[Bug tree-optimization/42893] [4.3/4.4/4.5/4.6 Regression] Missed conditionally dead store elimination

[law at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42893

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |law at redhat dot com
         Resolution|                            |FIXED
   Target Milestone|4.3.6                       |4.6.0

--- Comment #10 from Jeffrey A. Law <law at redhat dot com> 2011-01-27 02:27:36 UTC ---
DSE1 removes tui_refreshing_registers = 1 as it's a dead store.

DOM2 then removes tui_refreshing_registers = 0 because it's able to prove the
memory location already holds the value 0.

That ultimately leaves an empty function as we leave the tree-ssa optimizers,
which is precisely what we want.