[Bug fortran/61910] New: undefined computation in trans-expr.c gfc_conv_cst_int_power

[Bug fortran/61910] New: undefined computation in trans-expr.c gfc_conv_cst_int_power

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

            Bug ID: 61910
           Summary: undefined computation in trans-expr.c
                    gfc_conv_cst_int_power
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zeccav at gmail dot com

Analyzing with sanitized gfortran the following line

j=i**(-huge(0_8)-1)

I get the following message:

../../gcc-4.9.1/gcc/fortran/trans-expr.c:2107:48: runtime error: 
negation of -9223372036854775808 cannot be represented in type 'long int'; 
cast to an unsigned type to negate this value to itself"

The offending line in trans-expr.c is

"n = (unsigned HOST_WIDE_INT) (m < 0 ? -m : m);"

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2014-08-02
     Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> Analyzing with sanitized gfortran the following line ...

I cannot reproduce it. Which options are you using? And does the message depend
on the value of i?

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

--- Comment #2 from Vittorio Zecca <zeccav at gmail dot com> ---
It appears not depending on i value, for i=1 or 2.

No explicit options used.
Of course I used options -fsanizitized=address -fsanitized=undefined
to generate gfortran.
I think it is either a gfortran or a sanitizer bug.

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.9.2

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Ok, I managed to whip up a complete testcase:

program test
  integer i
  integer j
  j=i**(-huge(0_8)-1)
end program test

on this I see
$ ./xgcc -B./ -c x.f90 
/home/polacek/src/gcc/gcc/fortran/trans-expr.c:2286:48: runtime error: negation
of -9223372036854775808 cannot be represented in type 'long int [3]'; cast to
an unsigned type to negate this value to itself

So confirmed.

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.2                       |4.9.3

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.2 has been released.

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.3 has been released.

[Bug fortran/61910] undefined computation in trans-expr.c gfc_conv_cst_int_power

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61910

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.3                       |4.9.4