Bug 2574 - Incorrect return from float log10 (0X1.118C6318C6319P+0)
Summary: Incorrect return from float log10 (0X1.118C6318C6319P+0)
Status: RESOLVED INVALID
Alias: None
Product: glibc
Classification: Unclassified
Component: math (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Ulrich Drepper
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2006-04-14 19:21 UTC by H.J. Lu
Modified: 2019-04-10 09:07 UTC (History)
1 user (show)

See Also:
Host: x86_64-unknown-linux-gnu
Target: x86_64-unknown-linux-gnu
Build: x86_64-unknown-linux-gnu
Last reconfirmed:
fweimer: security-

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Description H.J. Lu 2006-04-14 19:21:05 UTC 
Failure: Test: log10 (0X1.118C6318C6319P+0) == 0X1.D7C3996E6179DP-6
Result:
 is:          2.87942159920930862427e-02   0x1.d7c3b200000000000000p-6
 should be:   2.87941936403512954712e-02   0x1.d7c39a00000000000000p-6
 difference:  2.23517417907714843750e-08   0x1.80000000000000000000p-26
 ulp       :  12.0000
 max.ulp   :  0.0000
Comment 1 Ulrich Drepper 2006-04-16 02:45:21 UTC 
libm bugs remain suspended until somebody comes up with a patch.
Comment 2 Joseph Myers 2012-02-26 17:26:48 UTC 
When the argument is rounded to float (0X1.118C64P+0), the correctly rounded result becomes 0X1.D7C3B0P-6, so the error is 1ulp not 12ulp, and since there's already a test of log10f in the testsuite with a 2ulp error recorded in libm-test-ulps for x86_64, I don't think it's useful to add this test as well or keep a bug open for this 1ulp error.