1 files changed, 38 insertions, 0 deletions

diff --git a/src/shader_recompiler/ir_opt/identity_removal_pass.cpp b/src/shader_recompiler/ir_opt/identity_removal_pass.cpp
new file mode 100644
index 000000000..e9b55f835
--- /dev/null
+++ b/src/shader_recompiler/ir_opt/identity_removal_pass.cpp
@@ -0,0 +1,38 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <vector>
+
+#include "shader_recompiler/frontend/ir/basic_block.h"
+#include "shader_recompiler/frontend/ir/value.h"
+#include "shader_recompiler/ir_opt/passes.h"
+
+namespace Shader::Optimization {
+
+void IdentityRemovalPass(IR::Program& program) {
+    std::vector<IR::Inst*> to_invalidate;
+    for (IR::Block* const block : program.blocks) {
+        for (auto inst = block->begin(); inst != block->end();) {
+            const size_t num_args{inst->NumArgs()};
+            for (size_t i = 0; i < num_args; ++i) {
+                IR::Value arg;
+                while ((arg = inst->Arg(i)).IsIdentity()) {
+                    inst->SetArg(i, arg.Inst()->Arg(0));
+                }
+            }
+            if (inst->GetOpcode() == IR::Opcode::Identity ||
+                inst->GetOpcode() == IR::Opcode::Void) {
+                to_invalidate.push_back(&*inst);
+                inst = block->Instructions().erase(inst);
+            } else {
+                ++inst;
+            }
+        }
+    }
+    for (IR::Inst* const inst : to_invalidate) {
+        inst->Invalidate();
+    }
+}
+
+} // namespace Shader::Optimization