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* [Bug c++/97086] New: aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0
@ 2020-09-17 13:01 mfarazma.ext at gmail dot com
2020-09-17 16:32 ` [Bug target/97086] " pinskia at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: mfarazma.ext at gmail dot com @ 2020-09-17 13:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97086
Bug ID: 97086
Summary: aix: ceilf and truncf do not preserve the sign bit
when output is rounded to 0
Product: gcc
Version: 8.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: mfarazma.ext at gmail dot com
Target Milestone: ---
Test program:
#include <iostream>
#include <math.h>
int main(){
float input = -0.1;
printf("%f\n", ceilf(-0.1)); // -0.000000 , correct
printf("%f\n", ceilf(input)); // 0.000000 , wrong
return 0;
}
Compile with:
g++ test.cc
./a.out
"ceilf" does not preserve the sign bit when its input is passed by value and
the output is rounded to 0.
The same happens when using "truncf".
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/97086] aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 2020-09-17 13:01 [Bug c++/97086] New: aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 mfarazma.ext at gmail dot com @ 2020-09-17 16:32 ` pinskia at gcc dot gnu.org 2020-10-13 15:30 ` mfarazma.ext at gmail dot com 2020-10-13 15:39 ` mfarazma.ext at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2020-09-17 16:32 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97086 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Component|c++ |target --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This might NOT be a GCC issue but rather an issue with the libc that AIX has. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/97086] aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 2020-09-17 13:01 [Bug c++/97086] New: aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 mfarazma.ext at gmail dot com 2020-09-17 16:32 ` [Bug target/97086] " pinskia at gcc dot gnu.org @ 2020-10-13 15:30 ` mfarazma.ext at gmail dot com 2020-10-13 15:39 ` mfarazma.ext at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: mfarazma.ext at gmail dot com @ 2020-10-13 15:30 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97086 --- Comment #2 from m farazma <mfarazma.ext at gmail dot com> --- Wanted to point out the same happens when using "nearbyint": ``` #include <iostream> #include <math.h> int main(){ std::cout << nearbyintf(-0) << std::endl; return 0; } ``` expected: -0 actual: 0 https://en.cppreference.com/w/c/numeric/math/nearbyint Above url clearly mentions "If arg is ±0, it is returned, unmodified". ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/97086] aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 2020-09-17 13:01 [Bug c++/97086] New: aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 mfarazma.ext at gmail dot com 2020-09-17 16:32 ` [Bug target/97086] " pinskia at gcc dot gnu.org 2020-10-13 15:30 ` mfarazma.ext at gmail dot com @ 2020-10-13 15:39 ` mfarazma.ext at gmail dot com 2 siblings, 0 replies; 4+ messages in thread From: mfarazma.ext at gmail dot com @ 2020-10-13 15:39 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97086 --- Comment #3 from m farazma <mfarazma.ext at gmail dot com> --- Sorry the above example needs to be changed to this in order to reproduce the bug: ``` #include <iostream> #include <math.h> int main(){ float a = -0.0; std::cout << nearbyintf(a) << std::endl; return 0; } ``` ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-10-13 15:39 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-09-17 13:01 [Bug c++/97086] New: aix: ceilf and truncf do not preserve the sign bit when output is rounded to 0 mfarazma.ext at gmail dot com 2020-09-17 16:32 ` [Bug target/97086] " pinskia at gcc dot gnu.org 2020-10-13 15:30 ` mfarazma.ext at gmail dot com 2020-10-13 15:39 ` mfarazma.ext at gmail dot com
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