Fix glm4-9b-chat nan error on vllm 0.3.3 (#11970)

* fix nan value

* update

python/llm/src/ipex_llm/vllm/xpu/model_convert.py

@@ -248,7 +248,15 @@ def _ipex_llm_load_model(self) -> None:
                                    parallel_config=self.parallel_config,
                                    scheduler_config=self.scheduler_config)
             from ipex_llm import optimize_model
-            optimize_model(self.model, low_bit=low_bit, torch_dtype=self.model_config.dtype)
+            import os
+            not_convert_last_mlp = os.getenv("IPEX_LLM_NOT_CONVERT_LAST_MLP", None)
+            if not_convert_last_mlp is not None:
+                # only use to avoid nan value in last mlp forward running glm4-9b-chat
+                modules = ["35.mlp", "36.mlp", "37.mlp", "38.mlp", "39.mlp"]
+            else:
+                modules = None
+            optimize_model(self.model, low_bit=low_bit, torch_dtype=self.model_config.dtype,
+                           modules_to_not_convert=modules)
             self.model = self.model.to(device=self.device_config.device,
                                        dtype=self.model_config.dtype)