[Bug tree-optimization/52254] VRP does not fold (~a) & N to a ^ N if a has range [0, N]

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52254

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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           Severity|normal                      |enhancement

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-02-15 11:21:53 UTC ---
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)