[ROCm][Bugfix] Fix compilation error in topk softmax fused kernel (#22819)

Signed-off-by: kliuae <kuanfu.liu@embeddedllm.com>

csrc/moe/topk_softmax_kernels.cu

@@ -423,12 +423,27 @@ void topkGatingSoftmaxLauncherHelper(const float* input, const bool* finished, f
         input, finished, output, num_rows, indices, source_row, k, start_expert, end_expert);
 }
 
+#ifndef USE_ROCM
 #define LAUNCH_SOFTMAX(NUM_EXPERTS, WARPS_PER_TB, MAX_BYTES)                          \
-    static_assert(WARP_SIZE == 32 || WARP_SIZE == 64,                                 \
-                  "Unsupported warp size. Only 32 and 64 are supported.");            \
+    static_assert(WARP_SIZE == 32,                                                    \
+                  "Unsupported warp size. Only 32 is supported for CUDA");            \
     topkGatingSoftmaxLauncherHelper<NUM_EXPERTS, WARPS_PER_TB, WARP_SIZE, MAX_BYTES>( \
         gating_output, nullptr, topk_weights, topk_indices,                           \
         token_expert_indices, num_tokens, topk, 0, num_experts, stream);
+#else
+#define LAUNCH_SOFTMAX(NUM_EXPERTS, WARPS_PER_TB, MAX_BYTES)                             \
+    if (WARP_SIZE == 64) {                                                               \
+        topkGatingSoftmaxLauncherHelper<NUM_EXPERTS, WARPS_PER_TB, 64, MAX_BYTES>(       \
+            gating_output, nullptr, topk_weights, topk_indices,                          \
+            token_expert_indices, num_tokens, topk, 0, num_experts, stream);             \
+    } else if (WARP_SIZE == 32) {                                                        \
+        topkGatingSoftmaxLauncherHelper<NUM_EXPERTS, WARPS_PER_TB, 32, MAX_BYTES>(       \
+            gating_output, nullptr, topk_weights, topk_indices,                          \
+            token_expert_indices, num_tokens, topk, 0, num_experts, stream);             \
+    } else {                                                                             \
+        assert(false && "Unsupported warp size. Only 32 and 64 are supported for ROCm"); \
+    }
+#endif
 
 template <typename IndType>
 void topkGatingSoftmaxKernelLauncher(
@@ -443,7 +458,9 @@ void topkGatingSoftmaxKernelLauncher(
     cudaStream_t stream) {
     static constexpr int WARPS_PER_TB = 4;
     static constexpr int BYTES_PER_LDG_POWER_OF_2 = 16;
+#ifndef USE_ROCM
     static constexpr int BYTES_PER_LDG_MULTIPLE_64 = 8;
+#endif
     switch (num_experts) {
         case 1:
             LAUNCH_SOFTMAX(1, WARPS_PER_TB, BYTES_PER_LDG_POWER_OF_2);