + sourceStartSample,
-                                             numSamples);
-            }
+            if (! isClear)
+                FloatVectorOperations::clear (channels[destChannel] + destStartSample, numSamples);
+        }
+        else
+        {
+            isClear = false;
+            FloatVectorOperations::copy (channels[destChannel] + destStartSample,
+                                         source.channels[sourceChannel] + sourceStartSample,
+                                         numSamples);
         }
     }
 
@@ -968,11 +971,11 @@ public:
         jassert (destStartSample >= 0 && numSamples >= 0 && destStartSample + numSamples <= size);
         jassert (source != nullptr);
 
-        if (numSamples > 0)
-        {
-            isClear = false;
-            FloatVectorOperations::copy (channels[destChannel] + destStartSample, source, numSamples);
-        }
+        if (numSamples <= 0)
+            return;
+
+        isClear = false;
+        FloatVectorOperations::copy (channels[destChannel] + destStartSample, source, numSamples);
     }
 
     /** Copies samples from an array of floats into one of the channels, applying a gain to it.
@@ -998,12 +1001,12 @@ public:
         jassert (destStartSample >= 0 && numSamples >= 0 && destStartSample + numSamples <= size);
         jassert (source != nullptr);
 
-        if (numSamples > 0)
-        {
-            auto* d = channels[destChannel] + destStartSample;
-            isClear = false;
-            FloatVectorOperations::copyWithMultiply (d, source, gain, numSamples);
-        }
+        if (numSamples <= 0)
+            return;
+
+        auto* d = channels[destChannel] + destStartSample;
+        isClear = false;
+        FloatVectorOperations::copyWithMultiply (d, source, gain, numSamples);
     }
 
     /** Copies samples from an array of floats into one of the channels, applying a gain ramp.
@@ -1037,17 +1040,17 @@ public:
         jassert (destStartSample >= 0 && numSamples >= 0 && destStartSample + numSamples <= size);
         jassert (source != nullptr);
 
-        if (numSamples > 0)
-        {
-            isClear = false;
-            const auto increment = (endGain - startGain) / (Type) numSamples;
-            auto* d = channels[destChannel] + destStartSample;
+        if (numSamples <= 0)
+            return;
 
-            while (--numSamples >= 0)
-            {
-                *d++ = startGain * *source++;
-                startGain += increment;
-            }
+        isClear = false;
+        const auto increment = (endGain - startGain) / (Type) numSamples;
+        auto* d = channels[destChannel] + destStartSample;
+
+        while (--numSamples >= 0)
+        {
+            *d++ = startGain * *source++;
+            startGain += increment;
         }
     }
 
@@ -1077,8 +1080,7 @@ public:
         if (isClear)
             return Type (0);
 
-        auto r = findMinMax (channel, startSample, numSamples);
-
+        const auto r = findMinMax (channel, startSample, numSamples);
         return jmax (r.getStart(), -r.getStart(), r.getEnd(), -r.getEnd());
     }
 
@@ -1087,9 +1089,11 @@ public:
     {
         Type mag (0);
 
-        if (! isClear)
-            for (int i = 0; i < numChannels; ++i)
-                mag = jmax (mag, getMagnitude (i, startSample, numSamples));
+        if (isClear)
+            return mag;
+
+        for (int i = 0; i < numChannels; ++i)
+            mag = jmax (mag, getMagnitude (i, startSample, numSamples));
 
         return mag;
     }
@@ -1100,7 +1104,7 @@ public:
         jassert (isPositiveAndBelow (channel, numChannels));
         jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
 
-        if (numSamples <= 0 || channel < 0 || channel >= numChannels || isClear)
+        if (numSamples <= 0 || isClear || ! isPositiveAndBelow (channel, numChannels))
             return Type (0);
 
         auto* data = channels[channel] + startSample;
@@ -1121,14 +1125,21 @@ public:
         jassert (isPositiveAndBelow (channel, numChannels));
         jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
 
-        if (! isClear)
-            std::reverse (channels[channel] + startSample,
-                          channels[channel] + startSample + numSamples);
+        if (isClear)
+            return;
+
+        std::reverse (channels[channel] + startSample,
+                      channels[channel] + startSample + numSamples);
     }
 
     /** Reverses a part of the buffer. */
     void reverse (int startSample, int numSamples) const noexcept
     {
+        jassert (startSample >= 0 && numSamples >= 0 && startSample + numSamples <= size);
+
+        if (isClear)
+            return;
+
         for (int i = 0; i < numChannels; ++i)
             reverse (i, startSample, numSamples);
     }