atomicLoad/Store

[zyhong]

 From my understanding, any data type that is less than 32bit 
(bool, char, int, etc) is atomic and there is no need to use 
atomicLoad/Store and read/write the data to be thread safe. In 
std.parallelism, I saw it use atomicLoad/Store for any shared 
data. Could anyone clarify if it is really necessary to 
atomicLoad/Store to read/write data that datatype is bool, int, 
byte, etc?