2.1.20. ‑‑[no_]data_reorder
This option enables or disables automatic reordering of top‑level data items, for example global variables.
The compiler can save memory by eliminating wasted space between data items. However, ‑‑data_reorder can break legacy code, if the code makes invalid assumptions about ordering of data by the compiler.
The ISO C Standard does not guarantee data order, so you must avoid writing code that depends on any assumed ordering. If you require data ordering, place the data items into a structure.
The default is --data_reorder.