alpha: cpow math testsuite failures with GCC 9

[Aurelien Jarno]

On 2019-09-02 08:32, Florian Weimer wrote:
> * Aurelien Jarno:
> 
> > Here is the detailed failure for math/test-double-cpow:
> >
> > | FAIL: math/test-double-cpow
> > | original exit status 1
> > | testing double (without inline functions)
> > | Failure: Test: Real part of: cpow_downward (0x2p+0 + +0 i, 0xap+0 + +0 i)
> > | Result:
> > |  is:          1.0239999999999989e+03   0x1.ffffffffffff7p+9
> > |  should be:   1.0240000000000000e+03   0x1.0000000000000p+10
> > |  difference:  1.0231815394945442e-12   0x1.2000000000000p-40
> > |  ulp       :  4.5000
> > |  max.ulp   :  2.0000
> > | Maximal error of real part of: cpow_downward
> > |  is      : 5 ulp
> > |  accepted: 2 ulp
> > | Maximal error of imaginary part of: cpow_downward
> > |  is      : 1 ulp
> > |  accepted: 1 ulp
> > | Failure: Test: Real part of: cpow_towardzero (0x2p+0 + +0 i, 0xap+0 + +0 i)
> > | Result:
> > |  is:          1.0239999999999989e+03   0x1.ffffffffffff7p+9
> > |  should be:   1.0240000000000000e+03   0x1.0000000000000p+10
> > |  difference:  1.0231815394945442e-12   0x1.2000000000000p-40
> > |  ulp       :  4.5000
> > |  max.ulp   :  2.0000
> > | Maximal error of real part of: cpow_towardzero
> > |  is      : 5 ulp
> > |  accepted: 2 ulp
> > | Maximal error of imaginary part of: cpow_towardzero
> > |  is      : 1 ulp
> > |  accepted: 1 ulp
> > | 
> > | Test suite completed:
> > |   50 test cases plus 46 tests for exception flags and
> > |     46 tests for errno executed.
> > |   4 errors occurred.
> 
> These failures look pretty much like what we accept on other targets.

It goes up to 8 ULPs for float. I had the impression it is too much.

> You should simply regenerate the ulps file, see “make reben-ulps” in
> math/README.libm-test.  Post the patch before committing it if you still
> feel unsure about this.

I have just done that.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net