[ROCM]fix bfloat16 to float error! (#56517)

Rane2021 · web-flow · commit b6786ff7bad9 · 2023-08-23T10:26:27.000+08:00
diff --git a/paddle/phi/common/bfloat16.h b/paddle/phi/common/bfloat16.h
@@ -157,7 +157,9 @@ struct PADDLE_ALIGN(2) bfloat16 {
     uint16_t temp = x;
     uint16_t* temp_ptr = reinterpret_cast<uint16_t*>(&temp);
     res = *temp_ptr;
-    return res;
+    // return res;
+    res = res << 16;
+    return *reinterpret_cast<float*>(&res);
 #else
 #ifdef PADDLE_CUDA_BF16
     return __bfloat162float(*reinterpret_cast<const __nv_bfloat16*>(&x));
