Re: [Valgrind-users] mysterious failures when using valgrind

[Vasily G. <vas...@gm...>]

It may be helpful to test Valgrind's trunk from svn repository, at first.

On Tue, Sep 24, 2013 at 7:55 PM, John Reiser <jr...@bi...> wrote:
>> __float128 exp10(__float128);
>>
>> When that routine is called with a negative argument, the return value
>> changes when I run the code through valgrind, e.g.
>>
>> -20 3fbc79ca10c9242235d511e976394d7a (without valgrind)
>> -20 3fbc79ca10c9240e12445f2000000000 (with valgrind)
>>
>> The -20 is the argument for exp10() and was obviously converted to
>> __float128, and the return value is printed here in hex format.
>> Initially I thought that the lowest 64 bits were mangled, but from this
>> example you can see that it is a bit more (the lowest 70 bits differ).
>
> This is a bug in memcheck.  Please file a bug report.
> Construct a short test case program (15 lines or so)
> which reproduces the output above.  Then go to the main page
> http://www.valgrind.org/ , click on the Bug Reports link
> (left column under Contact), describe the problem (much as above),
> copy+paste the output, and attach the test case program.
> Please also include the versions of valgrind, compiler, C/math library,
> and operating system; and kind of hardware.
> Thank you.
>
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-- 
Best Regards,
Vasily