Small fixes based on PR feedback

ScriptableRenderPipeline/HDRenderPipeline/Editor/HDRenderPipelineInspector.cs

             public readonly GUIContent renderingSettingsLabel = new GUIContent("Rendering Settings");
             public readonly GUIContent useForwardRenderingOnly = new GUIContent("Use Forward Rendering Only");
             public readonly GUIContent useDepthPrepassWithDeferredRendering = new GUIContent("Use Depth Prepass with Deferred rendering");
-            public readonly GUIContent useDepthPrepassWithDeferredRenderingAlphaTestOnly = new GUIContent("Alpha Test only");
+            public readonly GUIContent renderAlphaTestOnlyInDeferredPrepass = new GUIContent("Alpha Test only");
 
             // Texture Settings
             public readonly GUIContent textureSettings = new GUIContent("Texture Settings");
             // Rendering settings
             m_RenderingUseForwardOnly = FindProperty(x => x.renderingSettings.useForwardRenderingOnly);
             m_RenderingUseDepthPrepass = FindProperty(x => x.renderingSettings.useDepthPrepassWithDeferredRendering);
-            m_RenderingUseDepthPrepassAlphaTestOnly = FindProperty(x => x.renderingSettings.useDepthPrepassWithDeferredRenderingAlphaTestOnly);
+            m_RenderingUseDepthPrepassAlphaTestOnly = FindProperty(x => x.renderingSettings.renderAlphaTestOnlyInDeferredPrepass);
 
             // Subsurface Scattering Settings
             // Old SSS Model >>>
                 if(m_RenderingUseDepthPrepass.boolValue)
                 {
                     EditorGUI.indentLevel++;
-                    EditorGUILayout.PropertyField(m_RenderingUseDepthPrepassAlphaTestOnly, styles.useDepthPrepassWithDeferredRenderingAlphaTestOnly);
+                    EditorGUILayout.PropertyField(m_RenderingUseDepthPrepassAlphaTestOnly, styles.renderAlphaTestOnlyInDeferredPrepass);
                     EditorGUI.indentLevel--;
                 }
             }

ScriptableRenderPipeline/HDRenderPipeline/HDRenderPipeline.cs

     {
         public bool useForwardRenderingOnly = false; // TODO: Currently there is no way to strip the extra forward shaders generated by the shaders compiler, so we can switch dynamically.
         public bool useDepthPrepassWithDeferredRendering = false;
-        public bool useDepthPrepassWithDeferredRenderingAlphaTestOnly = false;
+        public bool renderAlphaTestOnlyInDeferredPrepass = false;
 
         // We have to fall back to forward-only rendering when scene view is using wireframe rendering mode --
         // as rendering everything in wireframe + deferred do not play well together
             // These need to be Runtime Only because those values are hold by the HDRenderPipeline asset so if user change them through the editor debug menu they might change the value in the asset without noticing it.
             DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Forward Only", () => (bool)m_Asset.renderingSettings.useForwardRenderingOnly, (value) => m_Asset.renderingSettings.useForwardRenderingOnly = (bool)value, DebugItemFlag.RuntimeOnly);
             DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Deferred Depth Prepass", () => (bool)m_Asset.renderingSettings.useDepthPrepassWithDeferredRendering, (value) => m_Asset.renderingSettings.useDepthPrepassWithDeferredRendering = (bool)value, DebugItemFlag.RuntimeOnly);
-            DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Deferred Depth Prepass ATest Only", () => (bool)m_Asset.renderingSettings.useDepthPrepassWithDeferredRenderingAlphaTestOnly, (value) => m_Asset.renderingSettings.useDepthPrepassWithDeferredRenderingAlphaTestOnly = (bool)value, DebugItemFlag.RuntimeOnly);
+            DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Deferred Depth Prepass ATest Only", () => (bool)m_Asset.renderingSettings.renderAlphaTestOnlyInDeferredPrepass, (value) => m_Asset.renderingSettings.renderAlphaTestOnlyInDeferredPrepass = (bool)value, DebugItemFlag.RuntimeOnly);
 
             DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Enable Tile/Cluster", () => (bool)m_Asset.tileSettings.enableTileAndCluster, (value) => m_Asset.tileSettings.enableTileAndCluster = (bool)value, DebugItemFlag.RuntimeOnly);
             DebugMenuManager.instance.AddDebugItem<bool>("HDRP", "Enable Big Tile", () => (bool)m_Asset.tileSettings.enableBigTilePrepass, (value) => m_Asset.tileSettings.enableBigTilePrepass = (bool)value, DebugItemFlag.RuntimeOnly);
             // Note that an object can't be in both list
             bool addForwardOnlyOpaqueDepthPrepass = !m_Asset.renderingSettings.ShouldUseForwardRenderingOnly() && !m_Asset.renderingSettings.useDepthPrepassWithDeferredRendering;
 
-            RenderQueueRange renderQueueRange = RenderQueueRange.opaque;
-            if (!m_Asset.renderingSettings.ShouldUseForwardRenderingOnly() && m_Asset.renderingSettings.useDepthPrepassWithDeferredRendering && m_Asset.renderingSettings.useDepthPrepassWithDeferredRenderingAlphaTestOnly)
-                renderQueueRange = new RenderQueueRange { min = (int)RenderQueue.AlphaTest, max = (int)RenderQueue.GeometryLast - 1 };
-
+                // Default depth prepass (forward and deferred) will render all opaque geometry.
+                RenderQueueRange renderQueueRange = RenderQueueRange.opaque;
+                // If we want only alpha tested geometry in prepass for deferred we change the RenderQueueRange
+                if (!m_Asset.renderingSettings.ShouldUseForwardRenderingOnly() && m_Asset.renderingSettings.useDepthPrepassWithDeferredRendering && m_Asset.renderingSettings.renderAlphaTestOnlyInDeferredPrepass)
+                    renderQueueRange = new RenderQueueRange { min = (int)RenderQueue.AlphaTest, max = (int)RenderQueue.GeometryLast - 1 };
+
                 // TODO: We should sort the Material by opaque then alpha masked Must do opaque then alpha masked for performance
                 Utilities.SetRenderTarget(cmd, m_CameraDepthStencilBufferRT);
                 // Note: addDepthPrepass and addForwardOnlyOpaqueDepthPrepass can't be both true at the same time. And if we are here both are not false
                         RenderQueueRange rangeOpaqueAlphaTest = new RenderQueueRange { min = (int)RenderQueue.AlphaTest, max = (int)RenderQueue.GeometryLast - 1 };
 
                         // When using depth prepass for alpha test only we need to use regular depth test for normal opaque objects.
-                        RenderOpaqueRenderList(cull, camera, renderContext, cmd, HDShaderPassNames.m_GBufferWithPrepassName, Utilities.kRendererConfigurationBakedLighting, rangeOpaqueNoAlphaTest, m_Asset.renderingSettings.useDepthPrepassWithDeferredRenderingAlphaTestOnly ? m_DepthStateOpaque : m_DepthStateOpaqueWithPrepass);
+                        RenderOpaqueRenderList(cull, camera, renderContext, cmd, HDShaderPassNames.m_GBufferWithPrepassName, Utilities.kRendererConfigurationBakedLighting, rangeOpaqueNoAlphaTest, m_Asset.renderingSettings.renderAlphaTestOnlyInDeferredPrepass ? m_DepthStateOpaque : m_DepthStateOpaqueWithPrepass);
                         RenderOpaqueRenderList(cull, camera, renderContext, cmd, HDShaderPassNames.m_GBufferWithPrepassName, Utilities.kRendererConfigurationBakedLighting, rangeOpaqueAlphaTest, m_DepthStateOpaqueWithPrepass);
                     }
                     else

ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLit.shader

             ENDHLSL
         }
 
-       Pass
+        // This pass is the same as GBuffer only it does not do alpha test (the clip instruction is removed)
+        // This is due to the fact that on GCN, any shader with a clip instruction cannot benefit from HiZ so when we do a prepass, in order to get the most performance, we need to make a special case in the subsequent GBuffer pass.
+        Pass
         {
             Name "GBufferWithPrepass"  // Name is not used
             Tags { "LightMode" = "GBufferWithPrepass" } // This will be only for opaque object based on the RenderQueue index

ScriptableRenderPipeline/HDRenderPipeline/Material/LayeredLit/LayeredLitTessellation.shader

             ENDHLSL
         }
 
+        // This pass is the same as GBuffer only it does not do alpha test (the clip instruction is removed)
+        // This is due to the fact that on GCN, any shader with a clip instruction cannot benefit from HiZ so when we do a prepass, in order to get the most performance, we need to make a special case in the subsequent GBuffer pass.
         Pass
         {
             Name "GBufferWithPrepass"  // Name is not used

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Lit.shader

             ENDHLSL
         }
 
+        // This pass is the same as GBuffer only it does not do alpha test (the clip instruction is removed)
+        // This is due to the fact that on GCN, any shader with a clip instruction cannot benefit from HiZ so when we do a prepass, in order to get the most performance, we need to make a special case in the subsequent GBuffer pass.
         Pass
         {
             Name "GBufferWithPrepass"  // Name is not used

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitTessellation.shader

             ENDHLSL
         }
 
+        // This pass is the same as GBuffer only it does not do alpha test (the clip instruction is removed)
+        // This is due to the fact that on GCN, any shader with a clip instruction cannot benefit from HiZ so when we do a prepass, in order to get the most performance, we need to make a special case in the subsequent GBuffer pass.
         Pass
         {
             Name "GBufferWithPrepass"  // Name is not used