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Puzzling Bug in FTN95 7.10

 
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mecej4



Joined: 31 Oct 2006
Posts: 1886
PostPosted: Sun Apr 26, 2015 2:20 pm    Post subject: Puzzling Bug in FTN95 7.10 Reply with quote
There is a puzzling code generation bug that is exposed by the following example code, which may look silly because lots of lines were removed to reduce its size while preserving the bug.
Code:
program mistfile
implicit none
real :: e6a=1,e6b=2,e6c
namelist /nex/e6a,e6b,e6c
!
e6c=e6a+e6b
write(*,nml=nex)
stop
!
contains
!
real function ssbw()
implicit none
real :: s1
namelist /nsbw/s1
ssbw=0
return
end function ssbw
!
end program

The contained function is never invoked, and within the function the namelist nbw is not referenced. The bug disappears if the function code is removed or if just the namelist declaration is removed!

When the code is compiled and run, an access violation occurs at main+0030H. The instruction at this location is
Code:
mov [ebx-0x10],edi
and the bug is that ebx (which I suspect is used by mistake instead of ebp) was never assigned a value in the program -- it retains whatever value was set into that register in the earlier call to ___FTN95INIT1_ in SALFLIBC.DLL.

[P.S., 15 June 2015: This bug is also present in FTN95-7.20]

Last edited by mecej4 on Mon Jun 15, 2015 11:23 pm; edited 3 times in total
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PaulLaidler
Site Admin


Joined: 21 Feb 2005
Posts: 7923
Location: Salford, UK
PostPosted: Mon Apr 27, 2015 6:04 am    Post subject: Reply with quote
Thanks for this bug report. I have logged it for investigation.
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PaulLaidler
Site Admin


Joined: 21 Feb 2005
Posts: 7923
Location: Salford, UK
PostPosted: Wed Jun 08, 2016 7:43 am    Post subject: Reply with quote
This has now been fixed for the next release.
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