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Re: [PR52001] too many cse reverse equiv exprs (take2)


On Feb 26, 2012, Richard Sandiford <rdsandiford@googlemail.com> wrote:

> It seemed that when we recorded two values V1 and V2 were equivalent,
> we added V1 to V2's location list and V2 to V1's location list.  But
> it sounds from the above like the canonical value is what we want in
> almost all cases, so if V2 is the one that becomes "noncanonical", is
> it really worth adding V2 to V1's location list?

I'd given that some thought and concluded that it wasn't safe to take V2
out of V1's list, in case what we were searching for among V1's
locations was precisely V2.  Now, maybe there are ways around that that
(say, canonicalizing a value before searching for it) that I haven't
given much thought.  I didn't think it would buy us much, but I could
easily be wrong, and I'd be glad to look into this given evidence that I
am.

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer


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