x86: Add string/memory function tests in RTM region

At function exit, AVX optimized string/memory functions have VZEROUPPER
which triggers RTM abort.   When such functions are called inside a
transactionally executing RTM region, RTM abort causes severe performance
degradation.  Add tests to verify that string/memory functions won't
cause RTM abort in RTM region.

1 files changed, 54 insertions, 0 deletions

diff --git a/sysdeps/x86/tst-memrchr-rtm.c b/sysdeps/x86/tst-memrchr-rtm.c
new file mode 100644
index 0000000..a57a5a8
--- /dev/null
+++ b/sysdeps/x86/tst-memrchr-rtm.c
@@ -0,0 +1,54 @@
+/* Test case for memrchr inside a transactionally executing RTM region.
+   Copyright (C) 2021 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 <tst-string-rtm.h>
+
+#define LOOP 3000
+#define STRING_SIZE 1024
+char string1[STRING_SIZE];
+
+__attribute__ ((noinline, noclone))
+static int
+prepare (void)
+{
+  memset (string1, 'a', STRING_SIZE);
+  string1[100] = 'c';
+  string1[STRING_SIZE - 100] = 'c';
+  char *p = memrchr (string1, 'c', STRING_SIZE);
+  if (p == &string1[STRING_SIZE - 100])
+    return EXIT_SUCCESS;
+  else
+    return EXIT_FAILURE;
+}
+
+__attribute__ ((noinline, noclone))
+static int
+function (void)
+{
+  char *p = memrchr (string1, 'c', STRING_SIZE);
+  if (p == &string1[STRING_SIZE - 100])
+    return 0;
+  else
+    return 1;
+}
+
+static int
+do_test (void)
+{
+  return do_test_1 ("memrchr", LOOP, prepare, function);
+}