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[Bug middle-end/51994] [4.6/4.7 Regression] git-1.7.8.3 miscompiled due to negative bitpos from get_inner_reference
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 01 Feb 2012 15:41:15 +0000
- Subject: [Bug middle-end/51994] [4.6/4.7 Regression] git-1.7.8.3 miscompiled due to negative bitpos from get_inner_reference
- Auto-submitted: auto-generated
- References: <bug-51994-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51994
--- Comment #27 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-02-01 15:41:15 UTC ---
(In reply to comment #25)
> I've changed my mind: given that we shouldn't have references outside the base
> object in valid programs, there must be an offset if the bitpos is negative, so
> we can simply add the (rounded) latter to the former. That's what the callers
> would have to do anyway, so we'd better factor it in get_inner_reference.
I'm not sure it's the best thing to do (adjusting 'offset' by
a BITS_PER_UNIT multiple instead of whatever the caller would like the most).
Only the callers would know how they want to adjust for negative bitpos.