postincrement behaviour (differences between dmd and gdc)

[Iain Buclaw]

This was partially discussed before some time ago -
http://www.digitalmars.com/d/archives/digitalmars/D/postincrement_behaviour_differences_between_dmd_and_gdc_47334.html


The following statement has different behaviours in dmd and gdc.

int x;
x = x++;


Where the backend for DMD interprets it as:

  tmp = x;
  x++;
  x = tmp;

And the backend for GDC interprets it as:

  x = x;
  x++;


Skipping all undefined behaviour/which one is correct talk, an alternative
suggestion would be to treat such nonsensical code as an error - like "Cannot
modify the value of a variable twice in the same expression." - as this kind
of thing I would expect to be almost always a bug.


Regards