[Bug fortran/111837] [8/9/10/11/12/13/14 Regression] Out of bounds access with optimization inside io-implied-do-control

[anlauf at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111837

--- Comment #2 from anlauf at gcc dot gnu.org ---
Lightly tested, probably obvious patch:

diff --git a/gcc/fortran/frontend-passes.cc b/gcc/fortran/frontend-passes.cc
index 136a292807d..536884b13f0 100644
--- a/gcc/fortran/frontend-passes.cc
+++ b/gcc/fortran/frontend-passes.cc
@@ -1326,7 +1326,7 @@ traverse_io_block (gfc_code *code, bool *has_reached,
gfc_code *prev)
       if (iters[i])
        {
          gfc_expr *var = iters[i]->var;
-         for (int j = i - 1; j < i; j++)
+         for (int j = 0; j < i; j++)
            {
              if (iters[j]
                  && (var_in_expr (var, iters[j]->start)