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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, 25 Jan 2012 10:56:37 +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
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-01-25
CC| |ebotcazou at gcc dot
| |gnu.org
Component|tree-optimization |middle-end
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-25 10:56:37 UTC ---
Negative bitpos is fine - Ada uses that quite extensively and with MEM_REFs
this just got more prominent. get_inner_reference is declared to return
a _signed_ HOST_WIDE_INT bitpos for a reason.
What should happen instead is that store_field needs to adjust the address
to properly point before the bitfield for calling store_bit_field. Or the
latter needs to take signed arguments for bitpos and do the adjustment
itself.
Does simply changing the store_bit_field[_1] prototype work for you?