On running tests after from-scratch ulps regeneration, I found that
some libm tests failed with ulps in excess of those recorded in the
from-scratch regeneration, which should never happen unless those ulps
exceed the limit on ulps that can go in libm-test-ulps files.
Failure: Test: atan2_upward (inf, -inf)
Result:
is: 2.35619498e+00 0x1.2d97ccp+1
should be: 2.35619450e+00 0x1.2d97c8p+1
difference: 4.76837159e-07 0x1.000000p-21
ulp : 2.0000
max.ulp : 1.0000
Maximal error of `atan2_upward'
is : 2 ulp
accepted: 1 ulp
Failure: Test: carg_upward (-inf + inf i)
Result:
is: 2.35619498e+00 0x1.2d97ccp+1
should be: 2.35619450e+00 0x1.2d97c8p+1
difference: 4.76837159e-07 0x1.000000p-21
ulp : 2.0000
max.ulp : 1.0000
Maximal error of `carg_upward'
is : 2 ulp
accepted: 1 ulp
The problem comes from the addition of tests for the finite-math-only
versions of libm functions. Those tests share ulps with the default
function variants. make regen-ulps runs the default tests before the
finite-math-only tests, concatenating the resulting ulps before
feeding them to gen-libm-test.pl to generate a new libm-test-ulps
file. But gen-libm-test.pl always takes the last ulps value given for
any (function, type) pair. So, if the largest ulps for a function
come from non-finite inputs, a from-scratch regeneration loses those
ulps.
This patch fixes gen-libm-test.pl, in the case where there are
multiple ulps values for a (function, type) pair - which can only
happen as part of a regeneration - to take the largest ulps value
rather than the last one.
Tested for ARM / MIPS / powerpc-nofpu.
* math/gen-libm-test.pl (parse_ulps): Do not reduce
already-recorded ulps.
* sysdeps/arm/libm-test-ulps: Regenerated.
* sysdeps/mips/mips32/libm-test-ulps: Likewise.
* sysdeps/mips/mips64/libm-test-ulps: Likewise.
* sysdeps/powerpc/nofpu/libm-test-ulps: Likewise.
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