g77 bug report

N8TM@aol.com N8TM@aol.com
Tue Nov 2 05:51:00 GMT 1999


In a message dated 11/2/99 7:35:38 AM EST, Jan.van.Eldik@cern.ch writes:

> Addition of "-ffloat-store" also gives the correct result.
the
resulting array overwrites the input array:
      CALL ETMUMA(DERA,POIA,POIA)
...
      SUBROUTINE ETMUMA(DER,WGTI,WGTO)
*   Calcul le produit WGTO = DER(trans)*WGTI*DER

This is specifically not permitted by the Fortran standards, although this 
practice was followed as a matter of routine for many years.  If there is 
failure when the arrays are kept separate, a bug report would be justified.  
IMO it is likely that it could be made to work by putting a function call or 
even by accessing COMMON between the section which uses WGTI and the section 
which uses WGTO, but there is no guarantee.  Commercial compilers generally 
require a special compiler option, analogous to gcc's -fno-strict-aliasing 
(which I don't expect to work here, as it applies to arrays of different type 
and not to g77).

Tim
tprince@computer.org


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