[Bug fortran/55214] New: Program fail to evaluate where clause

[Bug fortran/55214] New: Program fail to evaluate where clause

[pmarguinaud at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55214

             Bug #: 55214
           Summary: Program fail to evaluate where clause
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pmarguinaud@hotmail.com


LOGICAL :: L (2)
REAL    :: X (2), Y (2)

L (1) = .TRUE.
L (2) = .FALSE.
X (1) = +1
X (2) = -1
Y = 0.

WHERE (L)
  WHERE (SQRT(X)>0)
    Y = 1.
  END WHERE
END WHERE

PRINT *, Y

END

[Bug fortran/55214] Program fail to evaluate where clause

[pmarguinaud at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55214

--- Comment #1 from pmarguinaud at hotmail dot com 2012-11-05 14:03:32 UTC ---
$ gfortran -g -O0 -ffpe-trap=invalid -static where.F90
$ ./a.out 

Program received signal SIGFPE: Floating-point exception - erroneous arithmetic
operation.

Backtrace for this error:
#0  0x40FBFD in _gfortrani_show_backtrace at backtrace.c:260
#1  0x400676 in _gfortrani_backtrace_handler at compile_options.c:129
#2  0x42996F in raise
#3  0x4004C7 in MAIN__ at where.F90:10
Exception en point flottant

Tested with gfortran 4.6.1 and latest 4.7; it looks like SQRT(X) is evaluated
where L is false.

[Bug fortran/55214] Program fail to evaluate where clause

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55214

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-11-05
                 CC|                            |burnus at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-11-05 14:56:56 UTC ---
Confirmed - and not a regression as it also fails with GCC 4.1.

>From the C-like dump file (use -fdump-tree-original to create it):

For WHERE (L), one has:
            cond.3 = (logical(kind=1)) l[S.2 + -1];
            temp.0[count.1] = cond.3;

Which is then used in WHERE (SQRT(X)>0):

            cond.7 = __builtin_sqrtf (x[S.6 + -1]) > 0.0;
            mask.8 = temp.0[count.5];
            temp.4[count.5] = mask.8 && cond.7;

The proper way would be:
   mask.8 = temp.0[count.5];
   temp.4[count.5] = mask.8 ? __builtin_sqrtf (x[S.6 + -1]) > 0.0 : mask.8;

That is, the condition only gets evaluated if the outer mask is true.

[Bug fortran/55214] Program fail to evaluate where clause

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55214

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |anlauf at gmx dot de

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 64097 has been marked as a duplicate of this bug. ***