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[Bug middle-end/38934] [4.3/4.4 Regression] ICE in set_value_range, at tree-vrp.c:398
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 26 Jan 2009 16:07:13 -0000
- Subject: [Bug middle-end/38934] [4.3/4.4 Regression] ICE in set_value_range, at tree-vrp.c:398
- References: <bug-38934-7849@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #7 from rguenther at suse dot de 2009-01-26 16:07 -------
Subject: Re: [4.3/4.4 Regression] ICE in set_value_range,
at tree-vrp.c:398
On Mon, 26 Jan 2009, jakub at gcc dot gnu dot org wrote:
> ------- Comment #6 from jakub at gcc dot gnu dot org 2009-01-26 16:02 -------
> That brings us back to http://gcc.gnu.org/ml/gcc-patches/2008-11/msg00532.html
> If the gimplifier shouldn't drop TREE_OVERFLOW bits from the IL, then it is
> valid to have TREE_OVERFLOWs set and tree-vrp.c needs to deal with it (use
> VARYING range or something similar).
Not exactly. Your patch was correct in principle but exposed latent
bugs elsewhere. Difficult ones, because fold is shared between FEs
and the middle-end and fold and the FEs _do_ care about TREE_OVERFLOW.
...
So indeed, working around these issues where they pop up is the way
to go in the near future.
(this doesn't mean a TREE_OVERFLOW in the IL is valid ...)
Richard.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38934