GIMPLE issues and status of gimple-tuples

[Daniel Berlin]

a a. Conditional jumps in GIMPLE are not true three-address-code since they
> specify two (2) branch targets (in their general form). E.g.:
>
> if (cond) then
>   goto target1;
> else
>   goto target2;
>
> IMHO, this should be split (or at least made splittable) into:
>
> if (cond) then
>   goto target1;
> if (!cond) then
>   goto target2;
>
> It seems redundant but it's really clean.

Branches are already special in a lot of ways, so whether they have
one argument or two doesn't seem to make any real difference.



> b. Are LOOP_EXPRs decomposable to combinations of if-then-else and gotos? It
> would help for VM (virtual machine) execution of GIMPLE IR. Ideally, a GIMPLE
> representation of a program should be possible without use of LOOP_EXPRs.

Errr, LOOP_EXPR doesn't actually exist anymore :)

Loops are always lowered to if-then-else and gotos.

>
> c. It would be interesting to support simple if-then statements in GIMPLE. I.e.
> that do not contain blocks of statements with size larger than one.

Now *this* would be ugly, IMHO, because you'd have to special case
these everywhere.

>
>