This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] PR string/19907: Incorrect memcpy tests


On Mon, Apr 4, 2016 at 10:02 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> Clear the destination buffer updated by the previous run in bench-memcpy.c
> and test-memcpy.c to catch the error when the following implementations do
> not copy anything.
>
> Tested on x86-64.  OK for master?
>
> H.J.
> ---
>         PR string/19907
>         * enchtests/bench-memcpy.c (do_one_test): Clear the destination
>         buffer updated by the previous run.
>         * string/test-memcpy.c (do_one_test): Likewise.
>         * benchtests/bench-memmove.c (do_one_test): Add a comment.
>         * string/test-memmove.c (do_one_test): Likewise.

I enclosed the patch here again.  Any feedbacks, comments or objections?


-- 
H.J.
From 5a89c0a2d73f7157c358a4d7ec0d6ea92731cb4c Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Mon, 4 Apr 2016 09:38:30 -0700
Subject: [PATCH] Clear destination buffer updated by the previous run

Clear the destination buffer updated by the previous run in bench-memcpy.c
and test-memcpy.c to catch the error when the following implementations do
not copy anything.

	PR string/19907
	* benchtests/bench-memcpy.c (do_one_test): Clear the destination
	buffer updated by the previous run.
	* string/test-memcpy.c (do_one_test): Likewise.
	* benchtests/bench-memmove.c (do_one_test): Add a comment.
	* string/test-memmove.c (do_one_test): Likewise.
---
 benchtests/bench-memcpy.c  | 4 ++++
 benchtests/bench-memmove.c | 1 +
 string/test-memcpy.c       | 6 ++++++
 string/test-memmove.c      | 1 +
 4 files changed, 12 insertions(+)

diff --git a/benchtests/bench-memcpy.c b/benchtests/bench-memcpy.c
index c5a7192..9d9e7b6 100644
--- a/benchtests/bench-memcpy.c
+++ b/benchtests/bench-memcpy.c
@@ -55,6 +55,10 @@ do_one_test (impl_t *impl, char *dst, const char *src,
   size_t i, iters = INNER_LOOP_ITERS;
   timing_t start, stop, cur;
 
+  /* Must clear the destination buffer set by the previous run.  */
+  for (i = 0; i < len; i++)
+    dst[i] = 0;
+
   if (CALL (impl, dst, src, len) != MEMCPY_RESULT (dst, len))
     {
       error (0, 0, "Wrong result in function %s %p %p", impl->name,
diff --git a/benchtests/bench-memmove.c b/benchtests/bench-memmove.c
index c38596b..3858f2a 100644
--- a/benchtests/bench-memmove.c
+++ b/benchtests/bench-memmove.c
@@ -70,6 +70,7 @@ do_one_test (impl_t *impl, char *dst, char *src, const char *orig_src,
   size_t i, iters = INNER_LOOP_ITERS;
   timing_t start, stop, cur;
 
+  /* This also clears the destination buffer set by the previous run.  */
   memcpy (src, orig_src, len);
 #ifdef TEST_BCOPY
   CALL (impl, src, dst, len);
diff --git a/string/test-memcpy.c b/string/test-memcpy.c
index 2a0994c..cb072f8 100644
--- a/string/test-memcpy.c
+++ b/string/test-memcpy.c
@@ -53,6 +53,12 @@ static void
 do_one_test (impl_t *impl, char *dst, const char *src,
 	     size_t len)
 {
+  size_t i;
+
+  /* Must clear the destination buffer set by the previous run.  */
+  for (i = 0; i < len; i++)
+    dst[i] = 0;
+
   if (CALL (impl, dst, src, len) != MEMCPY_RESULT (dst, len))
     {
       error (0, 0, "Wrong result in function %s %p %p", impl->name,
diff --git a/string/test-memmove.c b/string/test-memmove.c
index d2ab3f3..4343329 100644
--- a/string/test-memmove.c
+++ b/string/test-memmove.c
@@ -68,6 +68,7 @@ static void
 do_one_test (impl_t *impl, char *dst, char *src, const char *orig_src,
 	     size_t len)
 {
+  /* This also clears the destination buffer set by the previous run.  */
   memcpy (src, orig_src, len);
 #ifdef TEST_BCOPY
   CALL (impl, src, dst, len);
-- 
2.5.5


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]