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Re: RFA: Don't destroy SCEV cache in copy-prop


On Fri, Nov 26, 2010 at 7:03 AM, Michael Matz <matz@suse.de> wrote:
> Hello,
>
> while working on something else I got a segfault in SCEV analysis because
> it contained stale SSA names. ?The reason is that copy-prop always DCEs
> the propagated copies, invalidating SCEV entries referring to the LHS of
> those. ?We could either reset the SCEV cache (at the expense of having to
> recompute it again), or simply not do DCE when we have loops. ?I chose the
> latter.
>
> I've also removed the superflous copy-prop in the graphite pipeline, it's
> no use to run two copy-props next to each other.
>
> Unfortunately I don't have a testcase that fails with an unmodified GCC.
>
> Regstrapping on x86_64-linux (all langs + Ada) in progress. ?Okay if that
> passes?
>
>

This caused:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46799

H.J.


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