Semi-Latent Bug in tree vectorizer

[Andrew MacLeod]

On Fri, 2005-04-08 at 13:27, Andrew MacLeod wrote:
> On Fri, 2005-04-08 at 12:52, Jeffrey A Law wrote:
> 

actually, I'll jsut keep talking to myself here :-)

> > In the interest of brevity, I'm just going to point out the
> > problematical store from the .ifcvt dump:
> > 
> > 
> >   #   x_16 = V_MAY_DEF <x_21>;
> >   #   SFT.3_20 = V_MAY_DEF <SFT.3_15>;
> >   *D.1470_8 = D.1472_11;
> > 
> > Which gets vectorized and appears like this in the .vect dump:
> > 
> > 
> > 
> >   #   x_16 = V_MAY_DEF <x_21>;
> >   #   SFT.3_20 = V_MAY_DEF <SFT.3_15>;
> >   *vect_px.17_36 = vect_var_.10_29;

> What are these uses?  If they are references to things that aliased
> *D.1470_8, we should eliminate the VUSE/MAYDEF, shouldnt we? I presume
> they arent relevant any more if vec_px.17 isnt in the same alias set.
> 
> And if they are relevant, then we need to find out what the new variable
> is, and change all the uses to the new one
> 

you don't delete references to SFT.3_20, you rewrite any uses of
SFT.3_20 with the RHS of the MAY_DEF, so SFT.3_15...

Andrew