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[Bug tree-optimization/54014] Value Range propagation bug
- 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, 18 Jul 2012 11:44:26 +0000
- Subject: [Bug tree-optimization/54014] Value Range propagation bug
- Auto-submitted: auto-generated
- References: <bug-54014-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54014
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-18 11:44:26 UTC ---
The VRP claims that (unsigned int) ABS (yy) is in the range [1, 2147483647] but
the actual range should be [1, 2147483648]. Everything seems to be related to
the managing of -(-2147483648).
abs () on an int is in the range [0, 2147483647], converting that to
unsigned does not increase that range. You probably want a ABSU function
which returns an unsigned number - but that does not exist.