Re: [gentoo-amd64] Possible Math Problem - Request For Verification [Solved]

[Frank Peters]

On Sat, 25 Jun 2011 13:41:11 -0400
Frank Peters <frank.peters@×××××××.net> wrote:

>
> /tmp/fp-test-results/clib_DP.output: ucbtest UCBFAIL in cabsd at line 701 for double
>

The culprit seems to be GCC optimization.  If I run the test with either "-O0"
or "-O1" flags I can eliminate the cabsd failure.  Using "-O2" or "-O3" will
result in the cabsd error.

However, I've used "-O2" previously and had no problems with this test.  Possibly,
some of these new LTO and GRAPHITE capabilities of GCC are to blame, even though
I do not compile the ucbtest with either LTO or GRAPHITE enabled.  But GCC has itself
been compiled using LTO and GRAPHITE.

Anyway, thanks for all who actually ran the test on their machines.  I was
thinking of filing bug reports with GLIBC and GCC and that would have turned
out to be foolish.  I did check the Changelogs for GLIBC and there doesn't seem
to have been any modification of the cabs() code over the last several versions.

Frank Peters