Ada front-end depends on signed overflow

[Robert Dewar]

  * Paul Schlie:

>  (With an exception being FP optimization, as FP is itself based
>   only on the approximate not absolute representation of values.)

Floating-point arithmetic is not simply some inaccurate representation
of real arithmetic. It can be used this way by the programmer, but in
fact fpt operations have very well defined semantics, and compiler
writers have to be very careful not to intefere with these semantics
beyond the level permitted by the language. Certainly the above quoted
attitude would be pretty deadly if held by a compiler optimizer
writer!