Control: tags -1 upstream
Control: forwarded -1 https://bugs.kde.org/show_bug.cgi?id=421262
Control: retitle -1 valgrind causes miscalculation on long double
On 2018-02-12 03:04:30 +0100, Vincent Lefevre wrote:
> valgrind causes miscalculation on the following program:
>
> ----------------------------------------
> #include <stdio.h>
>
> int main (void)
> {
> volatile union {
> long double d;
> unsigned long i[2];
> } u;
>
> u.i[0] = 1;
> u.i[1] = 0;
> printf ("%La\n", u.d);
>
> return 0;
> }
> ----------------------------------------
Note that the above value is a subnormal.
This appears to be the same kind of problem as mentioned in a bug
reported upstream last month:
https://bugs.kde.org/show_bug.cgi?id=421262
As said, the cause is that valgrind converts the value to
double precision.
--
Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
