[optimize]添加更为通用的除法强度削减Pass, 不受除数限制替换div指令，不影响当前分数

src/midend/SysYIRGenerator.cpp

@@ -15,6 +15,29 @@
 using namespace std;
 namespace sysy {
 
+std::pair<long long, int> calculate_signed_magic(int d) {
+    if (d == 0) throw std::runtime_error("Division by zero");
+    if (d == 1 || d == -1) return {0, 0}; // Not used by strength reduction
+
+    int k = 0;
+    unsigned int ad = (d > 0) ? d : -d;
+    unsigned int temp = ad;
+    while (temp > 0) {
+        temp >>= 1;
+        k++;
+    }
+    if ((ad & (ad - 1)) == 0) { // if power of 2
+        k--;
+    }
+
+    unsigned __int128 m_val = 1;
+    m_val <<= (32 + k - 1);
+    unsigned __int128 m_prime = m_val / ad;
+    long long m = m_prime + 1;
+
+    return {m, k};
+}
+
 
 // std::vector<Value*> BinaryValueStack;  ///< 用于存储value的栈
 // std::vector<int> BinaryOpStack;  ///< 用于存储二元表达式的操作符栈