From 360d7a7ccd1bf5a619c194ec2e7931b6afa56be5 Mon Sep 17 00:00:00 2001
From: SimoneN64 <simococo03@gmail.com>
Date: Mon, 25 Dec 2023 21:59:47 +0100
Subject: [PATCH] first optimization

---
 src/backend/core/JIT.cpp    |  1 +
 src/backend/core/JIT/IR.cpp | 43 +++++++++++++++++++++++++++++++++----
 src/backend/core/JIT/IR.hpp | 12 ++++++++++-
 3 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/src/backend/core/JIT.cpp b/src/backend/core/JIT.cpp
index 767755b1..9fe222db 100644
--- a/src/backend/core/JIT.cpp
+++ b/src/backend/core/JIT.cpp
@@ -81,6 +81,7 @@ _epilogue:
   //ready();
   //return getCode<Fn>();
   ir.optimize();
+  ir.print();
   exit(1);
   return nullptr;
 }
diff --git a/src/backend/core/JIT/IR.cpp b/src/backend/core/JIT/IR.cpp
index 3cf75e60..f383f696 100644
--- a/src/backend/core/JIT/IR.cpp
+++ b/src/backend/core/JIT/IR.cpp
@@ -151,18 +151,20 @@ template <> struct fmt::formatter<Entry> : formatter<string_view> {
         std::string op1 = fmt::format("R{}", e.op1.index_or_imm.value());
         if(put_comma) {
           op += ", ";
+        } else {
+          put_comma = true;
         }
         op += op1;
-        put_comma = true;
       }
     } else {
       if (e.op1.index_or_imm.has_value()) {
         std::string op1 = fmt::format("0x{:0X}", e.op1.index_or_imm.value());
         if(put_comma) {
           op += ", ";
+        } else {
+          put_comma = true;
         }
         op += op1;
-        put_comma = true;
       }
     }
 
@@ -171,18 +173,20 @@ template <> struct fmt::formatter<Entry> : formatter<string_view> {
         std::string op2 = fmt::format("R{}", e.op2.index_or_imm.value());
         if(put_comma) {
           op += ", ";
+        } else {
+          put_comma = true;
         }
         op += op2;
-        put_comma = true;
       }
     } else {
       if (e.op2.index_or_imm.has_value()) {
         std::string op2 = fmt::format("0x{:0X}", e.op2.index_or_imm.value());
         if(put_comma) {
           op += ", ";
+        } else {
+          put_comma = true;
         }
         op += op2;
-        put_comma = true;
       }
     }
 
@@ -211,6 +215,37 @@ void IR::push(const Entry& e) {
 }
 
 void IR::optimize() {
+  std::vector<Entry> optimized{};
+
+  for(const auto& i : code) {
+    bool isOp1Reg = i.op1.isReg();
+    bool isOp2Reg = i.op2.isReg();
+    bool isDstReg = i.dst.isReg();
+
+    if(isDstReg) {
+      if(isOp1Reg) {
+        if(i.op1.index_or_imm == i.dst.index_or_imm
+          && i.zeroRendersItUseless()) continue;
+      }
+
+      if(isOp2Reg) {
+        if(i.op2.index_or_imm == i.dst.index_or_imm
+           && i.zeroRendersItUseless()) continue;
+      }
+    }
+
+    optimized.push_back(i);
+  }
+
+  if(optimized.size() == code.size()) {
+    return;
+  }
+
+  code = optimized;
+  optimize();
+}
+
+void IR::print() {
   for(auto e : code) {
     fmt::print("{}", e);
   }
diff --git a/src/backend/core/JIT/IR.hpp b/src/backend/core/JIT/IR.hpp
index b75f7eb8..77b4ff0f 100644
--- a/src/backend/core/JIT/IR.hpp
+++ b/src/backend/core/JIT/IR.hpp
@@ -38,11 +38,16 @@ struct Entry {
       LO, HI
 		} type = NONE;
 
-    bool isReg() {
+    bool isReg() const {
       return type == REG_S64 || type == REG_F32 || type == REG_F64 || type == REG_S32
               || type == REG_U64 || type == REG_U32 || type == REG_U5;
     }
 
+    bool isImm() const {
+      return type == IMM_S64 || type == IMM_F32 || type == IMM_F64 || type == IMM_S32
+             || type == IMM_U64 || type == IMM_U32 || type == IMM_U5;
+    }
+
 		std::optional<u64> index_or_imm = std::nullopt;
 
     Operand() = default;
@@ -50,6 +55,10 @@ struct Entry {
 			: type(t), index_or_imm(imm) {}
 	} dst, op1, op2;
 
+  bool zeroRendersItUseless() const {
+    return op == ADD || op == OR || op == SRL || op == SLL || op == SRA;
+  }
+
   [[nodiscard]] const Operand& GetDst() const { return dst; }
 
 	enum BranchCond {
@@ -71,6 +80,7 @@ struct IR {
 	void push(const Entry&);
 	auto begin();
 	auto end();
+  void print();
   void optimize();
 private:
 	std::vector<Entry> code{};