Fix strcpy_chk and stpcpy_chk performance.

Hi, as I wrote in previous patches a performance of checked strcpy and
stpcpy is terrible as these don't use sse2 and are around four times
slower that strcpy and stpcpy now.

As this bug shows that these functions are not performance sensitive I
decided just to improve generic implementation instead for easier
maintainance.

        * debug/strcpy_chk.c: Improve performance.
        * debug/stpcpy_chk.c: Likewise.
        * sysdeps/x86_64/strcpy_chk.S: Remove.
        * sysdeps/x86_64/stpcpy_chk.S: Remove.

2 files changed, 11 insertions, 55 deletions

diff --git a/debug/stpcpy_chk.c b/debug/stpcpy_chk.c
index 91c50316ec..d9e4563cff 100644
--- a/debug/stpcpy_chk.c
+++ b/debug/stpcpy_chk.c
@@ -24,21 +24,11 @@
 
 /* Copy SRC to DEST, returning the address of the terminating '\0' in DEST.  */
 char *
-__stpcpy_chk (dest, src, destlen)
-     char *dest;
-     const char *src;
-     size_t destlen;
+__stpcpy_chk (char *dest, const char *src, size_t destlen)
 {
-  char *d = dest;
-  const char *s = src;
-
-  do
-    {
-      if (__glibc_unlikely (destlen-- == 0))
-	__chk_fail ();
-      *d++ = *s;
-    }
-  while (*s++ != '\0');
-
-  return d - 1;
+  size_t len = strlen (src);
+  if (len >= destlen)
+    __chk_fail ();
+
+  return memcpy (dest, src, len + 1) + len;
 }
diff --git a/debug/strcpy_chk.c b/debug/strcpy_chk.c
index 91bf0dd776..7cacbfe25f 100644
--- a/debug/strcpy_chk.c
+++ b/debug/strcpy_chk.c
@@ -23,45 +23,11 @@
 
 /* Copy SRC to DEST with checking of destination buffer overflow.  */
 char *
-__strcpy_chk (dest, src, destlen)
-     char *dest;
-     const char *src;
-     size_t destlen;
+__strcpy_chk (char *dest, const char *src, size_t destlen)
 {
-  char c;
-  char *s = (char *) src;
-  const ptrdiff_t off = dest - s;
+  size_t len = strlen (src);
+  if (len >= destlen)
+    __chk_fail ();
 
-  while (__builtin_expect (destlen >= 4, 0))
-    {
-      c = s[0];
-      s[off] = c;
-      if (c == '\0')
-        return dest;
-      c = s[1];
-      s[off + 1] = c;
-      if (c == '\0')
-        return dest;
-      c = s[2];
-      s[off + 2] = c;
-      if (c == '\0')
-        return dest;
-      c = s[3];
-      s[off + 3] = c;
-      if (c == '\0')
-        return dest;
-      destlen -= 4;
-      s += 4;
-    }
-
-  do
-    {
-      if (__glibc_unlikely (destlen-- == 0))
-        __chk_fail ();
-      c = *s;
-      *(s++ + off) = c;
-    }
-  while (c != '\0');
-
-  return dest;
+  return memcpy (dest, src, len + 1);
 }