Re: [tree-ssa vs lno] who is right?

[Zdenek Dvorak <rakdver@atrey.karlin.mff.cuni.cz>]

Hello,

> When the LNO branch copies a loop, it attempts to fix up the phi nodes 
> with
> an algorithm that assumes there is only one phi per block per variable. 
>  That is, it
> won't see code like this:

where do we assume this (i.e. what do you mean by "copying a loop")?
While this certainly is unlikely to happen, there probably is nothing
that would prevent it.

Zdenek

> ;; basic block 19, loop depth 0, count 0
> ;; prev block 9, next block 20
> ;; pred:       10 [100.0%]  (fallthru)
> ;; succ:       28 [50.0%]  (true,exec) 29 [50.0%]  (false,exec)
> # maxmin_Result_140 = PHI <1(10)>;
> # maxmin_Result_142 = PHI <2(10)>;
> # lsm_tmp.19_144 = PHI <lsm_tmp.19_84(10)>;
> <L28>:;
> if (m__10 == 0) goto <L26>; else goto <L27>;
> 
> Is that suppose to be a valid assumption?  The dup is created by 
> copyrename, and
> I see no code there that's intended to stop dups from being created (on 
> the
> contrary, but surely it's unusual for the live ranges to overlap).
>