feat(aot): 改进switch语句编译逻辑支持默认分支

- 添加了default分支的特殊处理逻辑
- 实现了defaultOnly标识用于优化条件判断
- 修正了switch case条件列表的构建方式
- 添加了对多个测试用例的支持验证
- 优化了分支条件的代码生成策略
- 确保了break语句后的正确流程控制

src/Php/CompilerBase.php

@@ -3398,11 +3398,11 @@ class CompilerBase extends \PhpAot\Core\Translator
         $code = 'do {' . PHP_EOL;
         $this->indentLevel++;
         $condList = [];
+        $defaultCase = false;
+        $defaultOnly = true;
         foreach ($v->cases as $case) {
             if (empty($case->cond)) {
-                if ($condList) {
+                $defaultCase = true;
-                    $this->fatalError($case, 'switch case must be first');
-                }
             } else {
                 $condList[] = $tmp_var . '==' . $this->parseIdentifier($case->cond);
             }
@@ -3423,11 +3423,13 @@ class CompilerBase extends \PhpAot\Core\Translator
                 $this->fatalError($case, 'switch case must end with return/break/exit/throw, ' . $lastExpr->getType() . ' given');
             }
 
-            if ($condList) {
+            if ($defaultCase) {
+                $else = $defaultOnly ? '' : 'else';
+                $code .= $this->getIndent() . $else . ' {' . PHP_EOL;
+            } else {
                 $code .= $this->getIndent() . 'if (' . implode(' || ', $condList) . ') {' . PHP_EOL;
+                $defaultOnly = false;
                 $condList = [];
-            } else {
-                $code .= $this->getIndent() . 'else {' . PHP_EOL;
             }
 
             $code .= $this->parseStmts($stmts);

tests/aot/switch/003.phpt

@@ -0,0 +1,18 @@
+--TEST--
+switch
+--FILE--
+<?php
+function main()
+{
+    $c = 100;
+    switch ($c) {
+    case 100:
+    case 99:
+    default:
+        echo "default\n";
+        break;
+    }
+}
+?>
+--EXPECT--
+default

tests/aot/switch/004.phpt

@@ -0,0 +1,27 @@
+--TEST--
+switch
+--FILE--
+<?php
+function foo($c)
+{
+    switch ($c) {
+    case 1:
+    case 2:
+        echo "case 1\n";
+        break;
+    case 100:
+    case 99:
+    default:
+        echo "default\n";
+        break;
+    }
+}
+
+function main() {
+    foo(1);
+    foo(100);
+}
+?>
+--EXPECT--
+case 1
+default