[Bug libfortran/114618] Format produces incorrect output when contains 1x, ok when uses " "

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114618

Jerry DeLisle <jvdelisle at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jvdelisle at gcc dot 
gnu.org

--- Comment #5 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
A further reduction:

program tryit
   implicit none
   integer, parameter :: wp = kind(0d0)
   real(kind=wp) :: pi  =
3.14159265358979323846264338327950288419716939937510582097494459230_wp
   character(40) gen1
   character(40) gen2
   gen1 = '(19("."),t1,g0,1x,t21,g0)'
   gen2 = '(19("."),t1,g0," ",t21,g0)'

   write (*, gen1) 'RADIX', radix(pi)
   write (*, gen1) 'RANGE', range(pi)
   write (*,'(80("-"))')
   write (*, gen2) 'RADIX', radix(pi)
   write (*, gen2) 'RANGE', range(pi)
end program tryit

This is indeed ugly. Note the embedded NULLs.

$ ./a.out >newdata
$ xxd newdata
00000000: 5241 4449 582e 2e2e 2e2e 2e2e 2e2e 2e2e  RADIX...........
00000010: 2e2e 2e00 0000 0000 0000 0000 0000 0000  ................
00000020: 0020 320a 5241 4e47 452e 2e2e 2e2e 2e2e  . 2.RANGE.......
00000030: 2e2e 2e2e 2e2e 2e00 0000 0000 0000 0000  ................
00000040: 0000 0000 0020 3330 370a 2d2d 2d2d 2d2d  ..... 307.------
00000050: 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d  ----------------
00000060: 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d  ----------------
00000070: 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d  ----------------
00000080: 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d 2d2d  ----------------
00000090: 2d2d 2d2d 2d2d 2d2d 2d2d 0a52 4144 4958  ----------.RADIX
000000a0: 202e 2e2e 2e2e 2e2e 2e2e 2e2e 2e2e 2032   ............. 2
000000b0: 0a52 414e 4745 202e 2e2e 2e2e 2e2e 2e2e  .RANGE .........
000000c0: 2e2e 2e2e 2033 3037 0a                   .... 307.