[PATCH 1/3] stdlib: Add testcases for abs(). (BZ #30263)

[Joe Simmons-Talbott <josimmon@redhat.com>]

Test minimum and maximum int values, zero, and a good part of the range
of int values.  Use '-fno-builtin' to ensure we are testing the
implementation.
---
 stdlib/Makefile  |  3 +++
 stdlib/tst-abs.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 stdlib/tst-abs.c

diff --git a/stdlib/Makefile b/stdlib/Makefile
index 5e38f0e6a2..b7e1c028f0 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -184,6 +184,7 @@ tests := \
   testmb2 \
   testrand \
   testsort \
+  tst-abs \
   tst-arc4random-fork \
   tst-arc4random-stats \
   tst-arc4random-thread \
@@ -287,6 +288,8 @@ LDLIBS-test-dlclose-exit-race = $(shared-thread-library)
 LDFLAGS-test-dlclose-exit-race = $(LDFLAGS-rdynamic)
 LDLIBS-test-dlclose-exit-race-helper.so = $(libsupport) $(shared-thread-library)
 
+CFLAGS-tst-abs.c += -fno-builtin
+
 ifeq ($(have-cxx-thread_local),yes)
 CFLAGS-tst-quick_exit.o = -std=c++11
 LDLIBS-tst-quick_exit = -lstdc++
diff --git a/stdlib/tst-abs.c b/stdlib/tst-abs.c
new file mode 100644
index 0000000000..639e29d33f
--- /dev/null
+++ b/stdlib/tst-abs.c
@@ -0,0 +1,43 @@
+/* Basic tests for abs.
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+
+static int do_test (void)
+{
+  int i;
+
+  TEST_COMPARE(abs(INT_MAX), INT_MAX);
+  TEST_COMPARE(abs(INT_MIN + 1), INT_MAX);
+  TEST_COMPARE(abs(-1), 1);
+  TEST_COMPARE(abs(0), 0);
+  TEST_COMPARE(abs(1), 1);
+
+  for (i = INT_MIN + 1; i < 0; i++)
+    TEST_COMPARE(abs(i), -i);
+
+  for (i = 0; i < INT_MAX; i++)
+    TEST_COMPARE(abs(i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
-- 
2.39.2