This patch adds support in libm-test.inc for automatically running
tests of a function in all rounding modes, in the form of a macro
ALL_RM_TEST to loop over all rounding modes when running tests of a
function, and uses it for functions whose results should always be
independent of the rounding mode.
Conversion of tests of nextafter to ALL_RM_TEST was deferred because
trying that conversion showed up bug 16677. (Finding such a bug of
course illustrates the point of testing more systematically in all
rounding modes rather than only reactively when bugs get reported in a
particular function in a non-default mode.) Conversion of tests where
results can depend on the rounding mode will follow once I add
gen-libm-test.pl support for using different initializers for the
expected results for different rounding modes (again, some conversions
may need deferring until bugs are fixed, depending on how
straightforward they are to XFAIL in a particular context).
Some existing tests get run five times rather than four, with
round-to-nearest tests both run in that as default rounding mode and
also with it explicitly set with fesetround (FE_TONEAREST). This
duplication doesn't seem particularly useful, so ALL_RM_TEST only runs
tests four times.
Tested x86_64 and x86.
* math/libm-test.inc (ALL_RM_TEST): New macro.
(ceil_test): Use ALL_RM_TEST.
(cimag_test): Likewise.
(conj_test): Likewise.
(copysign_test): Likewise.
(cproj_test): Likewise.
(creal_test): Likewise.
(fabs_test): Likewise.
(floor_test): Likewise.
(fmax_test): Likewise.
(fmin_test): Likewise.
(fmod_test): Likewise.
(fpclassify_test): Likewise.
(frexp_test): Likewise.
(ilogb_test): Likewise.
(isfinite_test): Likewise.
(finite_test): Likewise.
(isgreater_test): Likewise.
(isgreaterequal_test): Likewise.
(isinf_test): Likewise.
(isless_test): Likewise.
(islessequal_test): Likewise.
(islessgreater_test): Likewise.
(isnan_test): Likewise.
(isnormal_test): Likewise.
(issignaling_test): Likewise.
(isunordered_test): Likewise.
(logb_test): Likewise.
(logb_downward_test_data): Remove.
(logb_test_downward): Likewise.
(lround_test): Use ALL_RM_TEST.
(llround_test): Likewise.
(modf_test): Likewise.
(nexttoward_test): Likewise.
(remainder_test): Likewise.
(drem_test): Likewise.
(remainder_tonearest_test_data): Likewise.
(remainder_test_tonearest): Likewise.
(drem_test_tonearest): Likewise.
(remainder_towardzero_test_data): Likewise.
(remainder_test_towardzero): Likewise.
(drem_test_towardzero): Likewise.
(remainder_downward_test_data): Likewise.
(remainder_test_downward): Likewise.
(drem_test_downward): Likewise.
(remainder_upward_test_data): Likewise.
(remainder_test_upward): Likewise.
(drem_test_upward): Likewise.
(remquo_test): Use ALL_RM_TEST. Remove comment about x.
(round_test): Use ALL_RM_TEST.
(signbit_test): Likewise.
(trunc_test): Likewise.
(significand_test): Likewise.
(main): Don't call removed functions.
README for libm-test math test suite
====================================
The libm-test math test suite tests a number of function points of
math functions in the GNU C library. The following sections contain a
brief overview. Please note that the test drivers and the Perl script
"gen-libm-test.pl" have some options. A full list of options is
available with --help (for the test drivers) and -h for
"gen-libm-test.pl".
What is tested?
===============
The tests just evaluate the functions at specified points and compare
the results with precomputed values and the requirements of the ISO
C99 standard.
Besides testing the special values mandated by IEEE 754 (infinities,
NaNs and minus zero), some more or less random values are tested.
Files that are part of libm-test
================================
The main file is "libm-test.inc". It is platform and floating point
format independent. The file must be preprocessed by the Perl script
"gen-libm-test.pl". The results are "libm-test.c" and a file
"libm-test-ulps.h" with platform specific deltas.
The test drivers test-double.c, test-float.c, test-ldouble.c test the
normal double, float and long double implementation of libm. The test
drivers with an i in it (test-idouble.c, test-ifloat.c,
test-ildoubl.c) test the corresponding inline functions (where
available - otherwise they also test the real functions in libm).
"gen-libm-test.pl" needs a platform specific files with ULPs (Units of
Last Precision). The file is called "libm-test-ulps" and lives in
platform specific sysdep directory.
How can I generate "libm-test-ulps"?
====================================
To automatically generate a new "libm-test-ulps" run "make regen-ulps".
This generates the file "math/NewUlps" in the build directory. The file
contains the sorted results of all the tests. You can use the "NewUlps"
file as the machine's updated "libm-test-ulps" file. Copy "NewUlps" to
"libm-test-ulps" in the appropriate machine sysdep directory. Verify
the changes, post your patch, and check it in after review.
To manually generate a new "libm-test-ulps" file, first remove "ULPs"
file in the current directory, then you can execute for example:
./testrun.sh math/test-double -u --ignore-max-ulp=yes
This generates a file "ULPs" with all double ULPs in it, ignoring any
previously calculated ULPs, and running with the newly built dynamic
loader and math library (assumes you didn't install your build). Now
generate the ULPs for all other formats, the tests will be appending the
data to the "ULPs" file. As final step run "gen-libm-test.pl" with the
file as input and ask to generate a pretty printed output in the file
"NewUlps":
gen-libm-test.pl -u ULPs -n
Copy "NewUlps" to "libm-test-ulps" in the appropriate machine sysdep
directory.
Note that the test drivers have an option "-u" to output an unsorted
list of all epsilons that the functions have. The output can be read
in directly but it's better to pretty print it first.
"gen-libm-test.pl" has an option to generate a pretty-printed and
sorted new ULPs file from the output of the test drivers.
Contents of libm-test-ulps
==========================
Since libm-test-ulps can be generated automatically, just a few notes.
The file contains lines for maximal errors of single functions, like:
Function "yn":
idouble: 6
The keywords are float, ifloat, double, idouble, ldouble and ildouble
(the prefix i stands for inline).
Adding tests to libm-test.inc
=============================
The tests are evaluated by a set of special test macros. The macros
start with "TEST_" followed by a specification the input values, an
underscore and a specification of the output values. As an example,
the test macro for a function with input of type FLOAT (FLOAT is
either float, double, long double) and output of type FLOAT is
"TEST_f_f". The macro's parameter are the name of the function, the
input parameter, output parameter and optionally one exception
parameter.
The accepted parameter types are:
- "f" for FLOAT
- "b" for boolean - just tests if the output parameter evaluates to 0
or 1 (only for output).
- "c" for complex. This parameter needs two values, first the real,
then the imaginary part.
- "i" for int.
- "l" for long int.
- "L" for long long int.
- "F" for the address of a FLOAT (only as input parameter)
- "I" for the address of an int (only as input parameter)
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