[Bug rtl-optimization/51978] ext-elim-1.c ICE on powerpc64

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51978

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-24
     Ever Confirmed|0                           |1

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2012-01-24 11:11:17 UTC ---
> The attached untested patch cures the ICE, still I wonder about the single_set
> instead of note_stores, I'd expect the pass isn't really prepared to handle
> multiple sets in parallel alongside with sign/zero extension anyway.

The patch looks fine to me.  Yes, single_set would probably be sufficient, as
merge_def_and_ext punts if there are multiple sets.

> Additionally, I wonder if some of the PR51667 additions couldn't be dropped
> again (4.8 material) now that we keep the UD/DU links for the whole duration of
> the pass.

There is a FIXME for this.