commit 659c0411880328ed341ca26b43d069ec5269a8b5

Author: H.J. Lu <hjl.tools@gmail.com>

Date:   Thu Jun 11 09:03:56 2020 -0700

    strcmp: Add a testcase for page boundary

    Add a strcmp testcase to cover cases where both strings end on the page

    boundary.

diff --git a/string/test-strcmp.c b/string/test-strcmp.c

index 8d4784de80..6a840fc04b 100644

--- a/string/test-strcmp.c

+++ b/string/test-strcmp.c

@@ -359,6 +359,38 @@ check (void)

     }

 }

+static void

+check2 (void)

+{

+  /* To trigger bug 25933, we need a size that is equal to the vector

+     length times 4. In the case of AVX2 for Intel, we need 32 * 4.  We

+     make this test generic and run it for all architectures as additional

+     boundary testing for such related algorithms.  */

+  size_t size = 32 * 4;

+  CHAR *s1 = (CHAR *) (buf1 + (BUF1PAGES - 1) * page_size);

+  CHAR *s2 = (CHAR *) (buf2 + (BUF1PAGES - 1) * page_size);

+  int exp_result;

+

+  memset (s1, 'a', page_size);

+  memset (s2, 'a', page_size);

+  s1[(page_size / CHARBYTES) - 1] = (CHAR) 0;

+  s2[(page_size / CHARBYTES) - 1] = (CHAR) 0;

+

+  /* Iterate over a size that is just below where we expect the bug to

+     trigger up to the size we expect will trigger the bug e.g. [99-128].

+     Likewise iterate the start of two strings between 30 and 31 bytes

+     away from the boundary to simulate alignment changes.  */

+  for (size_t s = 99; s <= size; s++)

+    for (size_t s1a = 30; s1a < 32; s1a++)

+      for (size_t s2a = 30; s2a < 32; s2a++)

+	{

+	  CHAR *s1p = s1 + (page_size / CHARBYTES - s) - s1a;

+	  CHAR *s2p = s2 + (page_size / CHARBYTES - s) - s2a;

+	  exp_result = SIMPLE_STRCMP (s1p, s2p);

+	  FOR_EACH_IMPL (impl, 0)

+	    check_result (impl, s1p, s2p, exp_result);

+	}

+}

 int

 test_main (void)

@@ -367,6 +399,7 @@ test_main (void)

   test_init ();

   check();

+  check2 ();

   printf ("%23s", "");

   FOR_EACH_IMPL (impl, 0)