[Bug target/51134] [4.7 Regression] x86 memset/memcpy expansion is broken

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51134

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-11-18
     Ever Confirmed|0                           |1

--- Comment #7 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-11-18 01:03:17 UTC ---
I am testing patch fixing the Atom issues and other problems.

The gfortran.fortran-torture/execute/arrayarg.f90 testcase is however
different: the new inline code enables loop unrolling that in turn makes sched2
to produce wrong code.  The testcase passes with -fno-unroll-loop (or a hack
disabling only RTL unroller) as well as with -fno-schedule-insns2 added.

After hours looking into the code produced I am quite convinced that the memset
expansion involved is correct.  Can someone with better Fortran-fu than me
verify that the testcase is well defined WRT aliasing?

Honza