[Bugfix] Added missing thread offsets and other information to reduce. (#646)

src/tl_templates/cuda/reduce.h

@@ -42,7 +42,8 @@ struct AllReduce {
     if constexpr (offset == scale) {
       return x;
     } else {
-      return AllReduce<Reducer, offset, scale>::run(x, red_buf);
+      return AllReduce<Reducer, offset, scale, thread_offset, all_threads>::run(
+          x, red_buf);
     }
   }
 
@@ -51,7 +52,7 @@ struct AllReduce {
     constexpr int offset = threads / 2;
     if constexpr (offset >= 32) {
       asm volatile("bar.sync %0, %1;" : : "r"(1), "r"(all_threads));
-      red_buf[threadIdx.x] = x;
+      red_buf[threadIdx.x - thread_offset] = x;
       // TODO(lei): maybe we can merge the two bar.sync into one?
       asm volatile("bar.sync %0, %1;" : : "r"(2), "r"(all_threads));
       x = Reducer()(x, red_buf[(threadIdx.x - thread_offset) ^ offset]);
@@ -61,8 +62,8 @@ struct AllReduce {
     if constexpr (offset == scale) {
       return x;
     } else {
-      return AllReduce<Reducer, offset, scale, all_threads>::run_hopper(
-          x, red_buf);
+      return AllReduce<Reducer, offset, scale, thread_offset,
+                       all_threads>::run_hopper(x, red_buf);
     }
   }
 };