https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71942
Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Target| |arm
Status|UNCONFIRMED |NEW
Last reconfirmed| |2016-07-20
Ever confirmed|0 |1
--- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
This is a well known problem. When a data object is marked volatile the
compiler is ultra-conservative about optimizing around it. The result is that
the load and the zero-extend get separated and then never merged back together
again.
