[glibc] stdlib: Add testcases for labs(). (BZ #30263)

[glibc] stdlib: Add testcases for labs(). (BZ #30263)

[Siddhesh Poyarekar]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b11db301e162480d1812937ab0410dc7585f423c

commit b11db301e162480d1812937ab0410dc7585f423c
Author: Joe Simmons-Talbott <josimmon@redhat.com>
Date:   Tue Apr 4 09:57:46 2023 -0400

    stdlib: Add testcases for labs(). (BZ #30263)
    
    Test minimum and maximum long values, zero, and part of the range
    of long values.  Use '-fno-builtin' to ensure we are testing the
    implementation.
    
    Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>

Diff:
---
 stdlib/Makefile   |  2 ++
 stdlib/tst-labs.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/stdlib/Makefile b/stdlib/Makefile
index 2a50822774..0f58a6b62d 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -198,6 +198,7 @@ tests := \
   tst-cxa_atexit \
   tst-environ \
   tst-getrandom \
+  tst-labs \
   tst-limits \
   tst-makecontext \
   tst-makecontext-align \
@@ -289,6 +290,7 @@ LDFLAGS-test-dlclose-exit-race = $(LDFLAGS-rdynamic)
 LDLIBS-test-dlclose-exit-race-helper.so = $(libsupport) $(shared-thread-library)
 
 CFLAGS-tst-abs.c += -fno-builtin
+CFLAGS-tst-labs.c += -fno-builtin
 
 ifeq ($(have-cxx-thread_local),yes)
 CFLAGS-tst-quick_exit.o = -std=c++11
diff --git a/stdlib/tst-labs.c b/stdlib/tst-labs.c
new file mode 100644
index 0000000000..92b456745a
--- /dev/null
+++ b/stdlib/tst-labs.c
@@ -0,0 +1,51 @@
+/* Basic tests for labs.
+   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(labs(LONG_MAX), LONG_MAX);
+  TEST_COMPARE(labs(LONG_MIN + 1), LONG_MAX);
+  TEST_COMPARE(labs(-1), 1);
+  TEST_COMPARE(labs(0), 0);
+  TEST_COMPARE(labs(1), 1);
+
+  for (i = LONG_MIN + 1; i < LONG_MIN + INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE(labs(i), -i);
+
+  for (i = LONG_MAX - INT_MAX; i < LONG_MAX - LARGE_PRIME; i += LARGE_PRIME)
+    TEST_COMPARE(labs(i), i);
+
+  for (i = INT_MIN + 1; i < 0; i += LARGE_PRIME)
+    TEST_COMPARE(labs(i), -i);
+
+  for (i = 0; i < INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE(labs(i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>