https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80155

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot 
gnu.org

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Can you benchmark the 2nd candidate (most appropriate at this stage I think,
would also fix 77498).

It will cause pessimizations for code that benefits from predictive commoning
transforms that PRE can do at -O2 because predictive commoning doesn't run at
-O2.
The fix for that would be to run predictive commoning at -O2 but in a mode
that doesn't perform unrolling for example.  [even pcom can blow through
register pressure limits though]

Any other approach to fixing this particular bug cannot be done for GCC 7 (even
this one is quite late ...).  So in the end I'd vote for WONTFIX for GCC 7.

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