[PATCH] Allow global structures to be vectorized

[Renato Golin]

Hi Arnold,

Thanks for the review. Please note that the patch is not ready, I'm looking
for ideas... not final code review. ;)


On 6 February 2013 17:03, Arnold Schwaighofer <aschwaighofer at apple.com>wrote:

> I don't think this is correct. You are asserting that: "Two geps will only
> alias if they have the same elements in the index list"?
>

I *know* it's not correct. I should have been a bit more clear about that
in my first email... ;)

I haven't put in proper alias analysis yet, just trying to see if the
skeleton of the code makes sense. Ignore the checks and alias analysis, for
now...

My plan is to add the AA steps directly on the WriteObjects values, but I
don't know at which level it'd be more effective (instruction, or
underlying value). If I do at the value level, I lose the instruction and
thus the GEP info. If I do at the instruction level, I can't match reads
against writes.

My question for this iteration is: To make it easier for the Alias Analysis
(which I still don't know how to do but am guessing something to do
with AliasAnalysis::alias(Loc, Loc)), what should I keep in the Set?

I could keep the Location of each access, so that on the read part, I'd
just ask:

  if (AliasAnalysis::alias(PrevWriteLoc, ThisReadLoc))) { BAD! }

Would that take care of all cases? Would that be sensible?

cheers,
--renato
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