[XPU] disable fusion pattern support on XPU platform (#39789)

Signed-off-by: Chaojun Zhang <chaojun.zhang@intel.com>
Co-authored-by: Kunshang Ji <kunshang.ji@intel.com>

vllm/platforms/xpu.py

@@ -213,6 +213,26 @@ class XPUPlatform(Platform):
                     "falling back to PIECEWISE graph mode on XPU platform."
                 )
 
+        # Disable fusion passes not yet supported on XPU.
+        pass_config = compilation_config.pass_config
+        fusion_passes_to_disable = {
+            "enable_sp": "Sequence parallelism",
+            "fuse_gemm_comms": "Async TP",
+            "fuse_allreduce_rms": "AllReduce + RMSNorm fusion",
+            "fuse_norm_quant": "RMSNorm + quant fusion",
+            "fuse_act_quant": "Activation + quant fusion",
+            "fuse_attn_quant": "Attention + quant fusion",
+            "fuse_act_padding": "Activation + padding fusion",
+            "fuse_rope_kvcache": "RoPE + KV cache fusion",
+        }
+        for flag, feature_name in fusion_passes_to_disable.items():
+            if getattr(pass_config, flag):
+                logger.warning(
+                    "Feature %r is not yet supported on XPU and will be disabled.",
+                    feature_name,
+                )
+                setattr(pass_config, flag, False)
+
         # check and update parallel config
         parallel_config = vllm_config.parallel_config
         # Only override worker_cls if it's still the default "auto"