[Patch, fortran] PR29821 - Ping

[Jerry DeLisle]

Paul Thomas wrote:
> Ping!
> 
> See: http://gcc.gnu.org/ml/fortran/2006-11/msg00577.html
> 
> This ice-on-valid-code fix was posted on 21st Novemeber.
> 
> Paul
>> :ADDPATCH fortran:
>>
>> This patch and its testcase are self-explanatory. I spent a lot of 
>> time trying to fix the rules of engagement of gfc_simplify_expr, as 
>> described in its heading comment.  In principle, this should return 
>> FAILURE only if an error has been found.  If simplification has not 
>> occurred, it should be up to the caller to detect this.  Apparently, 
>> this rule has been multiply violated and FAILURE is being used to 
>> indicate a lack of simplification.  The most immediate example of this 
>> is my fault; in find_array_section, where non-constant index 
>> expressions return FAILURE.  Changing this to SUCCESS fixes this 
>> problem but breaks other things.   Fixing those, cascades down to 
>> cause more breakages.  I therefore took a middle path and did a test 
>> in the caller, which is resolve_operator here, to see if the 
>> expression is constant before returning the result of the  call to 
>> gfc_simplify_expr.  In fact, I am not convinced that the result should 
>> be returned here at all - removing it breaks nothing.  I would be open 
>> to the reviewer suggesting that course of action :-)
>>
>> Regtested on suse10.1/amd64  - OK for trunk, 4.2 and 4.1?
>>
>> Paul
>>
>> 2006-11-21 Paul Thomas  <pault@gcc.gnu.org>
>>
>>    PR fortran/29821
>>    * resolve.c (resolve_operator): Only return result of
>>    gfc_simplify_expr if expression is constant.
>>
>> 2006-11-21 Paul Thomas  <pault@gcc.gnu.org>
>>
>>    PR fortran/29821
>>    * gfortran.dg/parameter_array_section_1.f90: New test.
>>
>> ------------------------------------------------------------------------
>>
>> Index: gcc/fortran/resolve.c
>> ===================================================================
>> *** gcc/fortran/resolve.c    (revision 118704)
>> --- gcc/fortran/resolve.c    (working copy)
>> *************** resolve_operator (gfc_expr * e)
>> *** 2199,2205 ****
>>       /* Attempt to simplify the expression.  */
>>     if (t == SUCCESS)
>> !     t = gfc_simplify_expr (e, 0);
>>     return t;
>>     bad_op:
>> --- 2199,2212 ----
>>       /* Attempt to simplify the expression.  */
>>     if (t == SUCCESS)
>> !     {
>> !       t = gfc_simplify_expr (e, 0);
>> !       /* Some calls do not succeed in simplification and return FAILURE
>> !      even though there is no error; eg. variable references to
>> !      PARAMETER arrays.  */
>> !       if (!gfc_is_constant_expr (e))
>> !     t = SUCCESS;
>> !     }
>>     return t;
>>     bad_op:
>> Index: gcc/testsuite/gfortran.dg/parameter_array_section_1.f90
>> ===================================================================
>> *** gcc/testsuite/gfortran.dg/parameter_array_section_1.f90    
>> (revision 0)
>> --- gcc/testsuite/gfortran.dg/parameter_array_section_1.f90    
>> (revision 0)
>> ***************
>> *** 0 ****
>> --- 1,24 ----
>> + ! { dg-do compile }
>> + ! Tests the fix for PR29821, which was due to failure to simplify the
>> + ! array section, since the section is not constant, provoking failure
>> + ! to resolve the argument of SUM and therefore to resolve SUM itself.
>> + !
>> + ! Contributed by Harald Anlauf  <anlauf@gmx.de>
>> + !
>> + module gfcbug45
>> +   implicit none
>> + contains
>> +   subroutine foo +     real, external :: mysum
>> +     integer :: i
>> +     real    :: a
>> +     real, parameter :: eps(2) = (/ 1, 99 /)
>> +     i = 1
>> +     a = sum (eps(i:i+1) * eps)
>> +     print *, a
>> +   end subroutine foo
>> + end module gfcbug45
>> +   use gfcbug45
>> +   call foo
>> + end
>> + ! { dg-final { cleanup-modules "gfcbug45" } }
>>
>>   
>> ------------------------------------------------------------------------
>>
>> 2006-11-21 Paul Thomas  <pault@gcc.gnu.org>
>>
>>     PR fortran/29821
>>     * resolve.c (resolve_operator): Only return result of
>>     gfc_simplify_expr if expression is constant.
>>
>> 2006-11-21 Paul Thomas  <pault@gcc.gnu.org>
>>
>>     PR fortran/29821
>>     * gfortran.dg/parameter_array_section_1.f90: New test.
>>
>>   
> 
> 
OK