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From: "ro at CeBiTec dot Uni-Bielefeld.DE" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/98384] [11 Regression] new test case
 20_util/to_chars/long_double.cc in r11-6249 fails on powerpc64 BE
Date: Fri, 08 Jan 2021 09:30:23 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98384

--- Comment #7 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot U=
ni-Bielefeld.DE> ---
> --- Comment #6 from Patrick Palka <ppalka at gcc dot gnu.org> ---
[...]
> Thanks for testing!  Hmm, that execute failure is surprising.  I wonder j=
ust
> how much we're diverging from the output of printf here.  If possible, co=
uld
> you let me know the value of the locals 'to_chars_buffer', 'printf_buffer=
',
> 'precision' and 'testcase' (ideally in hex form) at the point of the asse=
rtion
> failure?

I'm seeing exactly the same failure mode on Solaris, both sparc and x86:
32-bit compilation PASSes, execution XFAILed, 64-bit compilation PASSes,
too, but execution FAILs with the same assertion failure.

Here's what gdb prints for those variables (with the test compiled with
-g3 -O0 where the assertion still fails):

(gdb) p to_chars_buffer
$1 =3D "f.", 'f' <repeats 14 times>, "ep+5380", '\000' <repeats 1000 times>
(gdb) p printf_buffer
$2 =3D "0x1.", 'f' <repeats 15 times>, "cp+5383", '\000' <repeats 997 times>
(gdb) p precision
No symbol "precision" in current context.
(gdb) p testcase
$3 =3D 5.56540347525605847154e+1620
(gdb) p/x testcase
$5 =3D 0x7fffffffffffffff=