[Bug optimization/13951] [tree-ssa] cselib ICE during x86-64 kernel compile with treessa

[jh at suse dot cz]

------- Additional Comments From jh at suse dot cz  2004-02-05 08:35 -------
Subject: Re:  [tree-ssa] cselib ICE during  x86-64 kernel compile with treessa

> On Thu, Feb 05, 2004 at 12:56:58AM +0100, Jan Hubicka wrote:
> > > I think CSELIB ICE because dummy is set twice.  I think it makes sense
> > > to do so...
> 
> Why?  I think an ICE because of such isn't a good idea.

We care to not have undefined insns of this kind.
One never knows what of the sets will be winner and thus never knows the
effect of instructions.  Various optimizers may miss the detail and
choose one of the sets to be "the right one"
To deal with this correctly, we would have to teach cselib to track down
such a multi sets and invalidate result of the register immediately
after processing.
Not terribly dificult, but anoying.
Honza
> 
> 
> r~


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13951