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[Bug tree-optimization/18694] [4.0 regression] loop miscompilation at -O1 (-ftree-ch)
- From: "kazu at cs dot umass dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 10 Dec 2004 20:14:34 -0000
- Subject: [Bug tree-optimization/18694] [4.0 regression] loop miscompilation at -O1 (-ftree-ch)
- References: <20041127224610.18694.falk@debian.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From kazu at cs dot umass dot edu 2004-12-10 20:14 -------
Subject: Re: [4.0 regression] loop
miscompilation at -O1 (-ftree-ch)
Hi Jeff,
> BTW, I may have a nice clean way to deal with this problem which doesn't
> depend on us not walking the SSA_NAME_VALUE chain.
>
> I'm looking into it now...
That would be great.
FYI, the only reason I am sticking to correct maintanance of
SSA_NAME_VALUE is that thread_across_edge is not the only function
that translates PHI results to PHI arguments on edge E.
lookup_avail_expr, for example, also uses SSA_NAME_VALUE, and we do
call lookup_avail_expr at tree-ssa-dom.c:582 without translating PHI
arguments on our own.
Kazu Hirata
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18694