stdlib: Add testcases for llabs(). (BZ #30263)

Test minimum and maximum long long values, zero, 32bit crossover points, and
part of the range of long long values.  Use '-fno-builtin' to ensure we are
testing the implementation.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/stdlib/tst-llabs.c b/stdlib/tst-llabs.c
new file mode 100644
index 0000000000..be3cd78ceb
--- /dev/null
+++ b/stdlib/tst-llabs.c
@@ -0,0 +1,55 @@
+/* Basic tests for llabs.
+   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>
+
+#define LARGE_PRIME 49999
+
+static int do_test (void)
+{
+  long i;
+
+  TEST_COMPARE(llabs(LLONG_MAX), LLONG_MAX);
+  TEST_COMPARE(llabs(LLONG_MIN + 1), LLONG_MAX);
+  TEST_COMPARE(llabs(0x00000000ffffffffL), 0x00000000ffffffffL);
+  TEST_COMPARE(llabs(0x0000000100000000L), 0x0000000100000000L);
+  TEST_COMPARE(llabs(0x80000000ffffffffL), 0x7fffffff00000001L);
+  TEST_COMPARE(llabs(0x8000000100000000L), 0x7fffffff00000000L);
+  TEST_COMPARE(llabs(-1), 1);
+  TEST_COMPARE(llabs(0), 0);
+  TEST_COMPARE(llabs(1), 1);
+
+  for (i = LLONG_MIN + 1; i < LLONG_MIN + INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE(llabs(i), -i);
+
+  for (i = LLONG_MAX - INT_MAX; i < LLONG_MAX - LARGE_PRIME; i += LARGE_PRIME)
+    TEST_COMPARE(llabs(i), i);
+
+  for (i = INT_MIN + 1; i < 0; i += LARGE_PRIME)
+    TEST_COMPARE(llabs(i), -i);
+
+  for (i = 0; i < INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE(llabs(i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>