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[Bug tree-optimization/34176] [4.3 Regression] SCCVN breaks gettext
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 22 Nov 2007 15:08:33 -0000
- Subject: [Bug tree-optimization/34176] [4.3 Regression] SCCVN breaks gettext
- References: <bug-34176-10053@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #12 from rguenther at suse dot de 2007-11-22 15:08 -------
Subject: Re: [4.3 Regression] SCCVN breaks
gettext
On Thu, 22 Nov 2007, matz at gcc dot gnu dot org wrote:
> ------- Comment #11 from matz at gcc dot gnu dot org 2007-11-22 14:13 -------
> Btw. canonicalization/rewriting on INSERT is indeed okay. As long as the hash
> tables are deleted after every iteration (or otherwise invalidated). At least
> the now provably false information needs to be removed, which is a bit
> difficult to track when you do general rewriting, so invalidating the whole
> thing is probably easiest.
Though in the paper they state that they'd want to use the optimistic
hashtable entries for further SCC processing. In which case you'd either
have to invalidate only those entries you added during the current
iteration or maybe instead of invalidating it, initialize it with the
correct table contents.
Richard.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34176