Q100377: FIX: F1001: confold.c Line 253, Negative Integer Exponent

Article: Q100377
Product(s): Microsoft Fortran Compiler
Version(s): 1.0,1.0a
Operating System(s): 
Keyword(s): kberrmsg kbCompiler kbFL32 kbFortranPS
Last Modified: 24-MAR-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0, 1.0a 
- Microsoft Fortran Powerstation 32 for Windows NT, version 1.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

An attempt to compile an application fails and Microsoft FORTRAN PowerStation
version 1.0 for MS-DOS displays the following message:

  fatal error F1001: INTERNAL COMPILER ERROR
  (compiler file '@(#)confold.c:1.144', line 253)
  Contact Microsoft Product Support Services

FORTRAN PowerStation version 1.0a for MS-DOS displays the following error
message:

  fatal error F1001: INTERNAL COMPILER ERROR
  (compiler file '@(#)confold.c:1.144', line 254)
  Contact Microsoft Product Support Services

CAUSE
=====

The command line specifies the /Ox optimization and the code contains an
expression that computes a negative integer power of a constant integer or of an
integer expression. The error above occurs when the compiler processes the unary
minus operator in an integer exponentiation expression.

RESOLUTION
==========

There are two methods to work around this problem:

- Modify the compiler command line to specify the /Oxp compiler option switch.

- Modify the source code to remove the unary minus operator from integer
  expressions used as exponents. Assign the exponent to a temporary variable
  and negate the value. Then specify the temporary as the exponent.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This problem was fixed in FORTRAN PowerStation
32, version 4.0.

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

The following sample code demonstrates this problem:

Sample Code #1
--------------

  c Compiler options needed: /Ox

        program test
        integer j
        real    x

        j = 1
        x = 2**(-j)
        print *, x
        end

The following sample code demonstrates one method to work around this problem:

Sample Code #2
--------------

  c Compile options needed: /Ox

        program test
        integer j
        real    x

        j = 1
        j = -j      ! Negation occurs here.
        x = 2**(j)
        print *, x
        end

Additional query words: 1.00 1.00a

======================================================================
Keywords          : kberrmsg kbCompiler kbFL32 kbFortranPS 
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword2 kbZNotKeyword3 kbFORTRANPower32100NT kbFORTRANPower100DOS kbFORTRANPower100aDOS
Version           : :1.0,1.0a
Issue type        : kbbug
Solution Type     : kbfix

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.