* [Bug fortran/67531] FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test
2015-09-09 22:09 [Bug fortran/67531] New: FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test pthaugen at gcc dot gnu.org
@ 2015-09-10 21:31 ` pthaugen at gcc dot gnu.org
2015-09-10 21:45 ` fxcoudert at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pthaugen at gcc dot gnu.org @ 2015-09-10 21:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67531
--- Comment #2 from Pat Haugen <pthaugen at gcc dot gnu.org> ---
(In reply to Francois-Xavier Coudert from comment #1)
> Thanks for the report. So apparently, on powerpc64le-unknown-linux-gnu, long
> double division of 1.0L by 3.0L with rounding mode set to "down" is
> incorrect.
>
> Can you compile and run the following C test case?
>
> $ cat z.c
> #include <fenv.h>
> #include <stdio.h>
>
> int main (void)
> {
> long double x1, x2, x;
>
> fesetround (FE_UPWARD);
> x1 = 1;
> x = 3;
> x1 = x1 / x;
>
> fesetround (FE_DOWNWARD);
> x2 = 1;
> x = 3;
> x2 = x2 / x;
>
> printf ("%.40Lg\n", x1);
> printf ("%.40Lg\n", x2);
> }
> $ gcc z.c -lm && ./a.out
> 0.3333333333333333333423683514373792036167
> 0.3333333333333333333152632971252415927665
>
>
> Above is the result on x86_64-linux, so the outcome shouldn't be identical,
> but the two numbers output should not be equal.
pthaugen@genoa:~$ ~/install/gcc/trunk/bin/gcc z.c -lm && ./a.out
0.3333333333333333333333333333333353876586
0.3333333333333333333333333333333292246827
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug fortran/67531] FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test
2015-09-09 22:09 [Bug fortran/67531] New: FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test pthaugen at gcc dot gnu.org
2015-09-10 21:31 ` [Bug fortran/67531] " pthaugen at gcc dot gnu.org
@ 2015-09-10 21:45 ` fxcoudert at gcc dot gnu.org
2015-09-10 22:00 ` schwab@linux-m68k.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: fxcoudert at gcc dot gnu.org @ 2015-09-10 21:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67531
--- Comment #3 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
(In reply to Pat Haugen from comment #2)
> pthaugen@genoa:~$ ~/install/gcc/trunk/bin/gcc z.c -lm && ./a.out
> 0.3333333333333333333333333333333353876586
> 0.3333333333333333333333333333333292246827
How about with this? I'm trying to come as close as possible to the exact
sequence of fe.etround() calls as the Fortran front-end and runtime library
would end up performing…
#include <fenv.h>
#include <stdio.h>
int main (void)
{
int r;
long double x1, x2, x;
x1 = 1;
x = 3;
r = fegetround ();
fesetround (FE_UPWARD);
x1 = x1 / x;
fesetround (r);
x2 = 1;
x = 3;
r = fegetround ();
fesetround (FE_DOWNWARD);
x2 = x2 / x;
fesetround (r);
printf ("%.40Lg\n", x1);
printf ("%.40Lg\n", x2);
}
>From gcc-bugs-return-496923-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Thu Sep 10 21:52:57 2015
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From: "pangbw at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/59124] [4.9/5/6 Regression] Wrong warnings "array subscript is above array bounds"
Date: Thu, 10 Sep 2015 21:52:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idY124
--- Comment #19 from baoshan <pangbw at gmail dot com> ---
I did a little investigation to the code:
The warning occurs because tree_int_cst_lt (up_bound, up_sub) is true here:
else if (TREE_CODE (up_sub) == INTEGER_CST
&& (ignore_off_by_one
? (tree_int_cst_lt (up_bound, up_sub)
&& !tree_int_cst_equal (up_bound_p1, up_sub))
: (tree_int_cst_lt (up_bound, up_sub)
|| tree_int_cst_equal (up_bound_p1, up_sub))))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Array bound warning for ");
dump_generic_expr (MSG_NOTE, TDF_SLIM, ref);
fprintf (dump_file, "\n");
}
warning_at (location, OPT_Warray_bounds,
=> "array subscript is above array bounds");
TREE_NO_WARNING (ref) = 1;
}
I dumped the tree up_bound and up_sub:
(gdb) p debug_tree(up_bound)
<integer_cst 0x7ffff6acd3a8 type <integer_type 0x7ffff6c3d0a8 sizetype>
constant 5>
p debug_tree(up_sub)
<integer_cst 0x7ffff6ae92d0 type <integer_type 0x7ffff6c3d738 unsigned int>
constant 4294967291>
We can see the value of up_sub is represented as unsigned int value 4294967291
which is really weird to me, it suppose to be a int value -5 here.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug fortran/67531] FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test
2015-09-09 22:09 [Bug fortran/67531] New: FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test pthaugen at gcc dot gnu.org
2015-09-10 21:31 ` [Bug fortran/67531] " pthaugen at gcc dot gnu.org
2015-09-10 21:45 ` fxcoudert at gcc dot gnu.org
@ 2015-09-10 22:00 ` schwab@linux-m68k.org
2015-09-11 13:50 ` [Bug fortran/67531] No IEEE rounding support for powerpc long double type pthaugen at gcc dot gnu.org
2021-05-04 12:31 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: schwab@linux-m68k.org @ 2015-09-10 22:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67531
--- Comment #4 from Andreas Schwab <schwab@linux-m68k.org> ---
IBM long double does not support non-default rounding.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug fortran/67531] No IEEE rounding support for powerpc long double type
2015-09-09 22:09 [Bug fortran/67531] New: FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test pthaugen at gcc dot gnu.org
` (2 preceding siblings ...)
2015-09-10 22:00 ` schwab@linux-m68k.org
@ 2015-09-11 13:50 ` pthaugen at gcc dot gnu.org
2021-05-04 12:31 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pthaugen at gcc dot gnu.org @ 2015-09-11 13:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67531
--- Comment #5 from Pat Haugen <pthaugen at gcc dot gnu.org> ---
(In reply to Francois-Xavier Coudert from comment #3)
> How about with this? I'm trying to come as close as possible to the exact
> sequence of fe.etround() calls as the Fortran front-end and runtime library
> would end up performing…
>
>
> #include <fenv.h>
> #include <stdio.h>
>
> int main (void)
> {
> int r;
> long double x1, x2, x;
>
> x1 = 1;
> x = 3;
> r = fegetround ();
> fesetround (FE_UPWARD);
> x1 = x1 / x;
> fesetround (r);
>
> x2 = 1;
> x = 3;
> r = fegetround ();
> fesetround (FE_DOWNWARD);
> x2 = x2 / x;
> fesetround (r);
>
> printf ("%.40Lg\n", x1);
> printf ("%.40Lg\n", x2);
> }
pthaugen@genoa:~$ ~/install/gcc/trunk/bin/gcc junk.c -lm && ./a.out
0.3333333333333333333333333333333353876586
0.3333333333333333333333333333333292246828
>From gcc-bugs-return-496981-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Fri Sep 11 13:51:00 2015
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From: "olegendo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/59478] Optimize variable access via byte copy
Date: Fri, 11 Sep 2015 13:51:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idY478
--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to Oleg Endo from comment #0)
> This happens at least on SH with trunk rev 205905 (4.9).
> I'm not sure whether these are target specific or not.
>
> Accessing float values as integers can be done in various ways. One way is
> to do a byte copy...
>
> int float_as_int (float val)
> {
> char valbytes[sizeof (float)];
> __builtin_memcpy (valbytes, &val, sizeof (float));
>
> int result;
> __builtin_memcpy (&result, valbytes, sizeof (float));
>
> return result;
> }
>
> The above compiled with -m4-single -ml -O2 results in:
>
> add #-8,r15
> fmov.s fr5,@r15
> mov.l @r15,r0
> rts
> add #8,r15
>
> which is not so bad actually, but could be done better by utilizing the fpul
> register, as it is done when using the union approach:
This case got better. It now produces the expected sequence:
flds fr5,fpul
rts
sts fpul,r0
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug fortran/67531] No IEEE rounding support for powerpc long double type
2015-09-09 22:09 [Bug fortran/67531] New: FAIL: gfortran.dg/ieee/large_2.f90 -O0 execution test pthaugen at gcc dot gnu.org
` (3 preceding siblings ...)
2015-09-11 13:50 ` [Bug fortran/67531] No IEEE rounding support for powerpc long double type pthaugen at gcc dot gnu.org
@ 2021-05-04 12:31 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-05-04 12:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67531
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
^ permalink raw reply [flat|nested] 6+ messages in thread