[Bug fortran/45425] Bounds check applied before MASK of WHERE construct

2021-12-17 Thread pinskia at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425

Andrew Pinski  changed:

   What|Removed |Added

   Keywords||diagnostic
   Last reconfirmed|2010-08-28 19:51:18 |2021-12-17
  Known to fail||

--- Comment #4 from Andrew Pinski  ---
We also now get a warning since GCC 8 too:
/app/example.f90:10:10:

8 | do i = 2, 2
  |   2
9 |   where (mask)
   10 | A = b(i)
  |  1
Warning: Array reference at (1) out of bounds (2 > 1) in loop beginning at (2)
/app/example.f90:10:10:

8 | do i = 2, 2
  |   2
9 |   where (mask)
   10 | A = b(i)
  |  1
Warning: Array reference at (1) out of bounds (2 > 1) in loop beginning at (2)

[Bug fortran/45425] Bounds check applied before MASK of WHERE construct

2010-08-28 Thread burnus at gcc dot gnu dot org 


--- Comment #2 from burnus at gcc dot gnu dot org  2010-08-28 15:40 ---
The error message is generated in
  gfc_conv_array_ref
it's called via gfc_trans_where_3 - gfc_conv_loop_setup -
gfc_add_loop_ss_code - gfc_conv_variable

Thus, the condition (mask) ends up at
  gfc_add_ss_to_loop (loop, css);
and the bounds check is added via
  gfc_conv_loop_setup (loop, tdst-where);

Thus, it ends up at loop-pre which comes before the actual loop.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425

[Bug fortran/45425] Bounds check applied before MASK of WHERE construct

2010-08-28 Thread mikael at gcc dot gnu dot org 


--- Comment #3 from mikael at gcc dot gnu dot org  2010-08-28 17:42 ---
Ouch!
We need some sort of lazy evaluation.
Like (pseudo-code)

bool scalar_ever_evaluated = false;
whatever_type scalar_value;

while(1)
  {
/* loop handling stuff */

if (scalar_ever_evaluated)
  {
scalar_value = whatever complicated expression;
scalar_ever_evaluated = true;
  }

/* normal code using scalar_value */
  }


We have to move back se-pre into se-expr so that it is not moved outside the
loop. Or move it outside the loop conditionally and conditionally add se-pre
inside the loop while evaluating the scalar. 

BTW I thought there was already some where-specific code generation for scalar
values. 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425

[Bug fortran/45425] Bounds check applied before MASK of WHERE construct

2010-08-28 Thread tkoenig at gcc dot gnu dot org 


-- 

tkoenig at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2010-08-28 19:51:18
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425

[Bug fortran/45425] Bounds check applied before MASK of WHERE construct

2010-08-27 Thread burnus at gcc dot gnu dot org 


--- Comment #1 from burnus at gcc dot gnu dot org  2010-08-27 11:58 ---
Confirm, the bounds checks are misplaces. Simplified test case:

implicit none
integer :: A(1), i,b(1)
logical :: mask(1)

mask = .false.
b = 5
do i = 2, 2
  where (mask)
A = b(i)
  end where
end do
end



If one looks at the dump of the internal representation (-fdump-tree-original)
one sees that WHERE itself is properly handled - only the bounds check is
outside of the WHERE loop and thus outside of the MASK:

  if (__builtin_expect (i = 0, 0))
_gfortran_runtime_error_at (...);
[...]
  S.1 = 1;
  while (1)
{
  if (S.1  1) goto L.4;
  if (mask[S.1 + -1])
{
  a[S.1 + -1] = b[i + -1];
}
  S.1 = S.1 + 1;
}


-- 

burnus at gcc dot gnu dot org changed:

   What|Removed |Added

OtherBugsDependingO||27766
  nThis||
   Keywords||wrong-code
  Known to fail||4.1.2 4.6.0
Summary|where mask not applied  |Bounds check applied before
   |before where clause |MASK of WHERE construct
   |evaluated   |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45425