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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug fortran/102043] Wrong array types used for negative stride
 accesses
Date: Wed, 25 Aug 2021 08:42:27 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102043

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-08-25
     Ever confirmed|0                           |1
      Known to fail|                            |11.2.1, 12.0, 7.5.0
      Known to work|                            |4.3.5

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Testcase, FAILs at -O1, FRE concludes the idx(2:1:-1) load is always '2'.  =
At
-O2 we unroll the loop mitigating the issue.

program main
   integer, dimension (2) :: idx, a, b
   a =3D (/ 0, 0 /)
   idx =3D (/ 1, 2 /)
   a(idx(2:1:-1)) =3D idx
   if (a(1).ne.2) STOP 1
end program main=