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* [Bug fortran/67614] New: ICE on using arithmetic if with null
@ 2015-09-17 18:03 gerhard.steinmetz.fortran@t-online.de
2015-09-17 18:04 ` [Bug fortran/67614] " gerhard.steinmetz.fortran@t-online.de
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: gerhard.steinmetz.fortran@t-online.de @ 2015-09-17 18:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
Bug ID: 67614
Summary: ICE on using arithmetic if with null
Product: gcc
Version: 5.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: gerhard.steinmetz.fortran@t-online.de
Target Milestone: ---
Some cases with oldstyle arithmetic if in combination with null
instead of a scalar-numeric-expr :
$ cat z1.f90
program p
integer, allocatable :: z
if ( null(z) ) 1, 2, 3
1 stop 1
2 stop 2
3 stop 3
end
$ gfortran -g -O0 -Wall -fcheck=all -fno-frontend-optimize z1.f90
internal compiler error: in gfc_build_const, at fortran/trans-const.c:76
$ cat z2.f90
program p
integer, pointer :: z
if ( null(z) ) 1, 2, 3
1 stop 1
2 stop 2
3 stop 3
end
$ gfortran z2.f90
internal compiler error: in gfc_build_const, at fortran/trans-const.c:76
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
@ 2015-09-17 18:04 ` gerhard.steinmetz.fortran@t-online.de
2015-09-17 23:03 ` dominiq at lps dot ens.fr
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: gerhard.steinmetz.fortran@t-online.de @ 2015-09-17 18:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
--- Comment #1 from Gerhard Steinmetz <gerhard.steinmetz.fortran@t-online.de> ---
$ cat z4.f90
program p
integer, pointer :: z => null()
if ( z ) 1, 2, 3
1 stop 1
2 stop 2
3 stop 3
end
$ gfortran -g -O0 -Wall -fcheck=all -fno-frontend-optimize z4.f90
$ a.out
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
2015-09-17 18:04 ` [Bug fortran/67614] " gerhard.steinmetz.fortran@t-online.de
@ 2015-09-17 23:03 ` dominiq at lps dot ens.fr
2015-09-23 23:06 ` kargl at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: dominiq at lps dot ens.fr @ 2015-09-17 23:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
Dominique d'Humieres <dominiq at lps dot ens.fr> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-09-17
Ever confirmed|0 |1
--- Comment #2 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Confirmed from 4.8 up to trunk (6.0).
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
2015-09-17 18:04 ` [Bug fortran/67614] " gerhard.steinmetz.fortran@t-online.de
2015-09-17 23:03 ` dominiq at lps dot ens.fr
@ 2015-09-23 23:06 ` kargl at gcc dot gnu.org
2015-09-24 14:38 ` gerhard.steinmetz.fortran@t-online.de
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: kargl at gcc dot gnu.org @ 2015-09-23 23:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kargl at gcc dot gnu.org
--- Comment #3 from kargl at gcc dot gnu.org ---
I'm inclined to close this PR as WONTFIX. The F2008 in
2.4.8 states: "A pointer that is not associated shall
not be referenced or defined." This is not a numbered
constraint and so a Fortran processor is not required
to report an error. It is the programmer's responsibility
to ensure that a referenced pointer is associated.
In addition, consider the code
program y1
real, pointer :: a
real, target :: b
b = 42
a => b
call foo(a)
a => null()
call foo(a)
contains
subroutine foo(x)
real, pointer :: x
if (2*x+1) 10, 20, 30
10 print *, 'a'; goto 40
20 print *, 'b'; goto 40
30 print *, 'c'; goto 40
40 continue
end subroutine
end program y1
The evaluation of the scalar-numeric-expr in the
arithmetic-if would requires a runtime check that
x is in fact an associated pointer. This could
be rather costly and prevent possible optimizations
if gfortran tried to always ensure any reference
to a pointer is properly associated.
It is the responsibility of the programmer to
write
if (associated(x) then
if (2*x+1) 10, 20, 30
...
end if
Of course, if someone wants to add an -fcheck=pointer-status
option, then problems in this PR can be at least checked.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
` (2 preceding siblings ...)
2015-09-23 23:06 ` kargl at gcc dot gnu.org
@ 2015-09-24 14:38 ` gerhard.steinmetz.fortran@t-online.de
2015-09-24 14:40 ` gerhard.steinmetz.fortran@t-online.de
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: gerhard.steinmetz.fortran@t-online.de @ 2015-09-24 14:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
--- Comment #4 from Gerhard Steinmetz <gerhard.steinmetz.fortran@t-online.de> ---
In general, a future extension to check pointer status
looks promising (at compile time and runtime).
With a tiny and simple source the problem is clear and
obvious, but for large and complex codes often not.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
` (3 preceding siblings ...)
2015-09-24 14:38 ` gerhard.steinmetz.fortran@t-online.de
@ 2015-09-24 14:40 ` gerhard.steinmetz.fortran@t-online.de
2015-09-25 22:31 ` kargl at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: gerhard.steinmetz.fortran@t-online.de @ 2015-09-24 14:40 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
--- Comment #5 from Gerhard Steinmetz <gerhard.steinmetz.fortran@t-online.de> ---
For comparison, a logical if (assumes scalar-logical-expr
instead of scalar-numeric-expr in arithmetic if) "avoids"
an ICE. Analogous examples :
$ cat y1.f90
program p
logical, allocatable :: z
if ( null(z) ) print *, 'a'
end
$ cat y2.f90
program p
logical, pointer :: z
if ( null(z) ) print *, 'a'
end
$ cat y7.f90
program p
logical, allocatable :: z
if ( null(z) ) then
print *, 'a'
else
print *, 'not a'
end if
end
$ gfortran -g -O0 -Wall -fcheck=all -fno-frontend-optimize y7.f90
$ a.out
not a
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
` (4 preceding siblings ...)
2015-09-24 14:40 ` gerhard.steinmetz.fortran@t-online.de
@ 2015-09-25 22:31 ` kargl at gcc dot gnu.org
2015-09-25 22:59 ` kargl at gcc dot gnu.org
2015-09-25 23:03 ` kargl at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: kargl at gcc dot gnu.org @ 2015-09-25 22:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
--- Comment #6 from kargl at gcc dot gnu.org ---
Author: kargl
Date: Fri Sep 25 22:30:26 2015
New Revision: 228156
URL: https://gcc.gnu.org/viewcvs?rev=228156&root=gcc&view=rev
Log:
2015-09-25 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/67614
* resolve.c (gfc_resolve_code): Prevent ICE for invalid EXPR_NULL.
2015-09-25 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/67614
* gfortran.dg/pr67614.f90: New test.
Added:
trunk/gcc/testsuite/gfortran.dg/pr67614.f90
Modified:
trunk/gcc/fortran/ChangeLog
trunk/gcc/fortran/resolve.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
` (5 preceding siblings ...)
2015-09-25 22:31 ` kargl at gcc dot gnu.org
@ 2015-09-25 22:59 ` kargl at gcc dot gnu.org
2015-09-25 23:03 ` kargl at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: kargl at gcc dot gnu.org @ 2015-09-25 22:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
--- Comment #7 from kargl at gcc dot gnu.org ---
Author: kargl
Date: Fri Sep 25 22:59:15 2015
New Revision: 228158
URL: https://gcc.gnu.org/viewcvs?rev=228158&root=gcc&view=rev
Log:
2015-09-25 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/67614
* resolve.c (gfc_resolve_code): Prevent ICE for invalid EXPR_NULL.
2015-09-25 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/67614
* gfortran.dg/pr67614.f90: New test.
Added:
branches/gcc-5-branch/gcc/testsuite/gfortran.dg/pr67614.f90
Modified:
branches/gcc-5-branch/gcc/fortran/ChangeLog
branches/gcc-5-branch/gcc/fortran/resolve.c
branches/gcc-5-branch/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug fortran/67614] ICE on using arithmetic if with null
2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
` (6 preceding siblings ...)
2015-09-25 22:59 ` kargl at gcc dot gnu.org
@ 2015-09-25 23:03 ` kargl at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: kargl at gcc dot gnu.org @ 2015-09-25 23:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67614
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
Assignee|unassigned at gcc dot gnu.org |kargl at gcc dot gnu.org
Target Milestone|--- |5.3
--- Comment #8 from kargl at gcc dot gnu.org ---
Fixed on trunk and 5-branch. Thanks for bug report
and convincing me to look at it again.
^ permalink raw reply [flat|nested] 9+ messages in thread
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2015-09-17 18:03 [Bug fortran/67614] New: ICE on using arithmetic if with null gerhard.steinmetz.fortran@t-online.de
2015-09-17 18:04 ` [Bug fortran/67614] " gerhard.steinmetz.fortran@t-online.de
2015-09-17 23:03 ` dominiq at lps dot ens.fr
2015-09-23 23:06 ` kargl at gcc dot gnu.org
2015-09-24 14:38 ` gerhard.steinmetz.fortran@t-online.de
2015-09-24 14:40 ` gerhard.steinmetz.fortran@t-online.de
2015-09-25 22:31 ` kargl at gcc dot gnu.org
2015-09-25 22:59 ` kargl at gcc dot gnu.org
2015-09-25 23:03 ` kargl at gcc dot gnu.org
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