2 files changed, 58 insertions, 34 deletions

diff --git a/src/video_core/shader/shader_ir.cpp b/src/video_core/shader/shader_ir.cpp
index 32bb28452..baf7188d2 100644
--- a/src/video_core/shader/shader_ir.cpp
+++ b/src/video_core/shader/shader_ir.cpp
@@ -96,6 +96,7 @@ Node ShaderIR::GetPredicate(bool immediate) {
 }
 
 Node ShaderIR::GetInputAttribute(Attribute::Index index, u64 element, Node buffer) {
+    MarkAttributeUsage(index, element);
     used_input_attributes.emplace(index);
     return MakeNode<AbufNode>(index, static_cast<u32>(element), std::move(buffer));
 }
@@ -106,40 +107,7 @@ Node ShaderIR::GetPhysicalInputAttribute(Tegra::Shader::Register physical_addres
 }
 
 Node ShaderIR::GetOutputAttribute(Attribute::Index index, u64 element, Node buffer) {
-    switch (index) {
-    case Attribute::Index::LayerViewportPointSize:
-        switch (element) {
-        case 0:
-            UNIMPLEMENTED();
-            break;
-        case 1:
-            uses_layer = true;
-            break;
-        case 2:
-            uses_viewport_index = true;
-            break;
-        case 3:
-            uses_point_size = true;
-            break;
-        }
-        break;
-    case Attribute::Index::TessCoordInstanceIDVertexID:
-        switch (element) {
-        case 2:
-            uses_instance_id = true;
-            break;
-        case 3:
-            uses_vertex_id = true;
-            break;
-        }
-        break;
-    case Attribute::Index::ClipDistances0123:
-    case Attribute::Index::ClipDistances4567: {
-        const u64 clip_index = (index == Attribute::Index::ClipDistances4567 ? 4 : 0) + element;
-        used_clip_distances.at(clip_index) = true;
-        break;
-    }
-    }
+    MarkAttributeUsage(index, element);
     used_output_attributes.insert(index);
     return MakeNode<AbufNode>(index, static_cast<u32>(element), std::move(buffer));
 }
@@ -451,6 +419,54 @@ Node ShaderIR::BitfieldInsert(Node base, Node insert, u32 offset, u32 bits) {
                      Immediate(bits));
 }
 
+void ShaderIR::MarkAttributeUsage(Attribute::Index index, u64 element) {
+    switch (index) {
+    case Attribute::Index::LayerViewportPointSize:
+        switch (element) {
+        case 0:
+            UNIMPLEMENTED();
+            break;
+        case 1:
+            uses_layer = true;
+            break;
+        case 2:
+            uses_viewport_index = true;
+            break;
+        case 3:
+            uses_point_size = true;
+            break;
+        }
+        break;
+    case Attribute::Index::TessCoordInstanceIDVertexID:
+        switch (element) {
+        case 2:
+            uses_instance_id = true;
+            break;
+        case 3:
+            uses_vertex_id = true;
+            break;
+        }
+        break;
+    case Attribute::Index::ClipDistances0123:
+    case Attribute::Index::ClipDistances4567: {
+        const u64 clip_index = (index == Attribute::Index::ClipDistances4567 ? 4 : 0) + element;
+        used_clip_distances.at(clip_index) = true;
+        break;
+    }
+    case Attribute::Index::FrontColor:
+    case Attribute::Index::FrontSecondaryColor:
+    case Attribute::Index::BackColor:
+    case Attribute::Index::BackSecondaryColor:
+        uses_legacy_varyings = true;
+        break;
+    default:
+        if (index >= Attribute::Index::TexCoord_0 && index <= Attribute::Index::TexCoord_7) {
+            uses_legacy_varyings = true;
+        }
+        break;
+    }
+}
+
 std::size_t ShaderIR::DeclareAmend(Node new_amend) {
     const std::size_t id = amend_code.size();
     amend_code.push_back(new_amend);
diff --git a/src/video_core/shader/shader_ir.h b/src/video_core/shader/shader_ir.h
index dde036b40..80fc9b82c 100644
--- a/src/video_core/shader/shader_ir.h
+++ b/src/video_core/shader/shader_ir.h
@@ -137,6 +137,10 @@ public:
         return uses_vertex_id;
     }
 
+    bool UsesLegacyVaryings() const {
+        return uses_legacy_varyings;
+    }
+
     bool UsesWarps() const {
         return uses_warps;
     }
@@ -343,6 +347,9 @@ private:
     /// Inserts a sequence of bits from a node
     Node BitfieldInsert(Node base, Node insert, u32 offset, u32 bits);
 
+    /// Marks the usage of a input or output attribute.
+    void MarkAttributeUsage(Tegra::Shader::Attribute::Index index, u64 element);
+
     void WriteTexInstructionFloat(NodeBlock& bb, Tegra::Shader::Instruction instr,
                                   const Node4& components);
 
@@ -443,6 +450,7 @@ private:
     bool uses_physical_attributes{}; // Shader uses AL2P or physical attribute read/writes
     bool uses_instance_id{};
     bool uses_vertex_id{};
+    bool uses_legacy_varyings{};
     bool uses_warps{};
     bool uses_indexed_samplers{};