[Bug rtl-optimization/55489] [4.7/4.8 regression] insane PRE memory usage with PIE (translate.i)

["bonzini at gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55489

Paolo Bonzini <bonzini at gnu dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|4.8.0                       |
            Summary|[4.7 regression] insane PRE |[4.7/4.8 regression] insane
                   |memory usage with PIE       |PRE memory usage with PIE
                   |(translate.i)               |(translate.i)
      Known to fail|                            |4.8.0

--- Comment #1 from Paolo Bonzini <bonzini at gnu dot org> 2012-11-27 15:50:44 UTC ---
Strictly not a regression, because the underlying bug is present since always. 
But something between 4.4.6 and 4.7.2 caused memory usage to become much worse.

Also, marking it as not-working in 4.8 because the allocation of
reg_known_value is wrong:

  vec_alloc (reg_known_value, maxreg - FIRST_PSEUDO_REGISTER);

and that's what causes the bug to be latent: set_reg_known_value becomes a
no-op, and get_reg_known_value always returns NULL.