[Bug math/14803] New: Different ULPs depending on size of long int in GCC

["hjl.tools at gmail dot com" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=14803

             Bug #: 14803
           Summary: Different ULPs depending on size of long int in GCC
           Product: glibc
           Version: 2.17
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
        AssignedTo: unassigned@sourceware.org
        ReportedBy: hjl.tools@gmail.com
    Classification: Unclassified


Since GCC encodes float-pointing constants slightly different,
depend on size of long int:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55145

x86-64 glibc built by x32 GCC has

[hjl@gnu-tools-1 glibc-test]$ cat
/export/build/gnu/glibc-test/build-x86_64-linx/math/test-ildoubl.out
testing long double (inline functions)
Failure: Test: asin (0x0.ffffffp0) ==
1.5704510598101804156437184421571127056013
Result:
 is:          1.57045105981018041572e+00   0xc.9048a52ed37c86000000p-3
 should be:   1.57045105981018041561e+00   0xc.9048a52ed37c85f00000p-3
 difference:  1.08420217248550443401e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000
Failure: Test: asin (-0x0.ffffffp0) ==
-1.5704510598101804156437184421571127056013
Result:
 is:         -1.57045105981018041572e+00  -0xc.9048a52ed37c86000000p-3
 should be:  -1.57045105981018041561e+00  -0xc.9048a52ed37c85f00000p-3
 difference:  1.08420217248550443401e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000
Failure: Test: asin (0x0.ffffffff8p0) ==
1.5707810680058339712015850710748035974710
Result:
 is:          1.57078106800583397126e+00   0xc.90f5aa22168bce000000p-3
 should be:   1.57078106800583397115e+00   0xc.90f5aa22168bcdf00000p-3
 difference:  1.08420217248550443401e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000
Failure: Test: asin (-0x0.ffffffff8p0) ==
-1.5707810680058339712015850710748035974710
Result:
 is:         -1.57078106800583397126e+00  -0xc.90f5aa22168bce000000p-3
 should be:  -1.57078106800583397115e+00  -0xc.90f5aa22168bcdf00000p-3
 difference:  1.08420217248550443401e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000
Failure: Test: asin_downward (-1.0) == -pi/2
Result:
 is:         -1.57079632679489661937e+00  -0xc.90fdaa22168c23600000p-3
 should be:  -1.57079632679489661926e+00  -0xc.90fdaa22168c23500000p-3
 difference:  1.08420217248550443400e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000
Failure: Test: asin_upward (1.0) == pi/2
Result:
 is:          1.57079632679489661937e+00   0xc.90fdaa22168c23600000p-3
 should be:   1.57079632679489661926e+00   0xc.90fdaa22168c23500000p-3
 difference:  1.08420217248550443401e-19   0x8.00000000000000000000p-66
 ulp       :  1.0000
 max.ulp   :  0.0000

Test suite completed:
  5855 test cases plus 5008 tests for exception flags executed.
  6 errors occurred.
[hjl@gnu-tools-1 glibc-test]$ 

comparing against x86-64 glibc built with x86-64 GCC.

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