diff --git a/includes/llvmlite/__builder.vp b/includes/llvmlite/__builder.vp
index 1b3737d..0de1afc 100644
--- a/includes/llvmlite/__builder.vp
+++ b/includes/llvmlite/__builder.vp
@@ -4,6 +4,7 @@ import string
 import viperlib
 import memhub
 import stdio
+import stdlib
 from linkedlist import GSListNode, GSList
 from .__types import LLVMType, TypePrint
 from .__values import Value, new_value, SSAValue
@@ -58,6 +59,19 @@ class IRBuilder:
         if buf is None: return None
         buf[0] = '\0'
         TypePrint(buf, 512, ty, pool)
+        # [IR-FAIL] 校验护栏：LLVMType 类型对象可能被 MemBuddy 覆盖/悬空
+        # （跨遍 reset 回收后 pool 内存复用），此时 TypePrint 输出首字符
+        # 变为垃圾（如 't'）或为空。立即 fail-fast 终止，防止生成
+        # `bitcast i8* null t` 类垃圾 IR，避免 llc 报 "expected 'to' after
+        # cast value" 后难以定位根因。
+        c0: t.CInt = buf[0]
+        if c0 == 0 or (c0 != '%' and c0 != '[' and c0 != '{' and c0 != 'f' and
+                       c0 != 'd' and c0 != 'h' and c0 != 'i' and c0 != 'l' and
+                       c0 != 'm' and c0 != 'v' and c0 != '.'):
+            stdio.printf("[IR-FAIL] _type_str: LLVMType 对象已损坏 ty=0x%llx 首字符=%d 输出='%s'\n",
+                         t.CUInt64T(ty), c0, buf)
+            stdlib.exit(1)
+            return None
         return buf