[Bug fortran/82243] New: -fcheck=bounds not checking, and behaving differently with different real kinds

["john.harper at vuw dot ac.nz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82243

            Bug ID: 82243
           Summary: -fcheck=bounds not checking, and behaving differently
                    with different real kinds
           Product: gcc
           Version: 6.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: john.harper at vuw dot ac.nz
  Target Milestone: ---

-fcheck=bounds doesn't complain if LHS and RHS of real array assignments in a
subroutine are different shapes. Gfortran's behaviour depends on kind(s).

! array section assigned to array constructor of wrong shape in subroutine.
! Run-time abort if mp = kind(1d0) but no error message if mp = kind(1.0)
! Should gfortran -fcheck=bounds pick up the error? 

module globals
  implicit none
  integer,parameter::  mp = kind(1d0)
contains
  subroutine finds(     n,s) 
    integer,intent(in)::n
    real(mp),intent(out)::s(0:)
    real(mp),dimension(0:n/2+1):: even
    integer:: i
    even = 1.0_mp
    s(0) = even(1)
    s(2:n-1:2) = [(even(i),i=1,n/2)]
    print *,'Sizes: LHS',size(s(2:n-1:2)),'RHS',size(even(1:n/2))
  end subroutine finds
end module globals

program gfbug3
  use globals, only: mp,finds
  implicit none
  integer:: n = 40 
  real(mp),allocatable:: s(:)
  allocate(s(0:n))
  print *,merge('Single','Double',mp==kind(1.0))//' precision'
  call finds(n,s)
  print "(20F3.0)",s(0::2)
end program gfbug3

The output did reveal the offending line:

cayley[~/Jfh] % gfortran -g -fcheck=bounds gfbug3.f90
cayley[~/Jfh] % ./a.out
 Double precision
*** Error in `./a.out': double free or corruption (!prev): 0x00000000012fb170
***
======= Backtrace: =========
/usr/lib/libc.so.6(+0x70c4b)[0x7f1e39b76c4b]
/usr/lib/libc.so.6(+0x76fe6)[0x7f1e39b7cfe6]
/usr/lib/libc.so.6(+0x777de)[0x7f1e39b7d7de]
./a.out[0x400e13]
./a.out[0x401365]
./a.out[0x4015f9]
/usr/lib/libc.so.6(__libc_start_main+0xf1)[0x7f1e39b26291]
./a.out[0x40088a]
======= Memory map: ========
00400000-00402000 r-xp 00000000 00:2b 11619110                          
/am/roxy/home/harper/Jfh/a.out
00601000-00602000 r--p 00001000 00:2b 11619110                          
/am/roxy/home/harper/Jfh/a.out
00602000-00603000 rw-p 00002000 00:2b 11619110                          
/am/roxy/home/harper/Jfh/a.out
012f8000-01319000 rw-p 00000000 00:00 0                                  [heap]
7f1e34000000-7f1e34021000 rw-p 00000000 00:00 0 
7f1e34021000-7f1e38000000 ---p 00000000 00:00 0 
7f1e39b06000-7f1e39c9b000 r-xp 00000000 08:03 1221622                   
/usr/lib/libc-2.24.so
7f1e39c9b000-7f1e39e9a000 ---p 00195000 08:03 1221622                   
/usr/lib/libc-2.24.so
7f1e39e9a000-7f1e39e9e000 r--p 00194000 08:03 1221622                   
/usr/lib/libc-2.24.so
7f1e39e9e000-7f1e39ea0000 rw-p 00198000 08:03 1221622                   
/usr/lib/libc-2.24.so
7f1e39ea0000-7f1e39ea4000 rw-p 00000000 00:00 0 
7f1e39ea4000-7f1e39ee3000 r-xp 00000000 08:03 1222012                   
/usr/lib/libquadmath.so.0.0.0
7f1e39ee3000-7f1e3a0e2000 ---p 0003f000 08:03 1222012                   
/usr/lib/libquadmath.so.0.0.0
7f1e3a0e2000-7f1e3a0e3000 r--p 0003e000 08:03 1222012                   
/usr/lib/libquadmath.so.0.0.0
7f1e3a0e3000-7f1e3a0e4000 rw-p 0003f000 08:03 1222012                   
/usr/lib/libquadmath.so.0.0.0
7f1e3a0e4000-7f1e3a0fa000 r-xp 00000000 08:03 1221717                   
/usr/lib/libgcc_s.so.1
7f1e3a0fa000-7f1e3a2f9000 ---p 00016000 08:03 1221717                   
/usr/lib/libgcc_s.so.1
7f1e3a2f9000-7f1e3a2fa000 r--p 00015000 08:03 1221717                   
/usr/lib/libgcc_s.so.1
7f1e3a2fa000-7f1e3a2fb000 rw-p 00016000 08:03 1221717                   
/usr/lib/libgcc_s.so.1
7f1e3a2fb000-7f1e3a3fe000 r-xp 00000000 08:03 1221842                   
/usr/lib/libm-2.24.so
7f1e3a3fe000-7f1e3a5fd000 ---p 00103000 08:03 1221842                   
/usr/lib/libm-2.24.so
7f1e3a5fd000-7f1e3a5fe000 r--p 00102000 08:03 1221842                   
/usr/lib/libm-2.24.so
7f1e3a5fe000-7f1e3a5ff000 rw-p 00103000 08:03 1221842                   
/usr/lib/libm-2.24.so
7f1e3a5ff000-7f1e3a72d000 r-xp 00000000 08:03 1221728                   
/usr/lib/libgfortran.so.3.0.0
7f1e3a72d000-7f1e3a92d000 ---p 0012e000 08:03 1221728                   
/usr/lib/libgfortran.so.3.0.0
7f1e3a92d000-7f1e3a92e000 r--p 0012e000 08:03 1221728                   
/usr/lib/libgfortran.so.3.0.0
7f1e3a92e000-7f1e3a930000 rw-p 0012f000 08:03 1221728                   
/usr/lib/libgfortran.so.3.0.0
7f1e3a930000-7f1e3a953000 r-xp 00000000 08:03 1221559                   
/usr/lib/ld-2.24.so
7f1e3ab30000-7f1e3ab34000 rw-p 00000000 00:00 0 
7f1e3ab51000-7f1e3ab52000 rw-p 00000000 00:00 0 
7f1e3ab52000-7f1e3ab53000 r--p 00022000 08:03 1221559                   
/usr/lib/ld-2.24.so
7f1e3ab53000-7f1e3ab54000 rw-p 00023000 08:03 1221559                   
/usr/lib/ld-2.24.so
7f1e3ab54000-7f1e3ab55000 rw-p 00000000 00:00 0 
7ffd0abcc000-7ffd0abed000 rw-p 00000000 00:00 0                         
[stack]
7ffd0abf2000-7ffd0abf4000 r--p 00000000 00:00 0                          [vvar]
7ffd0abf4000-7ffd0abf6000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                 
[vsyscall]

Program received signal SIGABRT: Process abort signal.

Backtrace for this error:
#0  0x7f1e39b390af in ???
#1  0x7f1e39b3904f in ???
#2  0x7f1e39b3a479 in ???
#3  0x7f1e39b76c4f in ???
#4  0x7f1e39b7cfe5 in ???
#5  0x7f1e39b7d7dd in ???
#6  0x400e12 in __globals_MOD_finds
        at /home/harper/Jfh/gfbug3.f90:15
#7  0x401364 in gfbug3
        at /home/harper/Jfh/gfbug3.f90:27
#8  0x4015f8 in main
        at /home/harper/Jfh/gfbug3.f90:21
Abort