shader: Fix VertexA Shaders.

src/shader_recompiler/frontend/maxwell/program.cpp

@@ -171,20 +171,29 @@ IR::Program MergeDualVertexPrograms(IR::Program& vertex_a, IR::Program& vertex_b
     IR::Program result{};
     Optimization::VertexATransformPass(vertex_a);
     Optimization::VertexBTransformPass(vertex_b);
-    std::swap(result.blocks, vertex_a.blocks);
-    result.blocks.insert(result.blocks.end(), vertex_b.blocks.begin(), vertex_b.blocks.end());
+    for (const auto& term : vertex_a.syntax_list) {
+        if (term.type == IR::AbstractSyntaxNode::Type::Return) {
+            continue;
+        }
+        result.syntax_list.push_back(term);
+    }
+    for (const auto& term : vertex_b.syntax_list) {
+        result.syntax_list.push_back(term);
+    }
+    result.blocks = GenerateBlocks(result.syntax_list);
+    result.post_order_blocks = vertex_b.post_order_blocks;
+    for (const auto& block : vertex_a.post_order_blocks) {
+        result.post_order_blocks.push_back(block);
+    }
     result.stage = Stage::VertexB;
     result.info = vertex_a.info;
     result.local_memory_size = std::max(vertex_a.local_memory_size, vertex_b.local_memory_size);
-
     for (size_t index = 0; index < 32; ++index) {
         result.info.input_generics[index].used |= vertex_b.info.input_generics[index].used;
         result.info.stores_generics[index] |= vertex_b.info.stores_generics[index];
     }
     Optimization::JoinTextureInfo(result.info, vertex_b.info);
     Optimization::JoinStorageInfo(result.info, vertex_b.info);
-    Optimization::DualVertexJoinPass(result);
-    result.post_order_blocks = PostOrder(result.syntax_list.front());
     Optimization::DeadCodeEliminationPass(result);
     Optimization::VerificationPass(result);
     Optimization::CollectShaderInfoPass(env_vertex_b, result);

src/shader_recompiler/ir_opt/dual_vertex_pass.cpp

@@ -13,16 +13,24 @@
 
 namespace Shader::Optimization {
 
-void VertexATransformPass(IR::Program&) {
-    throw NotImplementedException("VertexA pass");
+void VertexATransformPass(IR::Program& program) {
+  for (IR::Block* const block : program.blocks) {
+      for (IR::Inst& inst : block->Instructions()) {
+          if (inst.GetOpcode() == IR::Opcode::Epilogue) {
+              return inst.Invalidate();
+          }
+      }
+  }
 }
 
-void VertexBTransformPass(IR::Program&) {
-    throw NotImplementedException("VertexA pass");
-}
-
-void DualVertexJoinPass(IR::Program&) {
-    throw NotImplementedException("VertexA pass");
+void VertexBTransformPass(IR::Program& program) {
+  for (IR::Block* const block : program.blocks) {
+      for (IR::Inst& inst : block->Instructions()) {
+          if (inst.GetOpcode() == IR::Opcode::Prologue) {
+              return inst.Invalidate();
+          }
+      }
+  }
 }
 
 } // namespace Shader::Optimization

src/shader_recompiler/ir_opt/passes.h

@@ -25,7 +25,6 @@ void VerificationPass(const IR::Program& program);
 // Dual Vertex
 void VertexATransformPass(IR::Program& program);
 void VertexBTransformPass(IR::Program& program);
-void DualVertexJoinPass(IR::Program& program);
 void JoinTextureInfo(Info& base, Info& source);
 void JoinStorageInfo(Info& base, Info& source);