1 files changed, 87 insertions, 0 deletions
diff --git a/src/shader_recompiler/ir_opt/get_set_elimination_pass.cpp b/src/shader_recompiler/ir_opt/get_set_elimination_pass.cpp
new file mode 100644
index 000000000..21b8526cd
--- /dev/null
+++ b/src/shader_recompiler/ir_opt/get_set_elimination_pass.cpp
@@ -0,0 +1,87 @@
+// Copyright 2021 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <array>
+
+#include "shader_recompiler/frontend/ir/basic_block.h"
+#include "shader_recompiler/frontend/ir/microinstruction.h"
+#include "shader_recompiler/ir_opt/passes.h"
+
+namespace Shader::Optimization {
+namespace {
+using Iterator = IR::Block::iterator;
+
+enum class TrackingType {
+    Reg,
+};
+
+struct RegisterInfo {
+    IR::Value register_value;
+    TrackingType tracking_type;
+    Iterator last_set_instruction;
+    bool set_instruction_present = false;
+};
+
+void DoSet(IR::Block& block, RegisterInfo& info, IR::Value value, Iterator set_inst,
+           TrackingType tracking_type) {
+    if (info.set_instruction_present) {
+        info.last_set_instruction->Invalidate();
+        block.Instructions().erase(info.last_set_instruction);
+    }
+    info.register_value = value;
+    info.tracking_type = tracking_type;
+    info.set_instruction_present = true;
+    info.last_set_instruction = set_inst;
+}
+
+RegisterInfo Nothing(Iterator get_inst, TrackingType tracking_type) {
+    RegisterInfo info{};
+    info.register_value = IR::Value{&*get_inst};
+    info.tracking_type = tracking_type;
+    return info;
+}
+
+void DoGet(RegisterInfo& info, Iterator get_inst, TrackingType tracking_type) {
+    if (info.register_value.IsEmpty()) {
+        info = Nothing(get_inst, tracking_type);
+        return;
+    }
+    if (info.tracking_type == tracking_type) {
+        get_inst->ReplaceUsesWith(info.register_value);
+        return;
+    }
+    info = Nothing(get_inst, tracking_type);
+}
+} // Anonymous namespace
+
+void GetSetElimination(IR::Block& block) {
+    std::array<RegisterInfo, 255> reg_info;
+
+    for (Iterator inst = block.begin(); inst != block.end(); ++inst) {
+        switch (inst->Opcode()) {
+        case IR::Opcode::GetRegister: {
+            const IR::Reg reg{inst->Arg(0).Reg()};
+            if (reg == IR::Reg::RZ) {
+                break;
+            }
+            const size_t index{static_cast<size_t>(reg)};
+            DoGet(reg_info.at(index), inst, TrackingType::Reg);
+            break;
+        }
+        case IR::Opcode::SetRegister: {
+            const IR::Reg reg{inst->Arg(0).Reg()};
+            if (reg == IR::Reg::RZ) {
+                break;
+            }
+            const size_t index{static_cast<size_t>(reg)};
+            DoSet(block, reg_info.at(index), inst->Arg(1), inst, TrackingType::Reg);
+            break;
+        }
+        default:
+            break;
+        }
+    }
+}
+
+} // namespace Shader::Optimization