Wrong translation of for in loop when using negative counts

[stephaneberle9]

E.g.:

for (i -- in [0..-262144]) { ... } for

should translate to

for ( int32_t __i = 0; __i >= -262144; __i-- ) ¨ { ... }

but actually results in

for ( int32_t __i = -262144; __i >= 0; __i-- ) { ... }

[DomenikP]

If you write a --, then the code generator always puts the upper bound as the starting value for the loop.

From my opinion, it makes sense to always (in the '++' and '--' case) use the lower bound as starting value and iterate to the upper bound.

[stephaneberle9]

If you write a --, then the code generator always puts the upper bound as the starting value for the loop.

That's absolutely not what one would expect intuitively. When I type -- then I do want the the iteration is counted down but not up.

[bkolb]

The problem is if the values are not statically known. What do you do then? It is hard to detect the correct behavior there.

[stephaneberle9]

I wouldn't expect the for loop statement to do any magic. If you write a traditional for loop with expressions that evaluate to nonsense kind of boundaries like this

for ( int32_t __i = 1; __i >= 10; __i-- ) ¨ { ... }

then it's also the programmer's own fault and he cannot expect to be "saved" by the C compiler.