The wiki "Regeneration" page has this to say about update ULPs.
"The libm-test-ulps files are semiautomatically updated. To
update an ulps baseline, run each of the failing tests (test-float,
test-double, etc.) with -u; this will generate a file called ULPs;
concatenate each of those files with the existing libm-test-ulps
file, after removing any entries for particularly huge numbers of
ulps that you do not want to mark as expected. Then run
gen-libm-test.pl -n -u FILE where FILE is the concatenated file
produced in the previous step. This generates a file called
NewUlps which is the new sorted version of libm-test-ulps."
The same information is listed in math/README.libm-test, and is a
lot of manual work that you often want to run over-and-over again
while working on a particular test.
The `regen-ulps' convenience target does this automatically for
developers.
We strictly assume the source tree is readonly and add a
new --output-dir option to libm-test.inc to allow for writing
out ULPs to $(objpfx).
When run the new target does the following:
* Starts with the baseline ULPs file.
* Runs each of the libm math tests with -u.
* Adds new changes seen with -u to the baseline.
* Sorts and prepares the test output with gen-libm-test.pl.
* Leaves math/NewUlps in your build tree to copy to your source
tree, cleanup, and checkin.
The math test documentation in math/README.libm-test is updated
document the new Makefile target.
---
2013-04-06 Carlos O'Donell <carlos@redhat.com>
* Makefile.in (regen-ulps): New target.
* math/Makefile [ifneq (no,$(PERL)]: Declare regen-ulps with .PHONY.
[ifneq (no,$(PERL)] (run-regen-ulps): New variable.
[ifneq (no,$(PERL)] (regen-ulps): New target.
[ifeq (no,$(PERL)] (regen-ulps): New target.
* math/libm-test.inc (ulps_file_name): Define.
(output_dir): New variable.
(options): Add "output-dir" option.
(parse_opt): Handle 'o' case.
(main): If output_dir is non-NULL use it as a prefix
otherwise use "".
* math/README.libm-test: Update `How can I generate "libm-test-ulps"?'
The patch increase the high value to check if expl overflows. Current
high mark value is not really correct, the algorithm accepts high values.
It also adds a correct wrapper function to check for overflow and underflow.
* math/Makefile: Recognize gmp-sysdep_routines.
* sysdeps/sparc/sparc64/multiarch/Makefile: Add VIS3 optimized GMP routines
to sysdeps.
* sysdeps/sparc/sparc64/multiarch/add_n-vis3.S: New file.
* sysdeps/sparc/sparc64/multiarch/add_n.S: New file.
* sysdeps/sparc/sparc64/multiarch/addmul_1-vis3.S: New file.
* sysdeps/sparc/sparc64/multiarch/addmul_1.S: New file.
* sysdeps/sparc/sparc64/multiarch/mul_1-vis3.S: New file.
* sysdeps/sparc/sparc64/multiarch/mul_1.S: New file.
* sysdeps/sparc/sparc64/multiarch/sub_n-vis3.S: New file.
* sysdeps/sparc/sparc64/multiarch/sub_n.S: New file.
* sysdeps/sparc/sparc64/multiarch/submul_1-vis3.S: New file.
* sysdeps/sparc/sparc64/multiarch/submul_1.S: New file.
With help from Joseph Myers.
* sysdeps/ieee754/ldbl-128/s_atanl.c (__atanl): Handle tiny and
very large arguments properly.
* math/libm-test.inc (atan_test): New tests.
(atan2_test): New tests.
* sysdeps/sparc/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
With help from Joseph Myers.
* sysdeps/ieee754/flt-32/e_j0f.c (__ieee754_y0f): Adjust tinyness
cutoff to 2**-13.
* sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_y1f): Adjust tinyness
cutoff to 2**-25.
* sysdeps/ieee754/ldbl-128/e_j0l.c (U0): New constant.
( __ieee754_y0l): Avoid arithmetic underflow when 'x' is very
small.
* sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_y1l): Likewise.
* math/libm-test.inc (y0_test): New tests.
(y1_test): New tests.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
* sysdeps/sparc/fpu/libm-test-ulps: Update.
* sysdeps/i386/i686/fpu/multiarch/Makefile (sysdep_routines):
Add s_sinf-sse2, s_conf-sse2.
* sysdeps/i386/i686/fpu/multiarch/s_sinf-sse2.S: New file.
* sysdeps/i386/i686/fpu/multiarch/s_cosf-sse2.S: New file.
* sysdeps/i386/i686/fpu/multiarch/s_sinf.c: New file.
* sysdeps/i386/i686/fpu/multiarch/s_cosf.c: New file.
* sysdeps/ieee754/flt-32/s_sinf.c (SINF, SINF_FUNC): Add macros
for using routine as __sinf_ia32.
Use macro for function declaration and weak_alias.
* sysdeps/ieee754/flt-32/s_cosf.c (COSF, COSF_FUNC): Add macros
for using routine as __cosf_ia32.
Use macro for function declaration and weak_alias.
* sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S: Fix Copyright.
* sysdeps/i386/i686/fpu/multiarch/e_expf.c: Fix Copyright.
* sysdeps/x86_64/fpu/s_sinf.S: New file.
* sysdeps/x86_64/fpu/s_cosf.S: New file.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
* math/libm-test.inc (cos_test): Add more test cases.
(sin_test): Likewise.
(sincos_test): Likewise.
For some tests, just claim that fetestexcept() always returns true,
so the rest of the test can be compiled.
For libm-test, provide known bogus values for unsupported rounding
modes, so fesetround() will return failure.
Elsewhere, just add some #ifdefs to avoid code that uses particular
FP exceptions if the exceptions aren't supported.
POSIX 2008 states that if the input for 'logb[f|l]' is a subnormal number
it should be treated as if it were normalized. This means the
implementation should calculate the log2 of the mantissa and add it to the
subnormal exponent (-126 for float and -1022 for double and IBM long
double). This patch takes care of that.
[BZ #6794]
Following Joseph comments about bug 6794, here is a proposed fix. It turned out
to be a large fix mainly because I had to move some file along to follow libm
files/names conventions.
Basically I have added wrappers (w_ilogb.c, w_ilogbf.c, w_ilogbl.c) that now calls
the symbol '__ieee754_ilogb'. The wrappers checks for '__ieee754_ilogb' output and
set the errno and raise exceptions as expected.
The '__ieee754_ilogb' is implemented in sysdeps. I have moved the 's_ilogb[f|l]' files
to e_ilogb[f|l] and renamed the '__ilogb[f|l]' to '__ieee754_ilogb[f|l]'.
I also found out a bug in i386 and x86-64 assembly coded ilogb implementation where
it raises a FE_DIVBYZERO when argument is '0.0'. I corrected this issue as well.
Finally I added the errno and FE_INVALID tests for 0.0, NaN and +-InF argument. Tested
on i386, x86-64, ppc32 and ppc64.