Replace gen-libm-test.pl with gen-libm-test.py.

Following the recent discussion of using Python instead of Perl and
Awk for glibc build / test, this patch replaces gen-libm-test.pl with
a new gen-libm-test.py script.  This script should work with all
Python versions supported by glibc (tested by hand with Python 2.7,
tested in the build system with Python 3.5; configure prefers Python 3
if available).

This script is designed to give identical output to gen-libm-test.pl
for ease of verification of the change, except for generated comments
referring to .py instead of .pl.  (That is, identical for actual
inputs passed to the script, not necessarily for all possible input;
for example, this version more precisely follows the C standard syntax
for floating-point constants when deciding when to add LIT macro
calls.)  In one place a comment notes that the generation of
NON_FINITE flags is replicating a bug in the Perl script to assist in
such comparisons (with the expectation that this bug can then be
separately fixed in the Python script later).

Tested for x86_64, including comparison of generated files (and hand
testing of the case of generating a sorted libm-test-ulps file, which
isn't covered by normal "make check").

I'd expect to follow this up by extending the new script to produce
the ulps tables for the manual as well (replacing
manual/libm-err-tab.pl, so that then we just have one ulps file
parser) - at which point the manual build would depend on both Perl
and Python (eliminating the Perl dependency would require someone to
rewrite summary.pl in Python, and that would only eliminate the
*direct* Perl dependency; current makeinfo is written in Perl so there
would still be an indirect dependency).

I think install.texi is more or less equally out-of-date regarding
Perl and Python uses before and after this patch, so I don't think
this patch depends on my patch
<https://sourceware.org/ml/libc-alpha/2018-08/msg00133.html> to update
install.texi regarding such uses (pending review).

	* math/gen-libm-test.py: New file.
	* math/gen-libm-test.pl: Remove.
	* math/Makefile [$(PERL) != no]: Change condition to [PYTHON].
	($(objpfx)libm-test-ulps.h): Use gen-libm-test.py instead of
	gen-libm-test.pl.
	($(libm-test-c-noauto-obj)): Likewise.
	($(libm-test-c-auto-obj)): Likewise.
	($(libm-test-c-narrow-obj)): Likewise.
	(regen-ulps): Likewise.
	* math/README.libm-test: Update references to gen-libm-test.pl.
	* math/libm-test-driver.c (struct test_fj_f_data): Update comment
	referencing gen-libm-test.pl.
	* math/libm-test-nexttoward.inc (nexttoward_test_data): Likewise.
	* math/libm-test-support.c: Likewise.
	* math/libm-test-support.h: Likewise.
	* sysdeps/generic/libm-test-ulps: Likewise.

1 files changed, 603 insertions, 0 deletions

diff --git a/math/gen-libm-test.py b/math/gen-libm-test.py
new file mode 100755
index 0000000000..8d156ea8d1
--- /dev/null
+++ b/math/gen-libm-test.py
@@ -0,0 +1,603 @@
+#!/usr/bin/python
+# Generate tests for libm functions.
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import argparse
+from collections import defaultdict
+import re
+
+
+# Sorted list of all float types in ulps files.
+ALL_FLOATS = ('double', 'float', 'float128', 'idouble',
+              'ifloat', 'ifloat128', 'ildouble', 'ldouble')
+
+# Map float types in ulps files to C-like prefix for macros.
+ALL_FLOATS_PFX = {'double': 'DBL',
+                  'ldouble': 'LDBL',
+                  'float': 'FLT',
+                  'float128': 'FLT128'}
+
+# Number of arguments in structure (as opposed to arguments that are
+# pointers to return values) for an argument descriptor.
+DESCR_NUM_ARGS = {'f': 1, 'a': 1, 'j': 1, 'i': 1, 'u': 1, 'l': 1, 'L': 1,
+                  'p': 0, 'F': 0, 'I': 0,
+                  'c': 2}
+
+# Number of results in structure for a result descriptor.
+DESCR_NUM_RES = {'f': 1, 'i': 1, 'l': 1, 'L': 1, 'M': 1, 'U': 1, 'b': 1,
+                 '1': 1,
+                 'c': 2}
+
+# Rounding modes, in the form in which they appear in
+# auto-libm-test-out-* and the order in which expected results appear
+# in structures and TEST_* calls.
+ROUNDING_MODES = ('downward', 'tonearest', 'towardzero', 'upward')
+
+# Map from special text in TEST_* calls for rounding-mode-specific
+# results and flags, to those results for each mode.
+ROUNDING_MAP = {
+    'plus_oflow': ('max_value', 'plus_infty', 'max_value', 'plus_infty'),
+    'minus_oflow': ('minus_infty', 'minus_infty', '-max_value', '-max_value'),
+    'plus_uflow': ('plus_zero', 'plus_zero', 'plus_zero', 'min_subnorm_value'),
+    'minus_uflow': ('-min_subnorm_value', 'minus_zero', 'minus_zero',
+                    'minus_zero'),
+    'ERRNO_PLUS_OFLOW': ('0', 'ERRNO_ERANGE', '0', 'ERRNO_ERANGE'),
+    'ERRNO_MINUS_OFLOW': ('ERRNO_ERANGE', 'ERRNO_ERANGE', '0', '0'),
+    'ERRNO_PLUS_UFLOW': ('ERRNO_ERANGE', 'ERRNO_ERANGE', 'ERRNO_ERANGE', '0'),
+    'ERRNO_MINUS_UFLOW': ('0', 'ERRNO_ERANGE', 'ERRNO_ERANGE', 'ERRNO_ERANGE'),
+    'XFAIL_ROUNDING_IBM128_LIBGCC': ('XFAIL_IBM128_LIBGCC', '0',
+                                     'XFAIL_IBM128_LIBGCC',
+                                     'XFAIL_IBM128_LIBGCC')
+    }
+
+# Map from raw test arguments to a nicer form to use when displaying
+# test results.
+BEAUTIFY_MAP = {'minus_zero': '-0',
+                'plus_zero': '+0',
+                '-0x0p+0f': '-0',
+                '-0x0p+0': '-0',
+                '-0x0p+0L': '-0',
+                '0x0p+0f': '+0',
+                '0x0p+0': '+0',
+                '0x0p+0L': '+0',
+                'minus_infty': '-inf',
+                'plus_infty': 'inf',
+                'qnan_value': 'qNaN',
+                'snan_value': 'sNaN',
+                'snan_value_ld': 'sNaN'}
+
+# Flags in auto-libm-test-out that map directly to C flags.
+FLAGS_SIMPLE = {'ignore-zero-inf-sign': 'IGNORE_ZERO_INF_SIGN',
+                'no-test-inline': 'NO_TEST_INLINE',
+                'xfail': 'XFAIL_TEST'}
+
+# Exceptions in auto-libm-test-out, and their corresponding C flags
+# for being required, OK or required to be absent.
+EXC_EXPECTED = {'divbyzero': 'DIVBYZERO_EXCEPTION',
+                'inexact': 'INEXACT_EXCEPTION',
+                'invalid': 'INVALID_EXCEPTION',
+                'overflow': 'OVERFLOW_EXCEPTION',
+                'underflow': 'UNDERFLOW_EXCEPTION'}
+EXC_OK = {'divbyzero': 'DIVBYZERO_EXCEPTION_OK',
+          'inexact': '0',
+          'invalid': 'INVALID_EXCEPTION_OK',
+          'overflow': 'OVERFLOW_EXCEPTION_OK',
+          'underflow': 'UNDERFLOW_EXCEPTION_OK'}
+EXC_NO = {'divbyzero': '0',
+          'inexact': 'NO_INEXACT_EXCEPTION',
+          'invalid': '0',
+          'overflow': '0',
+          'underflow': '0'}
+
+
+class Ulps(object):
+    """Maximum expected errors of libm functions."""
+
+    def __init__(self):
+        """Initialize an Ulps object."""
+        # normal[function][float_type] is the ulps value, and likewise
+        # for real and imag.
+        self.normal = defaultdict(lambda: defaultdict(lambda: 0))
+        self.real = defaultdict(lambda: defaultdict(lambda: 0))
+        self.imag = defaultdict(lambda: defaultdict(lambda: 0))
+        # List of ulps kinds, in the order in which they appear in
+        # sorted ulps files.
+        self.ulps_kinds = (('Real part of ', self.real),
+                           ('Imaginary part of ', self.imag),
+                           ('', self.normal))
+        self
+
+    def read(self, ulps_file):
+        """Read ulps from a file into an Ulps object."""
+        self.ulps_file = ulps_file
+        with open(ulps_file, 'r') as f:
+            ulps_dict = None
+            ulps_fn = None
+            for line in f:
+                # Ignore comments.
+                if line.startswith('#'):
+                    continue
+                line = line.rstrip()
+                # Ignore empty lines.
+                if line == '':
+                    continue
+                m = re.match(r'([^:]*): (.*)\Z', line)
+                if not m:
+                    raise ValueError('bad ulps line: %s' % line)
+                line_first = m.group(1)
+                line_second = m.group(2)
+                if line_first == 'Function':
+                    fn = None
+                    ulps_dict = None
+                    for k_prefix, k_dict in self.ulps_kinds:
+                        if line_second.startswith(k_prefix):
+                            ulps_dict = k_dict
+                            fn = line_second[len(k_prefix):]
+                            break
+                    if not fn.startswith('"') or not fn.endswith('":'):
+                        raise ValueError('bad ulps line: %s' % line)
+                    ulps_fn = fn[1:-2]
+                else:
+                    if line_first not in ALL_FLOATS:
+                        raise ValueError('bad ulps line: %s' % line)
+                    ulps_val = int(line_second)
+                    if ulps_val > 0:
+                        ulps_dict[ulps_fn][line_first] = max(
+                            ulps_dict[ulps_fn][line_first],
+                            ulps_val)
+
+    def write(self, ulps_file):
+        """Write ulps back out as a sorted ulps file."""
+        # Output is sorted first by function name, then by (real,
+        # imag, normal), then by float type.
+        out_data = {}
+        for order, (prefix, d) in enumerate(self.ulps_kinds):
+            for fn in d.keys():
+                fn_data = ['%s: %d' % (f, d[fn][f])
+                           for f in sorted(d[fn].keys())]
+                fn_text = 'Function: %s"%s":\n%s' % (prefix, fn,
+                                                     '\n'.join(fn_data))
+                out_data[(fn, order)] = fn_text
+        out_list = [out_data[fn_order] for fn_order in sorted(out_data.keys())]
+        out_text = ('# Begin of automatic generation\n\n'
+                    '# Maximal error of functions:\n'
+                    '%s\n\n'
+                    '# end of automatic generation\n'
+                    % '\n\n'.join(out_list))
+        with open(ulps_file, 'w') as f:
+            f.write(out_text)
+
+    @staticmethod
+    def ulps_table(name, ulps_dict):
+        """Return text of a C table of ulps."""
+        ulps_list = []
+        for fn in sorted(ulps_dict.keys()):
+            fn_ulps = [str(ulps_dict[fn][f]) for f in ALL_FLOATS]
+            ulps_list.append('    { "%s", {%s} },' % (fn, ', '.join(fn_ulps)))
+        ulps_text = ('static const struct ulp_data %s[] =\n'
+                     '  {\n'
+                     '%s\n'
+                     '  };'
+                     % (name, '\n'.join(ulps_list)))
+        return ulps_text
+
+    def write_header(self, ulps_header):
+        """Write header file with ulps data."""
+        header_text_1 = ('/* This file is automatically generated\n'
+                         '   from %s with gen-libm-test.py.\n'
+                         '   Don\'t change it - change instead the master '
+                         'files.  */\n\n'
+                         'struct ulp_data\n'
+                         '{\n'
+                         '  const char *name;\n'
+                         '  FLOAT max_ulp[%d];\n'
+                         '};'
+                         % (self.ulps_file, len(ALL_FLOATS)))
+        macro_list = []
+        for i, f in enumerate(ALL_FLOATS):
+            if f.startswith('i'):
+                itxt = 'I_'
+                f = f[1:]
+            else:
+                itxt = ''
+            macro_list.append('#define ULP_%s%s %d'
+                              % (itxt, ALL_FLOATS_PFX[f], i))
+        header_text = ('%s\n\n'
+                       '%s\n\n'
+                       '/* Maximal error of functions.  */\n'
+                       '%s\n'
+                       '%s\n'
+                       '%s\n'
+                       % (header_text_1, '\n'.join(macro_list),
+                          self.ulps_table('func_ulps', self.normal),
+                          self.ulps_table('func_real_ulps', self.real),
+                          self.ulps_table('func_imag_ulps', self.imag)))
+        with open(ulps_header, 'w') as f:
+            f.write(header_text)
+
+
+def read_auto_tests(test_file):
+    """Read tests from auto-libm-test-out-<function> (possibly None)."""
+    auto_tests = defaultdict(lambda: defaultdict(dict))
+    if test_file is None:
+        return auto_tests
+    with open(test_file, 'r') as f:
+        for line in f:
+            if not line.startswith('= '):
+                continue
+            line = line[len('= '):].rstrip()
+            # Function, rounding mode, condition and inputs, outputs
+            # and flags.
+            m = re.match(r'([^ ]+) ([^ ]+) ([^: ][^ ]* [^:]*) : (.*)\Z', line)
+            if not m:
+                raise ValueError('bad automatic test line: %s' % line)
+            auto_tests[m.group(1)][m.group(2)][m.group(3)] = m.group(4)
+    return auto_tests
+
+
+def beautify(arg):
+    """Return a nicer representation of a test argument."""
+    if arg in BEAUTIFY_MAP:
+        return BEAUTIFY_MAP[arg]
+    if arg.startswith('-') and arg[1:] in BEAUTIFY_MAP:
+        return '-' + BEAUTIFY_MAP[arg[1:]]
+    if re.match(r'-?0x[0-9a-f.]*p[-+][0-9]+f\Z', arg):
+        return arg[:-1]
+    if re.search(r'[0-9]L\Z', arg):
+        return arg[:-1]
+    return arg
+
+
+def complex_beautify(arg_real, arg_imag):
+    """Return a nicer representation of a complex test argument."""
+    res_real = beautify(arg_real)
+    res_imag = beautify(arg_imag)
+    if res_imag.startswith('-'):
+        return '%s - %s i' % (res_real, res_imag[1:])
+    else:
+        return '%s + %s i' % (res_real, res_imag)
+
+
+def apply_lit_token(arg, macro):
+    """Apply the LIT or ARG_LIT macro to a single token."""
+    # The macro must only be applied to a floating-point constant, not
+    # to an integer constant or lit_* value.
+    sign_re = r'[+-]?'
+    exp_re = r'([+-])?[0-9]+'
+    suffix_re = r'[lLfF]?'
+    dec_exp_re = r'[eE]' + exp_re
+    hex_exp_re = r'[pP]' + exp_re
+    dec_frac_re = r'(?:[0-9]*\.[0-9]+|[0-9]+\.)'
+    hex_frac_re = r'(?:[0-9a-fA-F]*\.[0-9a-fA-F]+|[0-9a-fA-F]+\.)'
+    dec_int_re = r'[0-9]+'
+    hex_int_re = r'[0-9a-fA-F]+'
+    dec_cst_re = r'(?:%s(?:%s)?|%s%s)' % (dec_frac_re, dec_exp_re,
+                                          dec_int_re, dec_exp_re)
+    hex_cst_re = r'0[xX](?:%s|%s)%s' % (hex_frac_re, hex_int_re, hex_exp_re)
+    fp_cst_re = r'(%s(?:%s|%s))%s\Z' % (sign_re, dec_cst_re, hex_cst_re,
+                                        suffix_re)
+    m = re.match(fp_cst_re, arg)
+    if m:
+        return '%s (%s)' % (macro, m.group(1))
+    else:
+        return arg
+
+
+def apply_lit(arg, macro):
+    """Apply the LIT or ARG_LIT macro to constants within an expression."""
+    # Assume expressions follow the GNU Coding Standards, with tokens
+    # separated by spaces.
+    return ' '.join([apply_lit_token(t, macro) for t in arg.split()])
+
+
+def gen_test_args_res(descr_args, descr_res, args, res_rm):
+    """Generate a test given the arguments and per-rounding-mode results."""
+    # Determine whether any arguments or results, for any rounding
+    # mode, are non-finite.  (For consistency with the old perl
+    # script, this does not handle infinities resulting from
+    # ROUNDING_MAP.)
+    non_finite = False
+    test_snan = False
+    all_args_res = list(args)
+    for r in res_rm:
+        all_args_res.extend(r[:len(r)-1])
+    for a in all_args_res:
+        if 'snan_value' in a:
+            test_snan = True
+            non_finite = True
+        elif 'qnan_value' in a or 'plus_infty' in a or 'minus_infty' in a:
+            non_finite = True
+    # Process the arguments.
+    args_disp = []
+    args_c = []
+    arg_pos = 0
+    for d in descr_args:
+        if DESCR_NUM_ARGS[d] == 0:
+            continue
+        if d == 'c':
+            args_disp.append(complex_beautify(args[arg_pos],
+                                              args[arg_pos + 1]))
+            args_c.append(apply_lit(args[arg_pos], 'LIT'))
+            args_c.append(apply_lit(args[arg_pos + 1], 'LIT'))
+        else:
+            args_disp.append(beautify(args[arg_pos]))
+            if d == 'f':
+                args_c.append(apply_lit(args[arg_pos], 'LIT'))
+            elif d == 'a':
+                args_c.append(apply_lit(args[arg_pos], 'ARG_LIT'))
+            else:
+                args_c.append(args[arg_pos])
+        arg_pos += DESCR_NUM_ARGS[d]
+    args_disp_text = ', '.join(args_disp).replace('"', '\\"')
+    # Process the results.
+    for rm in range(len(ROUNDING_MODES)):
+        res = res_rm[rm]
+        res_pos = 0
+        rm_args = []
+        ignore_result_any = False
+        ignore_result_all = True
+        special = []
+        for d in descr_res:
+            if d == '1':
+                special.append(res[res_pos])
+            elif DESCR_NUM_RES[d] == 1:
+                result = res[res_pos]
+                if result == 'IGNORE':
+                    ignore_result_any = True
+                    result = '0'
+                else:
+                    ignore_result_all = False
+                    if d == 'f':
+                        result = apply_lit(result, 'LIT')
+                rm_args.append(result)
+            else:
+                # Complex result.
+                result1 = res[res_pos]
+                if result1 == 'IGNORE':
+                    ignore_result_any = True
+                    result1 = '0'
+                else:
+                    ignore_result_all = False
+                    result1 = apply_lit(result1, 'LIT')
+                rm_args.append(result1)
+                result2 = res[res_pos + 1]
+                if result2 == 'IGNORE':
+                    ignore_result_any = True
+                    result2 = '0'
+                else:
+                    ignore_result_all = False
+                    result2 = apply_lit(result2, 'LIT')
+                rm_args.append(result2)
+            res_pos += DESCR_NUM_RES[d]
+        if ignore_result_any and not ignore_result_all:
+            raise ValueError('some but not all function results ignored')
+        flags = []
+        if ignore_result_any:
+            flags.append('IGNORE_RESULT')
+        if non_finite:
+            flags.append('NON_FINITE')
+        if test_snan:
+            flags.append('TEST_SNAN')
+        flags.append(res[res_pos])
+        rm_args.append('|'.join(flags))
+        for sp in special:
+            if sp == 'IGNORE':
+                rm_args.extend(['0', '0'])
+            else:
+                rm_args.extend(['1', apply_lit(sp, 'LIT')])
+        for k in sorted(ROUNDING_MAP.keys()):
+            rm_args = [arg.replace(k, ROUNDING_MAP[k][rm]) for arg in rm_args]
+        args_c.append('{ %s }' % ', '.join(rm_args))
+    return '    { "%s", %s },\n' % (args_disp_text, ', '.join(args_c))
+
+
+def convert_condition(cond):
+    """Convert a condition from auto-libm-test-out to C form."""
+    conds = cond.split(':')
+    conds_c = []
+    for c in conds:
+        if not c.startswith('arg_fmt('):
+            c = c.replace('-', '_')
+        conds_c.append('TEST_COND_' + c)
+    return '(%s)' % ' && '.join(conds_c)
+
+
+def cond_value(cond, if_val, else_val):
+    """Return a C conditional expression between two values."""
+    if cond == '1':
+        return if_val
+    elif cond == '0':
+        return else_val
+    else:
+        return '(%s ? %s : %s)' % (cond, if_val, else_val)
+
+
+def gen_auto_tests(auto_tests, descr_args, descr_res, fn):
+    """Generate C code for the auto-libm-test-out-* tests for a function."""
+    for rm_idx, rm_name in enumerate(ROUNDING_MODES):
+        this_tests = sorted(auto_tests[fn][rm_name].keys())
+        if rm_idx == 0:
+            rm_tests = this_tests
+            if not rm_tests:
+                raise ValueError('no automatic tests for %s' % fn)
+        else:
+            if rm_tests != this_tests:
+                raise ValueError('inconsistent lists of tests of %s' % fn)
+    test_list = []
+    for test in rm_tests:
+        fmt_args = test.split()
+        fmt = fmt_args[0]
+        args = fmt_args[1:]
+        test_list.append('#if %s\n' % convert_condition(fmt))
+        res_rm = []
+        for rm in ROUNDING_MODES:
+            test_out = auto_tests[fn][rm][test]
+            out_str, flags_str = test_out.split(':', 1)
+            this_res = out_str.split()
+            flags = flags_str.split()
+            flag_cond = {}
+            for flag in flags:
+                m = re.match(r'([^:]*):(.*)\Z', flag)
+                if m:
+                    f_name = m.group(1)
+                    cond = convert_condition(m.group(2))
+                    if f_name in flag_cond:
+                        if flag_cond[f_name] != '1':
+                            flag_cond[f_name] = ('%s || %s'
+                                                 % (flag_cond[f_name], cond))
+                    else:
+                        flag_cond[f_name] = cond
+                else:
+                    flag_cond[flag] = '1'
+            flags_c = []
+            for flag in sorted(FLAGS_SIMPLE.keys()):
+                if flag in flag_cond:
+                    flags_c.append(cond_value(flag_cond[flag],
+                                              FLAGS_SIMPLE[flag], '0'))
+            for exc in sorted(EXC_EXPECTED.keys()):
+                exc_expected = EXC_EXPECTED[exc]
+                exc_ok = EXC_OK[exc]
+                no_exc = EXC_NO[exc]
+                exc_cond = flag_cond.get(exc, '0')
+                exc_ok_cond = flag_cond.get(exc + '-ok', '0')
+                flags_c.append(cond_value(exc_cond,
+                                          cond_value(exc_ok_cond, exc_ok,
+                                                     exc_expected),
+                                          cond_value(exc_ok_cond, exc_ok,
+                                                     no_exc)))
+            if 'errno-edom' in flag_cond and 'errno-erange' in flag_cond:
+                raise ValueError('multiple errno values expected')
+            if 'errno-edom' in flag_cond:
+                if flag_cond['errno-edom'] != '1':
+                    raise ValueError('unexpected condition for errno-edom')
+                errno_expected = 'ERRNO_EDOM'
+            elif 'errno-erange' in flag_cond:
+                if flag_cond['errno-erange'] != '1':
+                    raise ValueError('unexpected condition for errno-erange')
+                errno_expected = 'ERRNO_ERANGE'
+            else:
+                errno_expected = 'ERRNO_UNCHANGED'
+            if 'errno-edom-ok' in flag_cond:
+                if ('errno-erange-ok' in flag_cond
+                    and (flag_cond['errno-erange-ok']
+                         != flag_cond['errno-edom-ok'])):
+                    errno_unknown_cond = ('%s || %s'
+                                          % (flag_cond['errno-edom-ok'],
+                                             flag_cond['errno-erange-ok']))
+                else:
+                    errno_unknown_cond = flag_cond['errno-edom-ok']
+            else:
+                errno_unknown_cond = flag_cond.get('errno-erange-ok', '0')
+            flags_c.append(cond_value(errno_unknown_cond, '0', errno_expected))
+            flags_c = [flag for flag in flags_c if flag != '0']
+            if not flags_c:
+                flags_c = ['NO_EXCEPTION']
+            this_res.append(' | '.join(flags_c))
+            res_rm.append(this_res)
+        test_list.append(gen_test_args_res(descr_args, descr_res, args,
+                                           res_rm))
+        test_list.append('#endif\n')
+    return ''.join(test_list)
+
+
+def gen_test_line(descr_args, descr_res, args_str):
+    """Generate C code for the tests for a single TEST_* line."""
+    test_args = args_str.split(',')
+    test_args = test_args[1:]
+    test_args = [a.strip() for a in test_args]
+    num_args = sum([DESCR_NUM_ARGS[c] for c in descr_args])
+    num_res = sum([DESCR_NUM_RES[c] for c in descr_res])
+    args = test_args[:num_args]
+    res = test_args[num_args:]
+    if len(res) == num_res:
+        # One set of results for all rounding modes, no flags.
+        res.append('0')
+        res_rm = [res, res, res, res]
+    elif len(res) == num_res + 1:
+        # One set of results for all rounding modes, with flags.
+        if not ('EXCEPTION' in res[-1]
+                or 'ERRNO' in res[-1]
+                or 'IGNORE_ZERO_INF_SIGN' in res[-1]
+                or 'TEST_NAN_SIGN' in res[-1]
+                or 'NO_TEST_INLINE' in res[-1]
+                or 'XFAIL' in res[-1]):
+            raise ValueError('wrong number of arguments: %s' % args_str)
+        res_rm = [res, res, res, res]
+    elif len(res) == (num_res + 1) * 4:
+        # One set of results per rounding mode, with flags.
+        nr_plus = num_res + 1
+        res_rm = [res[:nr_plus], res[nr_plus:2*nr_plus],
+                  res[2*nr_plus:3*nr_plus], res[3*nr_plus:]]
+    return gen_test_args_res(descr_args, descr_res, args, res_rm)
+
+
+def generate_testfile(inc_input, auto_tests, c_output):
+    """Generate test .c file from .inc input."""
+    test_list = []
+    with open(inc_input, 'r') as f:
+        for line in f:
+            line_strip = line.strip()
+            if line_strip.startswith('AUTO_TESTS_'):
+                m = re.match(r'AUTO_TESTS_([^_]*)_([^_ ]*) *\(([^)]*)\),\Z',
+                             line_strip)
+                if not m:
+                    raise ValueError('bad AUTO_TESTS line: %s' % line)
+                test_list.append(gen_auto_tests(auto_tests, m.group(1),
+                                                m.group(2), m.group(3)))
+            elif line_strip.startswith('TEST_'):
+                m = re.match(r'TEST_([^_]*)_([^_ ]*) *\((.*)\),\Z', line_strip)
+                if not m:
+                    raise ValueError('bad TEST line: %s' % line)
+                test_list.append(gen_test_line(m.group(1), m.group(2),
+                                               m.group(3)))
+            else:
+                test_list.append(line)
+    with open(c_output, 'w') as f:
+        f.write(''.join(test_list))
+
+
+def main():
+    """The main entry point."""
+    parser = argparse.ArgumentParser(description='Generate libm tests.')
+    parser.add_argument('-a', dest='auto_input', metavar='FILE',
+                        help='input file with automatically generated tests')
+    parser.add_argument('-c', dest='inc_input', metavar='FILE',
+                        help='input file .inc file with tests')
+    parser.add_argument('-u', dest='ulps_file', metavar='FILE',
+                        help='input file with ulps')
+    parser.add_argument('-n', dest='ulps_output', metavar='FILE',
+                        help='generate sorted ulps file FILE')
+    parser.add_argument('-C', dest='c_output', metavar='FILE',
+                        help='generate output C file FILE from .inc file')
+    parser.add_argument('-H', dest='ulps_header', metavar='FILE',
+                        help='generate output ulps header FILE')
+    args = parser.parse_args()
+    ulps = Ulps()
+    if args.ulps_file is not None:
+        ulps.read(args.ulps_file)
+    auto_tests = read_auto_tests(args.auto_input)
+    if args.ulps_output is not None:
+        ulps.write(args.ulps_output)
+    if args.ulps_header is not None:
+        ulps.write_header(args.ulps_header)
+    if args.c_output is not None:
+        generate_testfile(args.inc_input, auto_tests, args.c_output)
+
+
+if __name__ == '__main__':
+    main()