[Bug fortran/64854] No bound check for explicit-shape arrays

[anlauf at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64854

Harald Anlauf <anlauf at gmx dot de> changed:

           What    |Removed                     |Added
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                 CC|                            |anlauf at gmx dot de

--- Comment #3 from Harald Anlauf <anlauf at gmx dot de> ---
(In reply to Dominique d'Humieres from comment #1)
> Well, you give wrong information to the compiler. How do expect it to handle
> your mistake: in testsub -fcheck=bounds checks that n1<=i<=n2 which is the
> case. What you ask for is a check that a(n1:n2) is inside a(1:10), AFAIK
> such check is not implemented and I don't have any idea about how difficult
> it is to implement it.

valgrind detects this issue.

I was expected that the address sanitizer is able to handle it,
but I am getting linking errors on my system.

> I am inclined to close tis PR as INVALID or WONTFIX.

The right way to fix the problem is to fix the program
by using an appropriate programming style.  Writing

      real    :: a(n1:)   ! not:  real :: a(n1:n2)

one gets the expected check:

At line 22 of file pr64854.f90
Fortran runtime error: Index '1048586' of dimension 1 of array 'a' above upper
bound of 1048585

Backtrace for this error:
  + function testsub.3321 (0x80486A4)
    from file pr64854.f90
  + in the main program
    from file pr64854.f90
  + /lib/libc.so.6(__libc_start_main+0xf3) [0xb7424003]

I also suggest to close the PR.