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* [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939)
@ 2011-09-25 20:07 zeccav at gmail dot com
2011-09-25 22:13 ` [Bug fortran/50514] " kargl at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: zeccav at gmail dot com @ 2011-09-25 20:07 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
Bug #: 50514
Summary: gfortran should check ISHFT & ISHFTC aruments
(r178939)
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: fortran
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: zeccav@gmail.com
! gfortran should check ISHFT & ISHFTC aruments (r178939)
! gfortran should not accept SHIFT>BIT_SIZE(I)
print *,ishft(I=m,SHIFT=640)
print *,ishftc(I=m,SHIFT=640)
! abs(SHIFT) must be <= SIZE
print *,ishftc(I=m,SHIFT=1,SIZE=0)
end
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/50514] gfortran should check ISHFT & ISHFTC aruments (r178939)
2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
@ 2011-09-25 22:13 ` kargl at gcc dot gnu.org
2011-09-28 10:43 ` zeccav at gmail dot com
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: kargl at gcc dot gnu.org @ 2011-09-25 22:13 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kargl at gcc dot gnu.org
--- Comment #1 from kargl at gcc dot gnu.org 2011-09-25 22:05:14 UTC ---
Technically, it the programmer that should check the arguments.
The prohibitions in the Fortran Standard are placed on the
programmer not the Fortran processor (ie., the compiler).
Adding the check into
do i = 1,1000000
do j = 1, 1000000
do k = 1, 1000000
! Some stuff here to compute k and n < bit_size(k)
m = ishft(k,n) ! for some k, n
! More stuff here to use m
end do
end do
end do
seems like useless overhead.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/50514] gfortran should check ISHFT & ISHFTC aruments (r178939)
2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
2011-09-25 22:13 ` [Bug fortran/50514] " kargl at gcc dot gnu.org
@ 2011-09-28 10:43 ` zeccav at gmail dot com
2011-09-28 20:03 ` sgk at troutmask dot apl.washington.edu
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: zeccav at gmail dot com @ 2011-09-28 10:43 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
--- Comment #2 from Vittorio Zecca <zeccav at gmail dot com> 2011-09-28 09:20:40 UTC ---
I meant checking static expressions at compilation time, as in my example.
This has no cost at run time.
You proposed a run time check that still should be done if requested with a
kind of -fcheck option.
By the way, gfortran is already checking consistency of static arguments to
intrinsic functions, it is that just these one are left unchecked.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/50514] gfortran should check ISHFT & ISHFTC aruments (r178939)
2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
2011-09-25 22:13 ` [Bug fortran/50514] " kargl at gcc dot gnu.org
2011-09-28 10:43 ` zeccav at gmail dot com
@ 2011-09-28 20:03 ` sgk at troutmask dot apl.washington.edu
2011-09-29 7:56 ` zeccav at gmail dot com
2011-10-20 18:12 ` kargl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: sgk at troutmask dot apl.washington.edu @ 2011-09-28 20:03 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
--- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> 2011-09-28 19:45:48 UTC ---
On Wed, Sep 28, 2011 at 09:20:40AM +0000, zeccav at gmail dot com wrote:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
>
> --- Comment #2 from Vittorio Zecca <zeccav at gmail dot com> 2011-09-28 09:20:40 UTC ---
> I meant checking static expressions at compilation time, as in my example.
> This has no cost at run time.
I know want you meant.
> You proposed a run time check that still should be done if requested with a
> kind of -fcheck option.
I disagree.
> By the way, gfortran is already checking consistency of static arguments to
> intrinsic functions, it is that just these one are left unchecked.
Yes, I know. I wrote some of the code.
Index: testsuite/gfortran.dg/ishft_3.f90
===================================================================
--- testsuite/gfortran.dg/ishft_3.f90 (revision 179208)
+++ testsuite/gfortran.dg/ishft_3.f90 (working copy)
@@ -1,11 +1,38 @@
! { dg-do compile }
+! PR fortran/50514
program ishft_3
- integer i, j
- write(*,*) ishftc( 3, 2, 3 )
- write(*,*) ishftc( 3, 2, i )
- write(*,*) ishftc( 3, i, j )
- write(*,*) ishftc( 3, 128 ) ! { dg-error "exceeds BIT_SIZE of first" }
- write(*,*) ishftc( 3, 0, 128 ) ! { dg-error "exceeds BIT_SIZE of first" }
- write(*,*) ishftc( 3, 0, 0 ) ! { dg-error "Invalid third argument" }
- write(*,*) ishftc( 3, 3, 2 ) ! { dg-error "exceeds third argument" }
+
+ implicit none
+
+ integer j, m
+
+ m = 42
+ !
+ ! These should compile.
+ !
+ j = ishft(m, 16)
+ j = ishft(m, -16)
+ j = ishftc(m, 16)
+ j = ishftc(m, -16)
+ !
+ ! These should issue an error.
+ !
+ j = ishft(m, 640) ! { dg-error "absolute value of SHIFT" }
+ j = ishftc(m, 640) ! { dg-error "absolute value of SHIFT" }
+ j = ishft(m, -640) ! { dg-error "absolute value of SHIFT" }
+ j = ishftc(m, -640) ! { dg-error "absolute value of SHIFT" }
+
+ ! abs(SHIFT) must be <= SIZE
+
+ j = ishftc(m, 1, 2)
+ j = ishftc(m, 1, 2)
+ j = ishftc(m, -1, 2)
+ j = ishftc(m, -1, 2)
+
+ j = ishftc(m, 10, 2)! { dg-error "absolute value of SHIFT" }
+ j = ishftc(m, 10, 2)! { dg-error "absolute value of SHIFT" }
+ j = ishftc(m, -10, 2)! { dg-error "absolute value of SHIFT" }
+ j = ishftc(m, -10, 2)! { dg-error "absolute value of SHIFT" }
+
+ j = ishftc(m, 1, -2) ! { dg-error "must be positive" }
end program
Index: fortran/check.c
===================================================================
--- fortran/check.c (revision 179208)
+++ fortran/check.c (working copy)
@@ -318,6 +318,22 @@ less_than_bitsize1 (const char *arg1, gf
{
gfc_extract_int (expr2, &i2);
i3 = gfc_validate_kind (BT_INTEGER, expr1->ts.kind, false);
+
+ /* For ISHFT[C], |shift| <= bit_size(i). */
+ if (strncmp (arg2, "ISHFT", 5) == 0)
+ {
+ if (i2 < 0)
+ i2 = -i2;
+
+ if (i2 > gfc_integer_kinds[i3].bit_size)
+ {
+ gfc_error ("The absolute value of SHIFT at %L must be less "
+ "than or equal to BIT_SIZE('%s')",
+ &expr2->where, arg1);
+ return FAILURE;
+ }
+ }
+
if (or_equal)
{
if (i2 > gfc_integer_kinds[i3].bit_size)
@@ -1961,6 +1977,9 @@ gfc_check_ishft (gfc_expr *i, gfc_expr *
|| type_check (shift, 1, BT_INTEGER) == FAILURE)
return FAILURE;
+ if (less_than_bitsize1 ("I", i, "ISHFT", shift, true) == FAILURE)
+ return FAILURE;
+
return SUCCESS;
}
@@ -1972,7 +1991,35 @@ gfc_check_ishftc (gfc_expr *i, gfc_expr
|| type_check (shift, 1, BT_INTEGER) == FAILURE)
return FAILURE;
- if (size != NULL && type_check (size, 2, BT_INTEGER) == FAILURE)
+ if (size != NULL)
+ {
+ int i2, i3;
+
+ if (type_check (size, 2, BT_INTEGER) == FAILURE)
+ return FAILURE;
+
+ if (less_than_bitsize1 ("I", i, "SIZE", size, true) == FAILURE)
+ return FAILURE;
+
+ gfc_extract_int (size, &i3);
+ if (i3 <= 0)
+ {
+ gfc_error ("SIZE at %L must be positive", &size->where);
+ return FAILURE;
+ }
+
+ gfc_extract_int (shift, &i2);
+ if (i2 < 0)
+ i2 = -i2;
+
+ if (i2 > i3)
+ {
+ gfc_error ("The absolute value of SHIFT at %L must be less than "
+ "or equal to SIZE at %L", &shift->where, &size->where);
+ return FAILURE;
+ }
+ }
+ else if (less_than_bitsize1 ("I", i, "ISHFTC", shift, true) == FAILURE)
return FAILURE;
return SUCCESS;
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/50514] gfortran should check ISHFT & ISHFTC aruments (r178939)
2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
` (2 preceding siblings ...)
2011-09-28 20:03 ` sgk at troutmask dot apl.washington.edu
@ 2011-09-29 7:56 ` zeccav at gmail dot com
2011-10-20 18:12 ` kargl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: zeccav at gmail dot com @ 2011-09-29 7:56 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
--- Comment #4 from Vittorio Zecca <zeccav at gmail dot com> 2011-09-29 06:58:24 UTC ---
About run time checking: I believe the bit size of k is known at compile time,
and the overhead to check n against it is negligible as compared to computing
ishft itself and maybe n.
Of course when I am asking -fcheck I am prepared to slower execution, but it
may well pay off, if I find a bug. I believe programmer (debugging) time is now
costlier than hardware time.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/50514] gfortran should check ISHFT & ISHFTC aruments (r178939)
2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
` (3 preceding siblings ...)
2011-09-29 7:56 ` zeccav at gmail dot com
@ 2011-10-20 18:12 ` kargl at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: kargl at gcc dot gnu.org @ 2011-10-20 18:12 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50514
kargl at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
--- Comment #5 from kargl at gcc dot gnu.org 2011-10-20 18:11:33 UTC ---
Fixed on trunk for static checking. Runtime checking is not
going to happen due to the overhead.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-10-20 18:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2011-09-25 20:07 [Bug fortran/50514] New: gfortran should check ISHFT & ISHFTC aruments (r178939) zeccav at gmail dot com
2011-09-25 22:13 ` [Bug fortran/50514] " kargl at gcc dot gnu.org
2011-09-28 10:43 ` zeccav at gmail dot com
2011-09-28 20:03 ` sgk at troutmask dot apl.washington.edu
2011-09-29 7:56 ` zeccav at gmail dot com
2011-10-20 18:12 ` kargl at gcc dot gnu.org
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