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Q104777: FIX: No F6099 with /4I2 and /4Yb on Integer Overflow

Article: Q104777
Product(s): Microsoft Fortran Compiler
Version(s): 4.0,4.01,4.1,5.0,5.1
Operating System(s): 
Keyword(s): 
Last Modified: 24-MAR-2000

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The information in this article applies to:

- Microsoft FORTRAN Compiler for MS-DOS, versions 4.0, 4.01, 4.1, 5.0, 5.1 
- Microsoft FORTRAN compiler for OS/2, versions 4.1, 5.0, 5.1 
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SYMPTOMS
========

Programs compiled with the $STORAGE:2 metacommand, the /4I2 option and $DEBUG
metacommand, or the /4Yb option, with integer variables taking values beyond
their full 16-bit range (-32,768 to 32,767), may not generate the following
error:

  Run-Time Error F6099: $DEBUG
  INTEGER overflow

CAUSE
=====

The $STORAGE:2 metacommand, /4I2 option and $DEBUG metacommand, or the /4Yb
option does not cause the compiler to generate additional code that will lead to
a jump to the overflow routine for integer values that are out of range. This
incorrect code generation is due to the common subexpression elimination
optimization.

RESOLUTION
==========

To correctly generate this error message for integer values that are out of the
integer*2 (16-bit) range, compile with the /Od switch to disable optimization.
Optimization may be partially turned back on with the optimization switches:
/Os, /Ot, and /Ol (which do not enable common subexpression elimination /Oc).

STATUS
======

Microsoft has confirmed this to be a problem in FORTRAN versions 4.0, 4.01, 4.1,
5.0, and 5.1. This problem was corrected in FORTRAN PowerStation, version 1.0.

MORE INFORMATION
================

The following code does generate the F6099 error if compiled with the partial
optimization of /Odlt, but will not generate the error if complied with either
the default full optimization "/Ox" or common subexpression elimination "/Odc":

Sample Code
-----------

  $debug
  $storage:2

        integer*2 i,j,k

        i=10
        j=4000
        k=i*j
        end

Additional query words: 4.00 4.01 4.10 5.00 5.10 buglist4.00 buglist4.01 buglist4.10 buglist5.00 buglist5.10 fixlist1.00

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Keywords          :  
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword3 kbFORTRAN510DOS kbFORTRAN400DOS kbFORTRAN401DOS kbFORTRAN500DOS kbFORTRAN410DOS kbFORTRAN500OS2 kbFORTRAN510OS2 kbFORTRAN410OS2
Version           : :4.0,4.01,4.1,5.0,5.1
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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