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[Bug tree-optimization/52254] VRP does not fold (~a) & N to a ^ N if a has range [0, N]
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 16 Feb 2012 03:00:22 +0000
- Subject: [Bug tree-optimization/52254] VRP does not fold (~a) & N to a ^ N if a has range [0, N]
- Auto-submitted: auto-generated
- References: <bug-52254-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52254
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-16 03:00:22 UTC ---
(In reply to comment #2)
> The combine stage should have access to a valueize() hook as well, to query
> SSA propagator/VNs lattice. That hook can maybe supply this extra info
> (I wanted to make VRP info persistent for some time, in SSA_NAME_PTR_INFO
> much like we have alignment info there which really is kind of a value-range)
I was thinking about adding that. Even using nonzero bits to create a simple
range.