feat: 条件表达式支持类型提升

src/main/java/org/jcnc/snow/compiler/backend/generator/CmpJumpGenerator.java

@@ -28,6 +28,60 @@ public class CmpJumpGenerator implements InstructionGenerator<IRCompareJumpInstr
         return IRCompareJumpInstruction.class;
     }
 
+    /**
+     * 类型优先级：D &gt; F &gt; L &gt; I &gt; S &gt; B
+     */
+    private static int rank(char p) {
+        return switch (p) {
+            case 'D' -> 6;
+            case 'F' -> 5;
+            case 'L' -> 4;
+            case 'I' -> 3;
+            case 'S' -> 2;
+            case 'B' -> 1;
+            default -> 0;
+        };
+    }
+
+    /**
+     * 返回优先级更高的类型字符
+     */
+    private static char promote(char a, char b) {
+        return rank(a) >= rank(b) ? a : b;
+    }
+
+    /**
+     * 单字符转字符串
+     */
+    private static String str(char p) {
+        return String.valueOf(p);
+    }
+
+    /**
+     * 获取从类型 {@code from} 到 {@code to} 的转换指令名。
+     * 相同类型或无显式转换需求返回 {@code null}。
+     */
+    private static String convert(char from, char to) {
+        if (from == to) return null;
+        return switch ("" + from + to) {
+            case "IL" -> "I2L";
+            case "ID" -> "I2D";
+            case "IF" -> "I2F";
+            case "LI" -> "L2I";
+            case "LD" -> "L2D";
+            case "LF" -> "L2F";
+            case "FI" -> "F2I";
+            case "FL" -> "F2L";
+            case "FD" -> "F2D";
+            case "DI" -> "D2I";
+            case "DL" -> "D2L";
+            case "DF" -> "D2F";
+            case "SI" -> "S2I";
+            case "BI" -> "B2I";
+            default -> null;
+        };
+    }
+
     /**
      * 生成条件比较跳转相关的虚拟机指令。
      *
@@ -45,10 +99,22 @@ public class CmpJumpGenerator implements InstructionGenerator<IRCompareJumpInstr
         int leftSlot = slotMap.get(ins.left());
         // 获取右操作数所在的寄存器槽编号
         int rightSlot = slotMap.get(ins.right());
+
+        char lType = out.getSlotType(leftSlot); // 未登记默认 'I'
+        char rType = out.getSlotType(rightSlot);
+
+        char tType = promote(lType, rType); // 类型提升结果
+
         // 加载左操作数到虚拟机栈
-        out.emit(OpHelper.opcode("L_LOAD") + " " + leftSlot);
+        out.emit(OpHelper.opcode(str(lType) + "_LOAD") + " " + leftSlot);
+        String cvt = convert(lType, tType);
+        if (cvt != null) out.emit(OpHelper.opcode(cvt));
+
         // 加载右操作数到虚拟机栈
-        out.emit(OpHelper.opcode("L_LOAD") + " " + rightSlot);
+        out.emit(OpHelper.opcode(str(rType) + "_LOAD") + " " + rightSlot);
+        cvt = convert(rType, tType);
+        if (cvt != null) out.emit(OpHelper.opcode(cvt));
+
         // 获取与当前比较操作对应的虚拟机操作码
         String cmpOp = IROpCodeMapper.toVMOp(ins.op());
         // 生成分支跳转指令，如果比较成立则跳转到目标标签